Do-it-yourself pitched roof - step by step with photos - for a house, barn, garage. Shed roof rafter system: design and installation features Shed rafter pitch

The tempting simplicity of a roof with a single slope inspires thoughts of the opportunity to prove oneself in the field of a successful builder. The construction of a simple structure consists of simply laying rafter legs on the supporting walls. No complex knots, tricky or numerous connections. However, even in the simplest carpentry there are tricks that require thorough study. The future performer needs to know exactly how the stops are attached pitched roof to prevent deformation and damage to the elements of the frame system.

Traditional “wooden” troubles

The design of the rafter frame of a pitched roof is extremely simple. It is a series of parallel laid boards or beams, resting their edges on two walls of different heights. To install and attach the rafter legs to the building structure, a transition element made of wood is used.

Depending on the type of box being installed and the wall material, the function of the transition element is performed by:

Mauerlat. In a shed roof scheme, these are two separately laid wooden beams that complete concrete or brick walls.
The upper frame of the frame structure. A belt made of double stitched boards or timber installed on top of the frame posts.
The upper crown of the foot, made of timber or logs.

The rafter legs and the elements in contact with them are made of wood, which has the property of changing its own dimensions following fluctuations in the background humidity and temperature changes. In spring and autumn, especially during the rainy season, the length of the rafter legs will be slightly longer than in dry summers and frosty winters.

Imagine what will happen if the rafters, rigidly fixed at the top and bottom, increase in size. Gaps will appear in the waterproofing, fasteners will become loose, slate sheets will move, and metal tiles will shift. In addition, deflection and heaving of the roof frame will certainly affect its wear resistance.

However, changes in the linear dimensions of the rafters are not at all the main problem with wooden rafter systems. An unpleasant surprise, if not taken into account, will be the settlement of the newly built box.

It is most pronounced on wooden walls, but it is also very characteristic of structures made of concrete and brick. Let us remember that pitched roofs rest on walls of different heights. Without calculations, you can understand that they will sag by different sizes. Those. there is a threat that, due to the difference in the subsidence of the walls, the new roof will not simply change the angle of the slope. There will be a possibility of disruption of nodes with extremely negative destructive consequences.

Despite the simplicity of pitched roofs and the close-to-horizontal direction of laying the rafters, the listed risks should not be forgotten. The nodes used to fasten the rafter legs of a pitched roof must take into account the “whims” of the wood.

The work of the developer of his own pitched roof project is to find the right solution to three important problems, according to which:

It must be possible to move the wooden parts relative to each other.
All possible causes of connection failure should be excluded.
It is necessary to provide the rafters with the opportunity to adapt to the consequences of wall subsidence so that they can take a stable position.

The rafter legs of shed roofs erected over walls of equal height are classified as layered. Hanging type is used if the box being equipped has walls of equal height, and the slope is formed by rafter triangles.

Everything is clear about fastening the triangles: with the horizontal side they are installed on the harness or Mauerlat, they have a maximum joining area with the supporting elements, and are fixed in the usual way.

With layered rafter legs, everything is much more complicated. They are installed at an angle to the supporting elements. Without processing and preparation for installation, the rafters have only two unreliable points of contact with the strapping or Mauerlat.

No matter how powerful the fastener is, two points are not enough to firmly seat the part. Even with a slight impact, such a slope will simply slide down along with the continuous sheathing and multi-layer roofing cake. However, there are methods invented by ancient builders to avoid such troubles.

In order to prevent unwanted movements, the contact area between the rafters and the supporting element is increased, for this purpose the following is done:

Selection of cuts. These are cuts in the shape of a triangle or a triangle with a tooth. They are cut exclusively on the rafters, so as not to weaken the supporting mauerlat.
The top or bottom edge of the rafter leg is filed down, thereby creating a support platform that increases stability. Performed strictly vertically or horizontally.

Depending on the type and location of sawing or trimming, notches and cuts may or may not limit movement wooden part. The restrictions are considered relative, because there are no absolutely rigid fastenings in the construction of pitched roofs. Experts classify the units used by degrees of freedom: from one to four.

In the construction of roofs with one slope, the following most often appear:

Fastening nodes with one degree of freedom are practically stationary connections that allow the rafter to rotate slightly around the fastening point.
Fastening units with two degrees of freedom are connections that provide the ability to rotate around the fastener and cause slight horizontal displacement.
Fastening units with three degrees of freedom are connections that allow rotation and displacement horizontally and vertically.

The presence of degrees of freedom does not mean that the rafter will be able to rotate and move freely in the area of the node. They are fastened quite rigidly, because they have to hold the lathing, corrugated sheets or other type of covering, or snow cover.

The connection will only show its capabilities if the load is exceeded. Then the rafter legs will just move and take a new position, and the system will remain without damage.

Any diagram of a pitched roof clearly shows us the presence of at least two connecting nodes. Let's divide them conditionally into upper and lower. In construction rafter roofs The rule applies: if one of the nodes is rigidly fixed, then the second should have more opportunities for movement.

Projecting and simplifying the technological principle, we can say: if the fastenings in the upper nodes of a pitched roof are made rigidly, then the lower connections must be freer to ensure the possibility of displacement when the pressure is exceeded. And vice versa: if the lower mount is practically motionless, then the rafter at the top needs to be provided with some reserve for movement and rotation.

Details about the components of a pitched roof

After getting acquainted with the theoretical side of the issue of fastening the rafters of a pitched roof, you can begin practical research on the popular nodal schemes. Note that most projects of systems with a single slope are designed for the installation of rafters that form overhangs due to their own length. However, when covering large spans, it happens that the standard dimensions of lumber are not enough. In these cases, fillets are sewn to the rafters, creating an overhang. They are installed on the side of the installed leg and do not affect the principle of knot formation at all.

The second reason for using fillies in the formation of overhangs is that the rafters are too heavy, which is very difficult to lift and install. The third prerequisite lies in the features of the nodal fastenings: if the lower heel is installed on a slider with a trimmed edge.

No. 1: Support at the top and articulated bottom

A scheme with a rigidly fixed top and a relatively movable bottom is used in the construction of roofs over extensions, in the construction of objects with a steep roof and a significant difference between the heights of the supporting walls.

Simply put, where the top edge of the rafter rests on wooden beam, the purlin or wall of the main building and there is no space left for her to move. The lower node in such situations is calculated on a slider, allowing it to move slightly.

Algorithm for the classic version with the top resting on the purlin:

We install the supports of the purlin frame. On the framing of the frame building on opposite sides we install supports sewn from three pieces of 25×100 boards. The middle segment should be 75mm shorter than the outer ones in order to form a kind of recess.
We build a purlin frame. We place a 25×150 board of the required length into the recess.
We apply a 25×100 board of arbitrary length to the end of the future roof, but approximately 30 cm longer than the diagonal drawn from the top of the purlin to the frame. We mark the vertical line of the upper cut, outlining the adjacent edge of the purlin. We mark the line of the bottom cut and the vertical for trimming the edge of the rafter.
We cut out the rafter according to the marks, try it on after the fact, and, if necessary, adjust the cuts.
According to the template we made, we cut out and install the rafter legs.

We select the type of fastener based on the expected load. It is more convenient to fix the top with corners, the bottom with corners, screwing no more than three screws into them, or with sliding supports. If necessary, the lower knot can be stabilized by sewing a support block to the rafter leg from below.

The connection point with the purlin can be designed slightly differently: the rafter is laid on the beam using a notch. Here the groove is selected strictly according to the size of the material. But if it is necessary to increase the degree of freedom, the horizontal wall of the notch is beveled at a slight angle, and the lower unit is equipped with a sewing strip.

No. 2: Top and bottom are articulated and fixed

The scheme is applicable when arranging boxes whose walls have already undergone intensive shrinkage. Suitable for isolated objects. The upper knot is made in the form of a triangular notch, the lower one is in the form of a cut with a tooth resting on the Mauerlat.

The process of constructing a lean-to rafter system:

We install the blank board edgewise on the mauerlat bars anywhere on the roof.
We lay a well-trimmed piece of board flat on the lower Mauerlat. We place it so that the outer edge coincides with the inner edge of the Mauerlat. Having outlined the scrap, we get an outline of the lower attachment point.
We transfer the trim to the area of the upper notch and outline it, because the lower heel of the rafter will decrease exactly by this amount.
The blank with the nodes drawn and then sawn will serve as a template. Using it, we produce the number of legs specified by the project.
We install the rafters. We fix them at the bottom with staples or pins, and at the top with corners.

If you need to increase the degree of freedom, by analogy with the previous method, the vertical edge of the upper notch will need to be slightly beveled. The cutting angle will then be not 90º, but 95 - 97º. Experienced carpenters make simple cuts directly on site, turning the workpiece upside down. Beginning performers should not imitate in the first stages.

The rafter template is used in roof construction only when there is no doubt about the geometric characteristics of the frame. In opposite situations, the rafters are tried on and made individually. First, the outermost elements of the system are installed, then the row legs along the cord stretched between them.

One of the variations on the theme of two hinged-fixed units involves the installation of a vertical cut at the top and a notch with a tooth at the bottom. Work on their installation is carried out as follows:

We install the blank board on the mauerlat so that its lower corner is directly above the outer edge of the beam.
At the top, using a piece of board, mark a vertical line (x) and measure its length.
We transfer the length of the upper cut to the area of the lower node. We set aside the length of the cut (x) vertically from the inner upper edge of the mauerlat.
From the resulting point we draw a horizontal line. The result is a notch with a tooth.
We cut out the nodes according to the marks, install them in place, fasten them with corners, duplicate the lower nodes with staples.

As the size (x) increases, the roof slope will increase, and as it decreases, it will decrease.

No. 3: Free top and hinged-fixed bottom

An ideal scheme for constructing a pitched roof with rafters, the edges of which extend beyond the walls. After some adjustments it can be used in the arrangement of extensions.

We install the workpiece edgewise on the upper and lower mauerlat beams with the edges moving beyond the walls. Here you need an assistant to hold the board up.
We apply a template - a trimmed piece of board sequentially to the lower and upper mauerlat so that the outer edge of the template coincides with the outer edge of the beams. We mark the lines of the upcoming cuts.
We select cuts according to the outlined lines. We slightly bevel the vertical wall of the upper notch.
We install the rafter, fix it at the top with nails or corners, and at the bottom with staples.
We manufacture and install the remaining rafters in the same way.

It is clear that mobility and its antagonist are relative concepts. However, one cannot treat them with lukewarmness. It is necessary to take into account the degree of freedom of the node both during the design period and when choosing fasteners. Lack of structural mobility will lead to deformation, excess will contribute to instability.

No. 4: Mobility of both attachment points

A scheme with two moving units can be used if both fastening connections have no more than two degrees of freedom. Those. horizontal mixing is prevented by restrictive devices installed at the top and bottom.

Let's consider an example in which the rafters of the extension are laid at the top into niches cut out in the wall. This means that horizontal displacement is excluded, rotation and some vertical movement are possible. The bottom is planted using notches, but is limited in the horizontal direction by metal corners.

Step-by-step actions of the builder of a single-slope building:

We are preparing the object for work. On the brick wall of the extension we place a mauerlat made of 100×150 timber. We lay it on the wide side closer to the inner edge of the wall. We fasten with anchors every 80cm. In the main wall of the building at the designed height, we cut out grooves for the upper heels of the rafters. The depth of the cuts is 12 cm, the step between them is 70 cm. If you don't want to bother with gouging, you can use metal brackets screwed to the wall.
Making a template for the rafter leg. Place the blank board with its upper edge in the groove and the lower edge on the mauerlat. Having retreated 10 cm from the lower corners of the workpiece in the horizontal direction, we draw two triangular notches.
According to the indications of the template, we make rafters. We install them, fixing the position with metal corners.

The device method is valid when covering spans up to 4.5 m. If you need to cover a larger span, the rafters will need a support group consisting of struts.

No. 5: Rigid attachment to an inclined harness

The method is used in frame construction, because the supporting element can only be laid at an angle on racks sawn at an angle. Either the racks of the frame itself or the cantilever-girder structure installed on the box are sawed down at an angle. In principle, the latter option is quite suitable for constructing a pitched roof over concrete and brick walls.

Stages of installing a pitched roof using an inclined frame:

We assemble a structure that creates a roof slope. On the gable side of the frame building we install short posts with the top edge sawn at an angle.
We lay the boards on the sloping top of the posts in one row for small outbuildings, in two for more serious houses.
We equip the end sides of the roof with frames in the shape of a right triangle, the hypotenuse of which should follow the line of the slope.
We apply the rafter to the end of the roof to mark the line of the bottom gash.
Using the template, we make the required number of rafter legs. We install them on the harness, fixing the position of the elements with metal corners.

Without a shadow of a doubt, we classify the last method as the simplest category. Of all the methods of attaching rafters to the frame and beams of the Mauerlat of a pitched roof, this is the most conducive to attempts at independent implementation.

Final fastening work

After installing the entire row of rafter legs, we check the design position of the elements and the distances between them. We apply an arbitrary board flat to the frame of the ramp, identify shortcomings and correct the flaws. Then we fasten the rafters with staples or ties to the walls one at a time in regions with medium and low wind activity. We fix each leg in areas with high wind load.

The fillies, if they are planned for installation, are made of material with dimensions half smaller than the dimensions of the rafter legs. Sew them to the side of the rafter. The length of the sewn area is on average 60-80cm.

Video to visually study the process

The presented methods and schemes for fastening the rafters of a pitched roof have been tested in practice. They are most often used in their “pure form”. However, some adjustments according to specific technical conditions are not excluded.

The key to the longevity of a residential house or any other purpose will be a safe and durable roof. The quality of installation is based on the correct selection of materials, fasteners and technology for connecting structural components.

Whatever the roof, it requires the presence of several basic elements, among them a rafter frame, sheathing and roofing package. As for the rafter system, it represents the main supporting element of the roof, which is also sometimes called the skeleton. The sheathing is the ribs on which the covering material is installed. The varieties of rafter systems can be reduced to two main classes, among them hanging rafters and those called layered.

Hanging rafters

If you need to attach the rafters to the mauerlat, then it is important to know that the first of them can be hanging. They are formed by a triangular rigid coupling of the structure, which has the form of trusses. They include timber and rafter boards. In this case, the puffs are removed onto the Mauerlat. The latter is a thick support beam that is securely fastened to the top of the wall. Its task is to create the basis for the profile frame.

Layered rafters

If it is necessary to attach the rafters to the mauerlat, then you need to remember that the first of them can be layered. In this case, the rafter beams, which are located at an angle, have two points of support at the ends, namely the Mauerlat and the ridge beam. The latter rests through intermediate posts on the wall of the building located inside. A massive longitudinal beam can also act as a support.

Options for attaching rafters to the Mauerlat

A feature of a building inclined frame is that its components can have a movable and a fixed connection with each other. If we are talking about a wooden building, then the last crown of a log house or timber, which belongs to top harness walls If there is a need to attach the rafters to the mauerlat, then the connection of the upper ends with the ridge is made articulated and movable. This also applies to the pairing of the lower part. This requirement is due to a reduction in the resulting internal stresses that are characteristic of the rafter frame. The causes of such stress are temperature fluctuations, deformation of wooden buildings, shrinkage of the house, as well as uneven loads from snow and wind. If manipulations under the ridge are carried out at a considerable height, which is not very convenient, then it is preferable to choose a rigid connection of the rafter boards. This leaves freedom of movement for the lower ends.

Fixing the rafter leg

When there is a need to fasten the rafters to the Mauerlat, the lower unit is usually fixed in one of the following ways. The technology can be spacer; it involves the arrangement of a fixed connection unit, in this case the rafters rest rigidly against the base of the beam. The connection can be sliding. In this case, the rafter will slide along the surface of the beam, being held on it solely with the help of fasteners. Both of these methods are quite widespread and have their own characteristics.

Types of fixation without gash and with its presence

Fastening the rafters to the mauerlat without cutting is applicable exclusively for sliding mating. In this case, the rafter leg will rest freely with its edge on the surface of the Mauerlat. In this case, corners are used as fasteners. This fastening option is not considered completely reliable under heavy roof loads. For this reason, it is used to cover spans with small dimensions. In order to ensure a more reliable pairing of the components of the lower assembly, the blocking tooth-cut is cut out. It can be done using a certain technology. Instead of a groove in the rafters, a persistent block is often used, which is pierced for strength. If it was decided to fasten the rafters to the mauerlat with staples, then the cut should be made in the rafter leg, and not in the mauerlat. This will prevent deformation and weakening.

Types of fasteners

Fastening the rafters to the mauerlat, a photo of which is presented in the article, can be done using nails and staples, as the most simple option a wire rod protrudes, which is folded in several rows. On the market today building materials you can find fasteners various types. Nails used in connections prevent loosening of fasteners. However, for this you should use a notched fastener or a so-called twisted nail. If you decide to use bolts and screws, it is important to place washers or plates made of steel under them. This will prevent the fasteners from sinking.

Rules for carrying out work on fastening rafters

If the rafters are attached to the mauerlat of a pitched roof, then the workpiece is laid on the ridge beam with its upper edge, while the lower corner should be connected to the inner edge of the mauerlat. Using a piece of board that acts as a template, it is necessary to draw a line on the surface of the rafters that is parallel to the upper border of the Mauerlat. If you are going to make a gash, you need to mark the stubborn teeth on the inside or outside. Next, cutting is done along the lines. When making cuts, the corners must be marked to ensure a tight fit of all elements of the wooden structure. When the rafters are fastened to the mauerlat with nails, next stage you need to install the element in its place. Now you can commit. If nails are used, they must be installed at an angle through the rafter board into the beam, two on each side. If it was decided to use staples, then they are installed from the inside of the beam approximately in the central part. Its other end turns at a right angle towards the rafters, and then hammers into them.

Alternative uses of fasteners

If the rafters are attached to the mauerlat of a gable roof using rolled wire, then it must be folded in four rows, forming a clamp. With the help of it, the rafter is screwed to the Mauerlat from the outside. Most often, mating with staples or wires is combined with other types of connections, and you get a backup fastening. Instead of wire, you can use perforated mounting tape. Corners are used quite often. They are screwed with screws to the upper edge of the mauerlat on both sides of the rafters; you need to strengthen the corners to it. In order to ensure more impressive reliability, corners should be used with two rows of holes, as well as a stiffening rib. Instead of corners, you can use special plates that have the ends turned at a right angle.

If the rafters are attached to the mauerlat with corners, then the so-called slides can be used. They have a sliding plate. With their help, you can provide a reliable connection that compensates for deformations. After the installation of the lower unit is completed, you can begin connecting to the ridge beam. Building a roof takes half the time it takes to build a house. The material costs for it are approximately the same. It is important to prevent even the smallest errors, which can become a source of very significant problems when using the system.

Rules for fastening

If rafters are attached to the mauerlat in a wooden house, then only high-quality elements should be used. Savings in this case are unacceptable, since low-quality hardware will not guarantee the creation of a durable and stable roof. Cuts, if any, on the rafters must be done very carefully, this will avoid the need to install additional gaskets or liners. Such parts will help ensure a good connection, but it is best to do without them. This is due to the fact that over time they can become deformed and fall out altogether. This will cause the entire structure to weaken. It is recommended to install rafters on steel plates and corners. It is best to purchase them before starting work on the roof. Otherwise, you will have to stop the installation for a while, which will extend the period of manipulation. However, you can use other types of fastenings, which were described above. But this will only be a temporary measure. To install timber, the most optimal option is nails and screws. To create a durable structure, bolted connections of the stud type must be used. When installing a roof, experts recommend using sliding fasteners. This technology is good for pairing rafters with the Mauerlat. Mobility of the structure is a prerequisite. Before fixing the rafters, it is necessary to prepare special recesses. They are able to provide a tight, hermetically sealed fit of the elements. To ensure that the notches are the same, templates should be used. If the roof slopes are made at different angles, in this case the templates must be made separately. If there are cuts in the structure, then their depth should be equal to 1/4 of the width of the rafter leg. To comply with this parameter, additional accurate measurements must be taken.

Conclusion

When the rafters are attached to the mauerlat without cutting, it is important to ensure the strength and stability of the roof when exposed to strong winds. It is also important to take care of the problem of bursting force, which has a significant impact. The roofing system must be assembled initially on the ground. This preparation is considered necessary. All measurements can be taken, as well as insertions into the Mauerlat. Ultimately, you need to fit and install the elements in place. The finished parts must be installed on the structure one by one. When purchasing hardware, you should remember that their poor quality can cause not only distortions, but also the collapse of the entire structure. It is for this same reason that it is not recommended to use lining material, making the connection as strong as possible, since it will not become loose over time and will not require repairs.

December 27, 2016

It is planned to build a roof, it is necessary simple design With good characteristics strength and reliability? In this case, a pitched roof would be an excellent option. It will make your house, garage, extension or other structure original in its own way. In addition, the rafter system of a pitched roof is easy to install. You can do it without having construction experience.

Why single-pitched

The roof structure of 1 slope has the following advantages:

When building on a pitched roof, you can use any type of roofing material. Because the angle of inclination can be very small, you can build an almost flat roof.
The windage of this design is much less than that of a gable one. This option can be used in areas with strong winds.
Ease of installation and operation. You can build it yourself.
Light weight compared to other types of roofing.
For a pitched roof, you can build slopes of several floors. This solution will add design to your home.
Construction of a pitched roof is the most economical and does not require much time.
In this design, water rolls off only on one side.
The roof is suitable for any type of construction.

Like any other structure, a pitched roof has several disadvantages:

At a small angle of inclination the area attic space minimal.
Has a less attractive appearance. What can be corrected with the imagination of a designer.

Design calculation

The rafter system of a pitched roof essentially consists of layered rafter legs. The rafters must be fastened parallel to each other. The rafters, in turn, are supported by two points. Basically they are the load-bearing walls of the building.

Creating a slope angle

The required slope angle is achieved in several ways:

When developing a building project, one of the walls on which the rafter legs will rest is made a little higher. This method is common, as it greatly simplifies the design of the rafters. But in this case, more material will be used to build walls. The side walls, running parallel to the rafters, are shaped like a trapezoid.
This method is variation 1. The frame racks are also taken into account when planning. In this option, the outer racks are higher on one side, and on the other they are lower by a certain height.
If the walls are of the same height, they are installed on one of the walls. vertical racks required height. At first glance, this design is unstable, since the rafter triangles have free movement to the right and left. But this fragility of the structure is eliminated when installing frame sheathing and wood sheathing of the front part of the roof.
Shed trusses can be used. This method is quite good in that you can build one truss, adjust it to required sizes and use it as a template. And using the template, you can build the rest of the trusses on the ground. There are ready-made roof trusses. They are ideally suited for any type of roof. For them, it is enough just to install and secure it to the Mauerlat. Next, you can freely sheathe the pitched roof with sheathing.
When constructing an extension near a house, this method is used. In this case, on one side of the extension, racks or a wall can be planned, and on the other, we already have a permanent wall of the finished building. Fastening to it can be done using a well-fixed horizontal purlin or separate fastenings, also aligned horizontally. All fastenings on the wall of the building are made above the racks or wall of the opposite side.

Determining the side of the roof slope

The question often arises, in which direction should the roof slope be determined? In the case of an extension to a house special options No. The slope is made in the direction from the building to ensure free flow of water during rainstorms.

If a separate building is planned, then you can choose a side. Basically, the location of the ramp is made on the back of the building. Although there are cases when the slope is made on the front side. In such a situation, the choice is based on the design style of the building, the territorial features of the site, which side is more convenient to lay the communications system, and the like.

But in this case, you should also not miss some nuances:

It would be more correct to position the pitched roof in the windy direction. In this way, the influence of wind is minimized. After all, wind directed at a roof at a slight angle has practically no effect on it.
For a rectangular building, you can choose the location of the slope along or across. But here you need to remember that the rafters of a pitched roof cannot have an unlimited length. For a certain distance they need to be strengthened. According to the rules, the free size of the rafters is 4.5 meters. When installing a rafter system up to 6 meters, a rafter leg is required. It is placed at an angle of 45 degrees on the support beam.

Steepness of slopes

If we are talking about a pitched roof, then in most cases the angle chosen is not up to 30 degrees. This choice is explained by the fact that the roof is highly vulnerable to wind loads on the front side of the building. Although they try to build the slope of the slope on the windy side, this does not exclude the presence of wind from the side of the facade. Therefore, a steep angle of inclination creates high strength rise. In strong winds, a high load is placed on the roof structure.

A slope below 10 degrees is also unacceptable, since the load on the rafter system immediately increases during snowfall. With the onset of a thaw, an ice crust appears on the edge of the roof, preventing the free flow of melt water.

It is important to determine the angle of the slope material roofing. After all, for different materials the manufacturer also indicates their own slope angle.

Depending on the material, some standard slope angle values can be distinguished:

Up to 2 degrees – almost flat roof. It requires at least 4 layers of rolled bitumen coating. It must be applied using hot technology. A gravel layer embedded in mastic is also required.
3-5 degrees - involves three layers of roll coating. Gravel powder may not be used.
9-15 degrees – with rolled material, 2 layers are enough. You can also use some types of corrugated sheets or metal tiles.
10-17 degrees - you can lay wavy slate with a reinforced profile.
11-20 degrees – soft bitumen shingles.
14-25 degrees – asbestos cement slate, at 25 degrees, corrugated sheets and metal tiles lie down with virtually no restrictions.
27-50 degrees – ceramic, cement tiles.

Installation

When building a pitched roof with your own hands, for correct and reliable installation you need to use drawings and detailed instructions, where all sizes and quantities will be indicated the required material. You can create a drawing diagram yourself or find a ready-made sample on the Internet. You can also order it from construction professionals.

Before starting construction, you need to choose a ventilated or non-ventilated roof type. The first is excellent for living quarters, as ventilation provides a comfortable microclimate inside the building. All this is achieved with the help of spaces between waterproofing materials. The second type is suitable for constructing a terrace or storage area.

Construction of rafters for a pitched roof

The rafter system of a pitched roof involves a couple of popular methods of its installation:

Fastening the rafters of a pitched roof to load-bearing walls. In this case, the roof will be more economical and less lumber will be used for it. The load-bearing wall must be at the same height as the roof. Since the upper part of the rafter rests on it.
A triangular truss is constructed, which includes beams and posts. It will unite the structure of the rafters. With this method, you do not have to build a load-bearing wall to the height of the roof, but more wood will be used. This method is convenient because you can mount all the trusses below using a template.

When erecting rafters, additional supports and struts will be needed. The number of such complementary elements depends on:

The slope of the ramp.
Rafter weights.
The length of the junction of the roof and the wall.
Roof material.
Materials of the thermal insulation layer.

Rafter pitch

The distance between the rafters can be determined by the box on which the roof is erected. To ensure that the distance between the rafters is the same, the slopes on which the rafter legs rest are divided into equal sections. Depending on the materials being installed, some values can be distinguished:

For rafters made of timber, the pitch is from 1.5-2 meters.
When using paired boards, the distance between the rafters is 1-1.75 meters.
The use of single boards relies on a pitch of 0.6-1.2 meters.

The type of insulation also influences the distance between the rafters. It is recommended that the thermal insulation layer be firmly installed between the rafters. After installing the rafter system, you can move on to the Mauerlat. It will help distribute the load on the walls.

The nuances of installing the Mauerlat

Mauerlat is a complementary element to any roof. The lower edge of the rafter is installed on it. Its fastening is carried out to load-bearing wall or between the beams of a rafter system. To attach the Mauerlat, it is necessary to use reinforcement if the walls of the house are made of porous material, burnt wire if the walls are brick, anchor bolts for a wooden house.

To extend the service life of the Mauerlat, it is necessary to install it on a waterproofing layer.

Floor beams, their installation

In addition to the Mauerlat, some structures of pitched roofs require the installation of floor beams. The rafter legs rest on them. Such beams are mounted with a step similar to the rafter system. The rafters are always attached to the mauerlat using a saw. The gap between the rafters and the Mauerlat is reduced to a minimum.

When the rafter system is more than 4.5 meters, rafter legs are installed. They give strength and prevent deflection of the rafter beam. The installation location depends on the width of the spans. A pitched roof of a huge area, without exception, must include rafter legs. Otherwise, it risks breaking or collapsing.

You need to remember that if you increase the pitch between the rafters, you will have to reduce the pitch of the sheathing or make it continuous.

When installing a pitched roof, do not forget about some nuances:

You need to place the ramp on the windy side. To prevent the roof from being blown off by the wind.
When calculating the rafter system, you need to take into account climatic conditions. This is the amount of snowfall, rainfall, and wind strength. Uniform distribution of the load on the rafters will increase the service life.
Take overlap into account when calculating materials.
The smaller pitch of the rafters of a pitched roof allows them to withstand a higher load.

An example of a lean-to garage design

The walls are built from foam blocks. The first step is to install the Mauerlat. With a pitched roof, these are 2 beams laid on walls of different heights.

The step-by-step scheme for constructing the rafter system consists of:

We install 100x150 mm timber on the inner sides of both walls. We install it on roofing felt waterproofing material. This will be our Mauerlat. We fasten the Mauerlat using reinforced corners 90x90. For this we use dowels with a diameter of 14 mm.
We take a 50x200 mm board and install it on the mauerlat with a margin of 50-60 cm. The margin must exceed the planned dimensions of the cornice. Afterwards, everything unnecessary is cut off.
We mark further cuts on the board, the depth of which should not be more than 1/3 of the width of the board.
We mark the walls so that the last rafters do not touch them. Recommended distance is 4-5 cm.
Using the template we make the remaining rafters. We fasten with brackets or corners.
Taking into account the width of the overhang, we produce fillies. We install all the elements of the cornice so that there is a layer of waterproofing between the wood and the wall.
We cut off all the excess and attach a 25x100 mm wind board.

The simplest garage design diagram has been completed. The next steps will be to install the sheathing and roofing material.

In contrast to the gable version, a shed roof is used in the construction of residential buildings much less frequently, one might even say reluctantly. First of all, because of the external angularity and excessive simplicity. A residential building under such a roof does not look very attractive. An exception may be original design projects for cottages with several multi-level pitched roofs; they look very beautiful, but are quite complex and require considerable effort in practical implementation.

What is special about a pitched roof?

Such a system is simpler and more affordable to make with your own hands; it is quite simple to assemble for a garage or warehouse. Often a pitched roof is the simplest and most effective solution for arranging simple auxiliary or utility rooms, for example, for making a roof on a brick extension to a house.

The advantages of a pitched roof include the following:

The weight from the rafters and power trusses in the roof frame does not create bursting forces, as is the case with gable options;
The rafters of a shed roof, even with a large roof span, do not require the use of massive and thick timber, as for more complex two- and four-pitched options. The main part of the load is transferred by the rafter system to the floor beams and walls of the building using struts, racks or load-bearing support trusses made from ordinary 50-gauge boards;
The use of a pitched roof often becomes the only possible option if it is necessary to make an extension to the main wall of the house, as in the photo, or even to make a roof over the balcony.

Thanks to the minimum requirements for the quality and size of the lumber from which the rafter system of a pitched roof is constructed, and the simple installation of the rafters and roofing package, this method of arranging the roof is practically indispensable for the construction of any ancillary buildings.

Features of using a pitched roof

In addition to the listed advantages and simplicity of the device, the lean-to rafter system has its own specifics, which should be taken into account when planning roof parameters:

Advice! The most preferable way of arranging a pitched roof would be to attach it to the main wall of a finished building.

Rafter design for a pitched roof

There are three main ways to install roof rafters. In terms of the configuration of the rafters, they have a lot in common; the main difference lies in the method of compensating for vertical loads on the rafters.

Installation of a rafter system from short beams

With a span not exceeding 4.5 m, the rafters can be made of timber or boards with a cross-section of 50x100 mm and installed with support on the upper and lower rows of the Mauerlat. If the Mauerlat is laid in a niche below the upper edge of the wall, then the upper edge of the rafters is trimmed vertically, and the supporting surface of the board is sawed at an angle for support on the Mauerlat beam. In this case, the joint between the end of the rafter and the wall surface must be covered with an overhead cornice element.

If the rafter rests on a mauerlat laid on the upper plane of the wall, in this case the edge of the rafter beam is also sawn to support the beam, but the vertical cut of the end is made under the plane of the wall. After leveling the roof rafters vertical plane The cut is covered with film and sewn up with a board. In both cases, the rafter beams are sewn with staples or steel tape directly to the Mauerlat board.

The lower edge of the rafter can be installed against the masonry of the wall. To create an overhang, “fillies” can be sewn to the rafters, and the beam itself is rested against the corner of the mauerlat and fixed with a wire loop on the inner surface of the walls or ceiling boards. Typically, this option is used for roofing made of corrugated sheets or bitumen shingles, as in the figure.

Roof construction from long rafters

A more complex option for assembling a pitched roof is a system with a long span. With a ceiling length of up to 6 meters, it is enough to support the rafter beams with additional supports. The rafter leg is attached to the rafter board with a steel plate and self-tapping screws without insertion.

For spans longer than six meters, at least one intermediate support will be required on the internal wall or a reinforced beam in the ceiling. With a large span, there may be two or three intermediate posts. In this case, an additional purlin beam is laid transversely to the roof slope under the rafters, leveling the roof plane. Each girder is installed on a vertical stand and reinforced with rafter legs and a screed.

Installation of a simple rafter system on transverse truss frames

The most common scheme for constructing a frame from prefabricated rafters is the option with the support of rafter beams on prefabricated trusses. In previous versions, the installation and fastening of the rafters of a pitched roof was carried out on the basis of two walls of different heights. This provided certain advantages. Due to the high rigidity and strength of the brick walls, there were no problems associated with the occurrence of lateral shear forces when arranging the roof, so the structure of the pitched roof was designed only for vertical loads.

In practice, such ideal conditions arise only when making an extension to a finished brick wall capital building. Much more often it is necessary to assemble a pitched roof on a brick or cinder block box of a garage or bathhouse with the same height of all walls. In this case, the roof rafter system will be more vulnerable to shear forces from wind loads.

IN this option To assemble the roof frame, layered rafter beams are used, laid on two prefabricated trusses or frames. One of them is combined with the main gable of the building, the second truss is installed in the middle, on the main interior wall building. The entire roof structure is installed on a laid frame made of 50 mm boards, which acts as a mauerlat. The board is attached to the brick wall using wire, steel tape and fence dowels. The result is a strong and fairly flexible mount.

First, the first support frame is made. The first truss is assembled from vertical posts attached to the base of the Mauerlat using metal spacer angles. This is the most labor-intensive and critical moment of the work; it is required to align the upper support bar of the frame strictly with the horizon; this determines how smooth the roof slope will be.

Before you begin assembling the second frame, you need to assemble two reference rafters on the ground. As usual, long rafters are made by splicing two short ones using padding on top of the halves of the third piece. Both rafters are laid out along the edges, one end on the first truss, the other end on the Mauerlat board on the opposite side, and the angle of inclination of both rafters is carefully adjusted.

Next, guided by the height of the installed reference rafters, assemble the second supporting truss-frame located in the central part of the box. At the next stage, the pediment of the first frame is covered with a board, spacer beams and wind boards are installed, as in the photo. This will ensure high rigidity of both frames, even in strong head winds. This is the specificity of creating a roof on frames of increased rigidity.

Slab rafters are attached to the trim board using steel brackets and wire loops. If desired, you can use a bolted connection as a fastener for the rafter system. One of the advantages of layered rafters is the easy way they can be spliced together from two shorter boards. Most often, two parts of the rafter beam are laid on supporting truss frames, after which the two halves are simply nailed together. Each of the rafters is carefully aligned at two points - the middle support frame and the lower support point on the harness. Next, it remains to nail the 100 mm, laid and adjusted rafter beams.

Before lathing, the side gables of the roof are covered with boards. This gives the entire structure the necessary rigidity and strength. Some of the rafters are designed in the form of lower and upper overhangs. The end surfaces of the rafter boards are lined with a cornice board and the lower part of the celestial cornice is covered with clapboard. At the next stage, it is necessary to tie the rafters with sheathing boards, they are laid on the beams and nailed in a checkerboard pattern. All that remains is to lay the ceiling and roofing material.

Various options for mounting rafters on a pitched roof

In addition to the above option for assembling a frame under a pitched roof, in practice simpler and available methods fastening the rafter system.

For example, when assembling a garden house from timber, it is enough to simply lay the rafter beams with a certain pitch on the pediment and the top beam of the rear wall of the house. In this case, the rafters, in addition to the supporting structure for the roof, play the role of a rigidity element for the entire house.

The structure of a pitched roof is quite easy to assemble for wooden extension to a house made of timber. The upper edge of the slope is installed on a beam, which rests on vertical posts nailed to the wall of the house. From the photo you can see that the lower support beam for the roof rafters is installed on vertical posts, the entire structure is designed in the form of a frame with additional front stiffeners. Each of the rafters has a cut under the supporting surface of the load-bearing beams.

In some cases, for example, when attaching a garage to a main wall, you can use the ends of the ceiling beams to attach the rafters, as in the photo. In this case, the rafter is rigidly attached using a pair of steel angles to the protruding end part of the beam.

Conclusion

Installing rafters for a pitched roof is no more difficult than assembling a frame for a gable roof. If you have experience working with spatial structures made of wood, such as a garden house or a barn of your own construction, even a novice carpenter can make a roof for an extension to a house.

Bikrost TCH
Chimney for a brick stove in a bathhouse
Hip roof
Rafter system of a pitched roof

The single-pitched rafter system came to us from the USA and Europe. Residents using it noted its reliability and low cost, so the popularity of this type spread very quickly. Despite the fact that a small amount of wood was required to build one slope, few people dared to undertake such construction. The fact is that most developers considered such a system too simple for residential buildings, and the other part simply did not know how to build it, in order to prove the opposite. In this article I will try to explain to you how to easily and quickly create such systems and correctly select the pitch of the rafters of a pitched roof.

Basis of calculations

Despite its simplicity, one slope must meet all installation rules. After all, if you make serious mistakes, the roof covering will become deformed, which will inevitably lead not only to leaks, but also to the collapse of the entire roof.

For maximum stability roofing system It is necessary to pay attention to four components:

Reliability of fastening the rafter legs to the support beam and ridge;
Correct selection of auxiliary parts for the rafter system;
Durable lumber and auxiliary elements;
Rafter step.

Don’t think that by observing just four points you will achieve the most stable structure. To do this, you will have to use all known methods and technologies.

Values for calculations

You can’t perform calculations without knowing certain indicators, right? So before you start, you need to make sure you have four basic values.

Roofing material parameters

Rafter foot step

Rafter slope

In addition to all these indicators, the main task of any project is to calculate the maximum permissible load on the roof. It includes quite a lot of values and here is a list of elements whose mass is especially important in the calculation:

Rafter legs
Lathing
Roofing pie

If you are not in the construction industry, then you will have to remember that the calculation of the maximum roof load consists of two parts. The first takes into account all the materials used, and the second contains the snow load of your region. Its meaning is written in a special reference book, which you can easily find on the Internet.

But even this indicators will not be accurate, because you forgot about the wind load and the weight of the worker himself, who will carry out installation work and subsequent maintenance (repairs, cleaning).

When a construction organization develops a project, they use complex strength-of-material formulas, so if you don’t want to worry about it, you can use the recommendations of experienced people.

How to calculate the required distance between rafter beams

The distance between the rafters of a pitched roof largely depends on the pre-calculated maximum possible pitch. To determine this value, you will need to have the total load value, roof parameters and data on the wood of the rafter legs.

You can calculate the optimal pitch of the rafter leg using the following method:

First of all, you need to find the full length of the roof. This value should include any ends and overhangs;
We divide the resulting value by the maximum allowable distance between the rafters;
We round the answer up. This number will indicate the number of spans;
Next, take the roof length and divide it into spans. This way you will find the optimal step;
And to find the number of rafter legs, you need to add one to the spans.

This rule works for the vast majority of roofs, but there are also those that cannot be calculated in this way. If this is your case, you will have to get an additional rafter at one of the ends.

Rafter system depending on roofing covering

It's no secret that the greater the mass of the roof covering, the greater the number of rafter legs that need to be installed. Most manufacturers of this material indicate in the instructions for their product optimal quantity rafters and their sizes.

You should not blindly trust these instructions unless you live in the central part of Russia, because they were written specifically for this territory. Before developing a drawing, it is necessary to carefully study the prevailing winds and draw a kind of rose, which will serve as a guide for future construction.

It is worth noting that in regions of the country where a large amount of precipitation falls in the form of snow, it is best to create steep roofs with a slope of 35-45 degrees. This will provide quick natural gathering snow cover from the surface.

In most cases, the rafter system of private houses is created from logs with a diameter of 12 to 22 centimeters, timber or boards with thicknesses from 40 to 100 and widths from 150 to 220 millimeters.

Rafter system for corrugated sheets

Roofing corrugated sheeting is a fairly lightweight material and at the same time has good strength characteristics. Therefore, lumber can be used as rafter legs. large section, but with frequent steps: 0.6 - 1.2 meters. Roof slope should be at a slope of 12 to 45 degrees.

The required cross-section can be selected based on the span distance between the supports. If the distance is about 3 meters, then the cross-section can be 40x150 millimeters, at 4 meters this value increases to 50x180 millimeters, and at 6 meters it is necessary to use lumber with a cross-section of 60x200 millimeters.

By the way, the lathing also plays an important role in this matter. In the case where the rafter pitch is a decent value, you will have to use wider boards. For example, for a step of 0.6 meters you will need elements with a cross-section of 25x100 millimeters, and for 1.2 meters - 40x100.

Lathing for corrugated sheets is arranged discharged method, and the pitch of its elements should be 50-80 centimeters. However, these values may go beyond due to the characteristics of the roofing itself. You can also find tips on how to arrange these parts in the instructions included with the purchased material.

Rafter system for ceramic tiles

Ceramic tiles are a unique roofing covering. It is made of clay, which makes this material very heavy. Designed rafter systems must comply with the following requirements:

In the roofing industry, there are only 3 types of sheathing. One of them can be arranged at an angle of 12-60 degrees, and the other two at 20-45 degrees. As sheathing elements for clay tiles, you can most often see timber with a cross-section of 50x50 millimeters.

Rafters for metal tiles

Thanks to metal sheets have a significantly smaller thickness; you do not have to install a serious rafter system. Therefore, you can safely follow the advice and recommendations of roofing material manufacturers.

It’s worth saying a few words about the only nuance that will allow you to save some lumber. So, it lies in the fact that the minimum pitch of the sheathing can be increased to 1 meter. This is due to the size sheet material. When a metal tile is tripled, as a rule, it is supported by sheathing only in a few places, and with a rafter pitch of 0.6 meters, it is impossible to create an “economical” sheathing, so you have to change it along with the rafter system.

Rafter structure for ondulin

Today, ondulin has given way to more modern coatings, but despite this, developers whose roofs were laid with asbestos slate began to look this material as a profitable alternative. It is made on the basis of bitumen and fiberglass, is lightweight and of high quality.

The rafter system for ondulin must meet the following parameters:

The slope of the slope should be in the range from 5 to 45 degrees;
With a small slope, the pitch of the rafter legs should be minimal: 0.6 meters, and with a steeper roof this distance increases to 0.9 meters;
With a flat roof, say up to 10 degrees, it is necessary to arrange a continuous sheathing. To do this, it is best to use moisture-resistant plywood, OSB boards or edged board with a section of 30x100 or timber 40x50 millimeters.

As for the cross-section of the rafter legs themselves, it is selected according to the same rules as for corrugated sheeting.

Rafter system for corrugated asbestos-cement sheets (slate)

Surprisingly, everyone knows the roofing material called “slate”, because the vast majority of private houses are covered with this particular product. Due to its rigidity and components, this material has quite a significant weight, so it is necessary to follow the recommendations for the construction of the rafter system so that it does not collapse even before the start of operation.

The low tightness of the finished plane does not allow the use of slate with a slope slope of less than 22 degrees, this will lead to leaks. If you cannot find any recommendations for installing asbestos-cement sheets (which is unlikely), then you always have the right to use the instructions included with the ondulin;
The maximum possible slope of the rafters with a slate roof is less than 60 degrees;
The optimal pitch of the rafter legs is in the range from 0.8 to 1.5 meters. Here everything will depend on the load and cross-section of the lumber;
Usually, wooden system under slate requires a slightly larger section of legs than with a light roof. As an example, we can cite a situation where the pitch of the rafters is 1.2 meters. For the rafters you will have to take a beam with a section of 75x150 or 100x200;
As for the sheathing, its elements will also differ from the pitch of the rafter legs. If it is up to 1.2 meters, then a beam of 50x50 millimeters will do, and with a larger step - 60x60 millimeters;
The pitch of the sheathing beam should be selected so that one sheet is supported by 3 elements. The slate should extend 15 centimeters beyond the edges on both sides. For example, if we consider the standard dimensions of an asbestos-cement sheet (175 centimeters), then a lathing pitch of 80 centimeters can be used.

It's probably worth remembering that asbestos is harmful substance Therefore, when working with a material that contains its particles, safety precautions must be observed. Which states that the worker must have personal protective equipment with him.

Rafter system of one and two slopes

Recently, the pitched roof has become increasingly popular. This is understandable, because materials are only becoming more expensive, and you really want to save money. Thanks to a simple design this can be done. The rafter system of one slope is quite primitive. To do this, you just need to place the beams on the crown and secure them. Of course, do not forget about the insulating material.

The maximum slope of a pitched roof can be 30 degrees, and the span can be 6 meters (this rule applies to lumber). The most optimal slope is considered to be 15-20 degrees. At this angle, the wind load will not cause much harm, but the snow cover will cause some inconvenience. The solution to this problem may be to place your building “downwind”, which will allow it to remove snow mass from the roof naturally.

An alternative option for a single-pitched roof is a gable roof. It consists of a number of rectangles connected together using a Mauerlat and a ridge. One interesting fact is worth noting. When the shape of a triangle approaches an isosceles one, its rigidity increases. In this regard, with a roof slope of up to 60 degrees, it is possible to expand the pitch between the rafters.

But you shouldn’t play around with calculations, because this can lead to an increase in windage and consumption of lumber. The most optimal slope slope for gable system– 45 degrees.

If you decide to build the roof yourself, then you will probably need some tips that will not only make your work easier, but will also increase the service life of your roof as a whole.

Calculating the structure correctly is not an easy task, but even if it is done correctly, it can be damaged if it is fastened incorrectly. Therefore, when installing the rafter legs in their places, perform the work with all responsibility. To improve your skills, you can read information on the Internet, or invite a knowledgeable person to the site;
The pitch of the rafter legs should not affect the thermal insulation in any way. It is worth remembering that the slabs can change slightly in size. Take advantage of this and squeeze them in as tightly as possible. In a hardware store, there are standard sizes of insulation boards of 60, 80, 100 and 120 centimeters;
For most roofs with a slope of less than 45 degrees, it is necessary to include the worker's weight in the calculation. As for sharper roofs, this is not necessary; therefore, the pitch of the rafter legs can be reduced by 20%;
Take advantage of modern technology and calculate your roof using online calculators. All you need to do is enter the exact parameters;
You can find regulatory documents regarding wind and snow loads online or from construction workers;
Any wood used for construction purposes should be dried as much as possible. This will avoid its deformation in the future.

The roof of a building is one of the most important elements the entire building. If you start saving on the roofing pie, you will soon be faced with expensive repairs that will affect not only this area, but the entire building as a whole. Therefore, if you want to get the maximum service life from your comfort, then you should not use low-quality materials.

The construction of the roof truss system and the subsequent roofing are the most important stages in any construction. This is a very complex matter, involving comprehensive preparation, which includes the calculation of the main elements of the system and the acquisition of materials of the required cross-section. Not every novice builder will be able to design and renovate a complex structure.

However, often during the construction of house buildings, utility or utility structures, garages, sheds, gazebos and other objects, the special complexity of the roof is not required at all - the simplicity of the design, the minimum amount of costs for materials and the speed of work, which are quite feasible, come first for independent execution. It is in such situations that the rafter system becomes a kind of “lifesaver”

In this publication, the main emphasis is on calculations of a pitched roof structure. In addition, the most typical cases of its construction will be considered.

The main advantages of pitched roofs

Despite the fact that not everyone likes the aesthetics of a building over which a pitched roof is installed (although the question itself is ambiguous), many owners of suburban areas, when constructing buildings, and sometimes even a residential building, choose this option, guided by a number of advantages similar design.

Very little materials are required for a single-pitch rafter system, especially if it is being built over a small outbuilding.
The most “tough” flat figure is a triangle. It is this that underlies almost any rafter system. In a single-slope system, this triangle is rectangular, which greatly simplifies the calculations, since all geometric relationships are known to everyone who has completed high school. But this simplicity does not in any way affect the strength and reliability of the entire structure.
Even if the presenter self-construction the owner of the site has never encountered the construction of a roof before, the installation of a lean-to rafter system should not cause him excessive difficulties - it is quite understandable and not so complicated. Often, when covering small outbuildings or other adjacent structures, it is quite possible to do without not only calling a team of specialists, but even without inviting assistants.
When erecting a roof structure, the speed of work is always important, naturally, without loss of quality - you want to protect the structure from the vagaries of the weather as quickly as possible. In terms of this parameter, the pitched roof is clearly the “leader” - its design contains practically no complex connecting units that take a lot of time and require high-precision adjustment.

How significant are the disadvantages of a lean-to rafter system? Alas, they exist, and they also have to be taken into account:

An attic with a pitched roof is either not intended at all, or it turns out to be so small that one has to forget about its wide functionality.

Based on the first point, there are certain difficulties in ensuring sufficient thermal insulation of rooms located under a pitched roof. Although, of course, this can be corrected - nothing prevents you from insulating the roof slope itself or placing an insulated attic floor under the rafter system.
Shed roofs, as a rule, are made with a slight slope, up to 25–30 degrees. This has two consequences. Firstly, not all types of roofing are suitable for such conditions. Secondly, the significance of the potential snow load increases sharply, which must be taken into account when calculating the system. But with such slopes, the influence of wind pressure on the roof is significantly reduced, especially if the slope is positioned correctly - in the windward direction, in accordance with the prevailing winds in a given area of the area.

Another drawback, perhaps, can be attributed to very conditional and subjective - this appearance pitched roof. It may not be to the liking of lovers of architectural delights, they say, it greatly simplifies the appearance of the building. This can also be objected to. First, the simplicity of the system and the cost-effectiveness of construction often play a decisive role in the construction of auxiliary structures. And three times - if you look at the overview of residential building projects, you can find very interesting design options in which the emphasis is placed specifically on the pitched roof. So, as they say, there is no arguing about tastes.

How is a lean-to rafter system calculated?

General principles of system calculation

In any case, a shed roof system is a structure of layered rafter legs installed parallel to each other. The name itself, “layered”, means that the rafters rest (lean) on two rigid support points. For ease of perception, let us turn to a simple diagram. (By the way, we will return to this same diagram more than once – when calculating the linear and angular parameters of the system).

So, two points of support for the rafter leg. One of the points (IN) located above the other (A) on specific value exceeding (h). Due to this, a slope of the slope is created, which is expressed by the angle α.

Thus, as already noted, the basis for constructing the system is a right triangle ABC, in which the base is the horizontal distance between the support points ( d) – most often this is the length or width of the building being built. Second leg – excess h. Well, the hypotenuse becomes the length of the rafter leg between the support points - L. Base angle (α) determines the steepness of the roof slope.

Now let's look at the main aspects of choosing a design and carrying out calculations in a little more detail.

How will the required slope of the slope be created?

The principle of arranging the rafters - parallel to each other with a certain pitch, with the required slope angle - is general, but this can be achieved in various ways.

The first is that even at the stage of developing a building project, the height of one wall (shown in pink) is immediately set in excess h relative to the opposite ( yellow). The two remaining walls, running parallel to the roof slope, are given a trapezoidal configuration. The method is quite common, and although it somewhat complicates the process of building walls, it extremely simplifies the creation of the roof truss system itself - almost everything for this is already ready.
The second method can, in principle, be considered a variation of the first. In this case we are talking about frame construction. Even at the project development stage, it is built into it, then the vertical posts of the frame on one side are higher by the same amount h compared to the opposite.

In the illustrations presented above and in those that will be placed below, the diagrams are made with simplification - the Mauerlat running along the upper end of the wall, or the strapping beam on the frame structure is not shown. This does not change anything fundamentally, but in practice it is impossible to do without this element, which is the basis for installing the rafter system.

What is a Mauerlat and how is it attached to the walls?

The main task of this element is to uniformly distribute the load from the rafter legs to the walls of the building. Read the rules for selecting materials for the walls of the house in a special publication on our portal.

The following approach is practiced when the walls are of equal height. The excess of one side of the rafter legs over the other can be ensured by installing vertical posts of the required height h.

The solution is simple, but the design turns out, at first glance, to be somewhat unstable - each of the “rafter triangles” has a certain degree of freedom to the left and to the right. This can be easily eliminated by attaching the transverse beams (boards) of the sheathing and covering the rectangular gable part of the roof on the front side. The remaining gable triangles on the sides are also sewn up with wood or other material convenient for the owner.

rafter mount

Another solution to the problem is to install a roof using single-pitch trusses. This method is good because it is possible, after making calculations, to ideally assemble and fit one truss, and then, taking it as a template, make the required number of exactly the same structures on the ground.

This technology is convenient to use in cases where, due to their large length, they require a certain amplification (this will be discussed below).

The rigidity of the entire rafter system is already inherent in the design of the truss - it is enough to install these assemblies on the mauerlat with a certain pitch, secure it to it, and then connect the trusses with strapping or transverse sheathing beams.

Another advantage of this approach is that the truss serves as both a rafter leg and a floor beam. Thus, the problem of thermal insulation of the ceiling and lining of the flow is significantly simplified - everything for this will be immediately ready.

Finally, one more case - it is suitable for the situation when a pitched roof is planned over an extension being built near the house.

On one side, the rafter legs rest on the frame posts or the wall of the extension being built. On the opposite side there is the main wall of the main building, and the rafters can rest on a horizontal purlin fixed on it, or on individual fastenings (brackets, embedded bars, etc.), but also aligned horizontally. The attachment line for this side of the rafter legs is also made in excess h.

Please note that although there are differences in installation approaches single slope system, in all options there is the same “rafter triangle” - this will be important for calculating the parameters of the future roof.

In which direction should the roof slope be provided?

It would seem like an idle question, however, it needs to be decided in advance.

In some cases, for example, if there are no special options - the slope should be located only in the direction from the building to ensure the free flow of storm water and melted snow.

A free-standing building already has certain options to choose from. Of course, the option is rarely considered in which the rafter system is positioned in such a way that the direction of the slope falls on the façade (although such a solution is not excluded). Most often, the slope is organized backwards or to one side.

Here you can already take the external one as the selection criteria design decoration building being constructed, features of the site, ease of laying communications of the collection system storm water and so on. But you should still keep in mind certain nuances.

The optimal location of a pitched roof is in the windward direction. This allows us to minimize the wind effect, which can work with the lifting application of the force vector, when the slope turns into a kind of wing - the wind tries to rip the roof upward. It is for pitched roofs that this is of utmost importance. If there is wind blowing into the roof, especially at small slope angles, the wind impact will be minimal.
The second aspect of choice is the length of the slope: in case of a rectangular building, it can be placed along it or across it. It is important to take into account here that the length of the rafters without reinforcement cannot be unlimited. In addition, the longer the rafter span between the support points, the thicker the cross-section of the lumber used to make these parts should be. This dependence will be explained a little later, during the calculations of the system.

However, the rule of thumb is that the free length of the rafter leg should usually not exceed 4.5 meters. As this parameter increases, additional structural reinforcement elements must be provided. Examples are shown in the illustration below:

So, if the distance between opposite walls is from 4.5 to 6 meters, it will be necessary to install a rafter leg (strut), located at an angle of 45°, and resting from below on a rigidly fixed support beam (bench). At distances of up to 12 meters, you will have to install a vertical post in the center, which should rest either on a reliable ceiling, or even on a solid partition inside the building. The stand also rests on the bed, and in addition, a strut is also installed on each side. This is all the more relevant due to the fact that the standard length of lumber usually does not exceed 6 meters, and the rafter leg will have to be made composite. So in any case it will not be possible to do without additional support.

A further increase in the length of the slope leads to an even greater complication of the system - it becomes necessary to install several vertical racks, with a pitch of no more than 6 meters, supported on the capital walls, and with the connection of these racks with contractions, with the installation of the same struts both on each rack and on both external walls.

Thus, you should think carefully about where it would be more profitable to orient the direction of the roof slope, also for reasons of simplifying the design of the rafter system.

wood screws

What slope angle will be optimal?

In the vast majority of cases, when it comes to a pitched roof, an angle of up to 30 degrees is chosen. This is explained by a number of reasons, and the most important of them has already been mentioned - the strong vulnerability of the lean-to structure to wind loads from the façade side. It is clear that, following the recommendations, the direction of the slope is oriented to the windward side, but this does not mean that the wind from the other side is completely excluded. The steeper the slope, the greater the lifting force created, and the greater the load on the roof structure will experience.

In addition, pitched roofs with a large angle of inclination look somewhat awkward. Of course, this is sometimes used in bold architectural and design projects, but we are talking about more “mundane” cases...

A slope that is too gentle, with a slope angle of up to 10 degrees, is also not very desirable, for the reason that the load on the rafter system from snow drifts increases sharply. In addition, with the beginning of snow melting, it is very likely that ice will appear along the lower edge of the slope, impeding the free flow of melt water.

An important criterion for choosing the slope angle is what is planned. It is no secret that for various roofing materials there are certain “frames”, that is, the minimum permissible roof slope angle.

The slope angle itself can be expressed not only in degrees. Many masters find it more convenient to operate with other parameters - proportions or percentages (even in some technical sources you can find a similar measurement system).

Proportional calculus is the ratio of the span length ( d) to the height of the slope ( h). It can be expressed, for example, by the ratio 1:3, 1:6 and so on.

The same ratio, but in absolute terms and reduced to percentages, gives a slightly different expression. For example, 1:5 - this will be a slope slope of 20%, 1:3 - 33.3%, etc.

To simplify the perception of these nuances, below is a table with a graph-diagram showing the ratio of degrees and percentages. The diagram is fully scaled, that is, it can be easily converted from one value to another.

The red lines show the conditional division of roofs: up to 3° - flat, from 3 to 30° - roofs with a low slope, from 30 to 45° - medium slope, and above 45 - steep slopes.

Blue arrows and their corresponding numerical designations (in circles) show the established lower limits for the use of a particular roofing material.


№	Slope amount	Type of permissible roof covering (minimum slope level)	Illustration
1	from 0 to 2°	Completely flat roof or with an inclination angle of up to 2°. At least 4 layers of roll bitumen coating applied using “hot” technology, with a mandatory top coating of fine gravel embedded in molten mastic.
2	≈ 2° 1:40 or 2.5%	The same as in point 1, but 3 layers of bitumen material will be enough, with mandatory topping
3	≈ 3° 1:20 or 5%	At least three layers of bitumen roll material, but without gravel backfill
4	≈ 9° 1:6.6 or 15%	When using rolled bitumen materials - at least two layers glued to the mastic using a hot method. The use of certain types of corrugated sheets and metal tiles is allowed (according to manufacturer's recommendations).
5	≈ 10° 1:6 or 17%	Asbestos-cement corrugated slate sheets with reinforced profile. Euroslate (odnulin).
6	≈ 11÷12° 1:5 or 20%	Soft bitumen shingles
7	≈ 14° 1:4 or 25%	Flat asbestos-cement slate with reinforced profile. Corrugated sheeting and metal tiles - practically without restrictions.
8	≈ 16° 1:3.5 or 29%	Sheet steel roofing with seam connection of adjacent sheets
9	≈ 18÷19° 1:3 or 33%	Asbestos-cement wavy slate of regular profile
10	≈ 26÷27° 1:2 or 50%	Natural ceramic or cement tiles, slate or composite polymer tiles
11	≈ 39° 1:1.25 or 80%	Roofing made of wood chips, shingles, natural shingles. For lovers of special exoticism - reed roofing

Having such information and having outlines for the future roofing covering, it will be easier to determine the slope angle.

metal tiles

How to set the required slope angle?

Let's turn again to our basic scheme“rafter triangle” located above.

So, to set the required slope angle α , it is necessary to ensure that one side of the rafter leg is raised by the amount h. The ratios of the parameters of a right triangle are known, that is, determining this height will not be difficult:

h = d × tg α

The tangent value is a tabular value that is easy to find in reference books or in tables published on the Internet. But in order to simplify the task as much as possible for our reader, below is a special calculator that will allow you to perform calculations in just a few seconds.

In addition, the calculator will help solve, if necessary, the inverse problem - by changing the slope angle in a certain range, select the optimal value of the excess, when this particular criterion becomes decisive.

Calculator for calculating the excess of the upper installation point of the rafter leg

Specify the requested values and click the "Calculate the value of excess h" button

Basic distance between rafter support points d (meters)

Planned roof slope angle α (degrees)

How to determine the length of the rafter leg?

There shouldn’t be any difficulties in this question either - using two known sides of a right triangle, it won’t be difficult to calculate the third using the well-known Pythagorean theorem. In our case, applied to the basic diagram, this relationship will be as follows:

L² =d² +h²

L = √ (d² +h²)

When calculating the length of the rafter legs, one nuance should be taken into account.

With small slope lengths, the length of the rafters is often increased by the width of the eaves overhang - this will make it easier to mount this entire assembly later. However, with large lengths of rafter legs, or in the case where, due to circumstances, it is necessary to use material of a very large cross-section, this approach does not always look reasonable. In such a situation, the rafters are lengthened using special elements of the system - fillies.

It is clear that in the case of a pitched roof there can be two eaves overhangs, that is, on both sides of the building, or one, when the roof is attached to the wall of the building.

Below is a calculator that will help you quickly and accurately calculate the required rafter length for a pitched roof. If desired, you can carry out calculations taking into account the eaves overhang or without it.

Calculator for calculating the length of the rafter leg of a pitched roof

Enter the requested values and click the "Calculate rafter length L" button

Elevation height h (meters)

Basic length d (meters)

Calculation conditions:

Required width of eaves overhang ΔL (meters)

Number of overhangs:

It is clear that if the length of the rafter leg exceeds the standard dimensions of commercially available lumber (usually 6 meters), then you will either have to abandon the formation using rafters in favor of fillies, or resort to splicing the timber. You can immediately assess what consequences this will lead to in order to make the optimal decision.

How to determine the required rafter section?

The length of the rafter legs (or the distance between the points of their attachment to the Mauerlat) is now known. The parameter for the height of raising one edge of the rafter has been found, that is, there is also a value for the slope angle of the future roof. Now you need to decide on the cross-section of the board or beam that will be used to make the rafter legs and, in conjunction with this, the steps for their installation.

All of the above parameters are closely interrelated and must ultimately correspond to the possible load on the rafter system in order to ensure the strength and stability of the entire roof structure, without distortions, deformation or even collapse.

Principles for calculating distributed load on rafters

All loads falling on the roof can be divided into several categories:

Constant static load, which is determined by the weight of the rafter system itself, the roofing material, the sheathing for it, and in the case of insulated slopes - the weight of the thermal insulation, internal lining attic ceiling, etc. This total indicator largely depends on the type of roofing material used - it is clear that the massiveness of corrugated sheeting, for example, cannot be compared with natural tiles or asbestos-cement slate. And yet, when designing a roofing system, they always strive to keep this figure within 50÷60 kg/m².
Temporary loads on the roof caused by external causes. This is certainly a snow load on the roof, especially characteristic of roofs with a slight slope. Wind load plays a role, and although it is not so great at small slope angles, it should not be completely discounted. Finally, the roof must also withstand the weight of a person, for example, when carrying out any repair work or when clearing the roof of snowdrifts.
A separate group includes extreme loads of a natural nature, caused, for example, by hurricane winds, snowfalls or rains that are abnormal for a given area, tectonic tremors of the earth, etc. It is almost impossible to foresee them, but when calculating for this case, a certain reserve of strength of structural elements is laid down.

Total loads are expressed in kilograms per square meter of roof area. (In technical literature, they often operate with other quantities - kilopascals. It is not difficult to translate - 1 kilopascal is approximately equal to 100 kg/m²).

The load falling on the roof is distributed along the rafter legs. Obviously, the more often they are installed, the less pressure will be applied to each linear meter of the rafter leg. This can be expressed by the following relationship:

Qр = Qс × S

Qр— distributed load per linear meter of rafters, kg/m;

Qс— total load per unit roof area, kg/m²;

S— step of installation of rafter legs, m.

For example, calculations show that an external impact of 140 kg is likely on the roof. with an installation step of 1.2 m, for each linear meter of the rafter leg there will already be 196 kg. But if you install the rafters more often, in increments of, say, 600 mm, then the degree of impact on these structural parts decreases sharply - only 84 kg/m.

Well, based on the obtained value of the distributed load, it is no longer difficult to determine the required cross-section of lumber that can withstand such an impact, without deflections, torsion, fractures, etc. There are special tables, one of which is given below:

Estimated value of the specific load per 1 linear meter of rafter leg, kg/m					Section of lumber for making rafter legs
75	100	125	150	175	from round timber	from a board (timber)
					diameter, mm	board (beam) thickness, mm
						40	50	60	70	80	90	100
Planned length of rafters between support points, m						board (beam) height, mm
4.5	4	3.5	3	2.5	120	180	170	160	150	140	130	120
5	4.5	4	3.5	3	140	200	190	180	170	160	150	140
5.5	5	4.5	4	3.5	160	-	210	200	190	180	170	160
6	5.5	5	4.5	4	180	-	-	220	210	200	190	180
6.5	6	5.5	5	4.5	200	-	-	-	230	220	210	200
-	6.5	6	5.5	5	220	-	-	-	-	240	230	220

Using this table is not difficult at all.

In its left part, the calculated specific load on the rafter leg is found (with an intermediate value, the closest value is taken in the larger direction).

Using the found column, they lower down to the required length of the rafter leg.

This line on the right side of the table shows the necessary parameters of lumber - the diameter of the round timber or the width and height of the timber (board). Here you can choose the most convenient option for yourself.

For example, calculations gave a load value of 90 kg/m. The length of the rafter leg between the support points is 5 meters. The table shows that you can use a log with a diameter of 160 mm or a board (timber) of the following sections: 50 × 210; 60×200; 70×190; 80×180; 80×180; 90×170; 100x160.

The only thing left to do is to determine the total and distributed load.

There is a developed, rather complex and cumbersome calculation algorithm. However, in this publication we will not overload the reader with an array of formulas and coefficients, but will suggest using a calculator specially designed for these purposes. True, to work with it it is necessary to make several explanations.

The entire territory of Russia is divided into several zones according to the probable level of snow load. In the calculator you will need to enter the zone number for the region in which construction is taking place. You can find your zone on the diagram map below:

The level of snow load is affected by the angle of the roof slope - we already know this value.

Initially, the approach is similar to that in the previous case - you need to determine your zone, but only by the degree of wind pressure. The schematic map is located below:

For wind load, the height of the roof being erected matters. Not to be confused with the exceedance parameter discussed earlier! In this case, it is the height from ground level to the highest point of the roof that is of interest.

The calculator will ask you to determine the construction zone and the degree of openness of the construction site. The criteria for assessing the level of openness are given in the calculator. However, there is a nuance.

We can talk about the presence of these natural or artificial barriers to the wind only if they are located no further than a distance of no more than 30×N, Where N– this is the height of the house being built. This means that to assess the degree of openness for a building with a height of, for example, 6 meters, you can take into account only those features that are located no further than within a radius of 180 meters.

In this calculator, the rafter installation step is a variable value. This approach is convenient from the point of view that by varying the pitch value, you can trace how the distributed load on the rafters changes, and therefore choose the most appropriate option in terms of selecting the necessary lumber.

By the way, if the pitched roof is planned to be insulated, then it makes sense to adjust the rafter installation step to the dimensions of standard insulation boards. For example, if pitas will be used basalt wool size 600×1000 mm, then it is better to set the rafter pitch to either 600 or 1000 mm. Due to the thickness of the rafter legs, the “clear” distance between them will be 50÷70 mm less - and these are almost ideal conditions for the tightest fit of the insulating blocks, without gaps.

However, let's return to the calculations. All other data for the calculator is known, and calculations can be carried out.

A single-pitched roof type is rarely seen in private housing construction. Although, according to some, this is in vain, because installing a pitched roof is much easier than installing a gable roof. On the other hand, such a roof structure will not be able to retain heat in the room so well. That is why a pitched roof is most often used to build a garage, country house or barn.

True, if the thermal insulation work is done correctly, the structure may well be warm. In this case, a living room is built under a pitched roof. Let's look at the advantages of a pitched roof, what types of rafter systems exist, and how the design is calculated. In addition, we will look at how to install this type of roof.

Pros and cons of a pitched roof for a house

Beginners in the construction business will be pleased that such a lean-to structure is quite simple and can be made with your own hands. True, the work cannot be called the simplest, but with detailed instructions a pitched roof will be created. But before considering the design features of the roof, you need to find out its features and advantages. They are what characterize this type of roof.

Advantages of a pitched roof:

Economical. To install a roof, you do not need a lot of building materials, on which the bulk of the funds are spent.
Simplicity of the rafter system and the lean-to structure as a whole. Best for beginners. Installation will be easier than with a gable roof.
The building will have little weight. This means there is less load on the walls and foundation.
Thanks to this shape, a pitched roof perfectly resists wind loads, as well as the weight of snow that accumulates on the surface.
The angle of inclination can be very different, depending on the needs. It varies from 5° to 45°.
If you make the angle of a pitched roof small, it can be used for various purposes. For example, if this is a barn, then install a tank for heating the liquid. If this is a living space, then on a pitched roof you can create a wonderful place to relax. As an option, install solar panels as an alternative power source.
The versatility of a lean-to building. It is covered with almost any commercially available material. It all depends on the operating conditions and the selected angle of inclination.

Despite all its advantages, a pitched roof also has disadvantages. This is not surprising, since nothing is perfect, but it is better to be aware of the disadvantages and use them advantageously.

Disadvantages of a pitched roof:

the first concerns insulation. There is no more space with an air gap under the structure, so the issue of insulation should be taken more seriously. If you do not thermally insulate the structure, then in the summer the attic will heat up too much, and in the winter, on the contrary, it will become overcooled. In either case, the temperature (high or low) will be transmitted into the house. This will help eliminate this correct calculations and high-quality insulation;
when creating a ceiling immediately under the roof, made at a slight angle, the house will not have an upper air gap and an attic space. And in this case, the living space cannot be organized;
due to the slight slope, which reaches from 5 to 10°, snow and moisture will accumulate on the shed surface.

Despite all the obvious disadvantages, a pitched roof is an ideal option for creating a garage and other buildings on the site.

Calculation of a single-pitch roof structure

This is the first step before installing the rafter system. It is recommended to draw up detailed plan or a drawing that will be used as a guide during work. To create this diagram, you need to select the following data:

the total width of the roof structure, as well as the length of the spans that are formed between the load-bearing walls;
slope angle, desired or obtained;
length of a pitched roof;
selected roofing material;
what height and width are the load-bearing walls?

Note! When a shed roof is created for a barn, garage or country house, you can simply raise the front wall of the structure higher than the back.

As a result, the angle of the slope will depend on the height of the rise. The second option involves creating supports on which the purlin will be laid. The second method allows you to save building materials.

For drawings you need to know the following nuances:

The drawing of the future pitched roof must have all the necessary information about the elements. The dimensions, distances between them, fastening features, etc. are indicated. Below is an example of such a drawing of a pitched roof.

Choosing the angle of a pitched roof

The angle of the slope is chosen taking into account the fact that the resulting roof forms a triangle, one corner of which will always be right. The legs are the floor beams and the pediment part of the building, and the rafters are the hypotenuse. This can be clearly seen in this diagram.

The designations are as follows:

Lc is the length of the rafter used;
Lbc is our leg, indicating the height of the pediment from the floor beam to the roof plane;
Lсд - width of the building;
A - the selected or desired angle of the pitched roof.

Taking into account the basic values, it is possible to calculate all the parameters of a lean-to structure. There is a formula for this. The first is used when the width of the building and the planned height of the pediment are taken as a basis. In this case, the formula is as follows:

When you have decided on the angle of the pitched roof, then you need to calculate the future height of the pediment. For this the formula is as follows:

In this case, the length of the roof rafters is calculated as follows:

Note! This rafter length does not take into account the canopy from the rear or facade of the room.

The choice of slope angle is influenced by many criteria. The main one is the choice of roofing material. It is recommended to buy each of them for a particular angle of inclination. Here are recommendations for popular roofing materials:

To install corrugated sheets, the slope must be at least 8°.
When using metal tiles, you will need to make a roof with an angle of 30°.
To install slate, you need indicators from 20° to 30°.
As for rolled roofing materials (roofing felt, bitumen tiles and soft roofing), the angle of inclination should be 5-7°, no less.

Advice! For a roof without a heating system in an area where there is a lot of snow in winter, the ideal solution would be a shed roof with a slope of 40°, regardless of the roofing material. This way all precipitation will quickly disappear from it.

Types of truss system for a pitched roof

There are three options for creating a rafter system. The choice of design depends on the size of the room and its type.

Now that we have understood the design of the rafter system and learned its types, we can consider the process of creating a pitched roof.

Installation work to create a pitched roof

Having the drawings and the selected type of system in hand, you can start working. You will also need the appropriate tools and lumber. Installation of the rafter system is carried out as follows:

For safety, the building should be covered with beams. They are laid on the wall. To extend their service life, roofing felt is glued to the wall. It will protect the beams from moisture and rotting. You need to arrange the floor sticks in the same way as the rafters. Mounting pitch -500-800 mm.
The mauerlat is laid on top of the beams. This is a massive beam that will serve as a support. It is placed on the rear lower wall of the building.
To safely move on the roof, a flooring made of wooden planks. It's temporary.
Now we need to build the gable wall. It is made from the same material as the building itself. You can use lighter material. For example, if the walls are brick, then the pediment is raised using bars or boards.
The floor beams must be covered with waterproofing and embedded in the wall. The pediment rises to the selected height, according to the drawings.
The mauerlat can be fixed to the finished pediment. It turns out that the two Mauerlats are parallel to each other.
Markings are applied to the lower wall for fastening the rafter legs. The fastening elements themselves are fixed.
To firmly fix the rafter, based on the drawings, grooves are cut out on it. This a good option fastenings The grooves are in two places, at the top and bottom, to fit into the mauerlat. There are other methods of fixing the rafter leg, as shown in this photo.
After which the legs are fixed with special corners and fastenings. At the top of the pediment, the legs are screwed tightly. But the lower part is made depending on the selected truss system for a pitched roof. It can be rigidly fixed or made sliding.
There is a certain sequence for inserting rafter legs. First, the outermost elements of the rafter system are installed. A cord is stretched between them, serving as a guide and level for subsequent rafters. Do not forget that the pitch of the rafters corresponds to the pitch of the floor beams.
The rafters, which are already installed, are connected to the floor beams through racks, struts and other elements to give them stability. We talked about them above. Fixation is performed with metal corners and brackets.
Advice! If it is necessary to lengthen the rafters and extend them beyond the wall, then “fillies” are attached to the beams. This way you can protect the adjacent part of the structure from precipitation.
When the structure of the pitched roof is ready, you can begin insulation and creating a roofing pie.

The photo shows what layers a proper insulated pitched roof should consist of.

Placed between the rafters insulation material. He has to hang in there tough. Then a counter-lattice is made on top for ventilation. A waterproofing film is laid on the counter-lattice. It protects the insulation from moisture, which can ruin it.

As for the lathing for laying roofing material, it is selected depending on what kind of roofing material it will be. For example, a continuous sheathing made of boards or plywood is needed when installing soft tiles and other rolled materials. If metal tiles, corrugated sheets, slate, ondulin and other types of rigid roofing are used, then the sheathing is done staggered. The pitch depends on the roofing material.

And to protect the insulation from the inside of a pitched roof, you need to cover it with a vapor barrier film. Now we can say that the pitched roof is completely ready.

Note! If a pitched roof is made for a barn or other non-residential structure, then there is no need to insulate it. It's better to spend it for another purpose.

Conclusion

Creating a roof, whether gable or single-pitch, is a dangerous, labor-intensive and responsible process. That is why caution and strict adherence to the instructions for creating the structure are required. Only then can you achieve the best result.

Are you planning to build a roof, do you need a simple structure with good strength and reliability characteristics? In this case, a pitched roof would be an excellent option. It will make your house, garage, extension or other structure original in its own way. In addition, the rafter system of a pitched roof is easy to install. It can be done without any construction experience.

In this article

Why single-pitched

The roof structure of 1 slope has the following advantages:

When building on a pitched roof, you can use any type of roofing material. Because the angle of inclination can be very small, you can build an almost flat roof.
The windage of this design is much less than that of a gable one. This option can be used in areas with strong winds.
Ease of installation and operation. You can build it yourself.
Light weight compared to other types of roofing.
For a pitched roof, you can build slopes of several floors. This solution will add design to your home.
Construction of a pitched roof is the most economical and does not require much time.
In this design, water rolls off only on one side.
The roof is suitable for any type of construction.

Like any other structure, a pitched roof has several disadvantages:

With a small angle of inclination, the area of the attic space is minimal.
Has a less attractive appearance. What can be corrected with the imagination of a designer.

Design calculation

Creating a slope angle

The required slope angle is achieved in several ways:

When developing a building project, one of the walls on which the rafter legs will rest is made a little higher. This method is common, as it greatly simplifies the design of the rafters. But in this case, more material will be used to build walls. The side walls, running parallel to the rafters, are shaped like a trapezoid.
This method is variation 1. The frame racks are also taken into account when planning. In this option, the outer racks are higher on one side, and on the other they are lower by a certain height.
If the height of the walls is the same, vertical posts of the required height are installed on one of the walls. At first glance, this design is unstable, since the rafter triangles have free movement to the right and left. But this fragility of the structure is eliminated when installing frame sheathing and wood sheathing of the front part of the roof.
Shed trusses can be used. This method is quite good in that you can build one truss, adjust it to the required dimensions and use it as a template. And using the template, you can build the rest of the trusses on the ground. There are ready-made roof trusses. They are ideally suited for any type of roof. For them, it is enough just to install and secure it to the Mauerlat. Next, you can freely sheathe the pitched roof with sheathing.
When constructing an extension near a house, this method is used. In this case, on one side of the extension, racks or a wall can be planned, and on the other, we already have a permanent wall of the finished building. Fastening to it can be done using a well-fixed horizontal purlin or separate fastenings, also aligned horizontally. All fastenings on the wall of the building are made above the racks or wall of the opposite side.

Determining the side of the roof slope

The question often arises, in which direction should the roof slope be determined? In the case of an extension to a house, there are no special options. The slope is made in the direction from the building to ensure free flow of water during rainstorms.

But in this case, you should also not miss some nuances:

It would be more correct to position the pitched roof in the windy direction. In this way, the influence of wind is minimized. After all, wind directed at a roof at a slight angle has practically no effect on it.
For a rectangular building, you can choose the location of the slope along or across. But here you need to remember that the rafters of a pitched roof cannot have an unlimited length. For a certain distance they need to be strengthened. According to the rules, the free size of the rafters is 4.5 meters. When installing a rafter system up to 6 meters, a rafter leg is required. It is placed at an angle of 45 degrees on the support beam.

Steepness of slopes

If we are talking about a pitched roof, then in most cases the angle chosen is not up to 30 degrees. This choice is explained by the fact that the roof is highly vulnerable to wind loads on the front side of the building. Although they try to build the slope of the slope on the windy side, this does not exclude the presence of wind from the side of the facade. Therefore, a steep inclination angle creates a high lifting force. In strong winds, a high load is placed on the roof structure.

The roofing material is also important for determining the slope angle. After all, for different materials the manufacturer also indicates their own slope angle.

Depending on the material, some standard slope angle values can be distinguished:

Up to 2 degrees – almost flat roof. It requires at least 4 layers of rolled bitumen coating. It must be applied using hot technology. A gravel layer embedded in mastic is also required.
3-5 degrees - involves three layers of roll coating. Gravel powder may not be used.
9-15 degrees – with rolled material, 2 layers are enough. You can also use some types of corrugated sheets or metal tiles.
10-17 degrees - you can lay wavy slate with a reinforced profile.
11-20 degrees – soft bitumen shingles.
14-25 degrees - asbestos-cement slate; at 25 degrees, corrugated sheets and metal tiles fit almost without restrictions.
27-50 degrees – ceramic, cement tiles.

Installation

When building a pitched roof with your own hands, for correct and reliable installation you need to use drawings and detailed instructions, which will indicate all the dimensions and quantity of the required material. You can create a drawing diagram yourself or find a ready-made sample on the Internet. You can also order it from construction professionals.

Construction of rafters for a pitched roof

The rafter system of a pitched roof involves a couple of popular methods of its installation:

Fastening the rafters of a pitched roof to load-bearing walls. In this case, the roof will be more economical and less lumber will be used for it. The load-bearing wall must be at the same height as the roof. Since the upper part of the rafter rests on it.
A triangular truss is constructed, which includes beams and posts. It will unite the structure of the rafters. With this method, you do not have to build a load-bearing wall to the height of the roof, but more wood will be used. This method is convenient because you can mount all the trusses below using a template.

When erecting rafters, additional supports and struts will be needed. The number of such complementary elements depends on:

The slope of the ramp.
Rafter weights.
The length of the junction of the roof and the wall.
Roof material.
Materials of the thermal insulation layer.

Rafter pitch

For rafters made of timber, the pitch is from 1.5-2 meters.
When using paired boards, the distance between the rafters is 1-1.75 meters.
The use of single boards relies on a pitch of 0.6-1.2 meters.

The nuances of installing the Mauerlat

Mauerlat is a complementary element to any roof. The lower edge of the rafter is installed on it. It is fastened to a load-bearing wall or between the beams of the rafter system. To attach the Mauerlat, it is necessary to use reinforcement if the walls of the house are made of porous material, burnt wire if the walls are brick, and anchor bolts for a wooden house.

To extend the service life of the Mauerlat, it is necessary to install it on a waterproofing layer.

Floor beams, their installation

You need to remember that if you increase the pitch between the rafters, you will have to reduce the pitch of the sheathing or make it continuous.

When installing a pitched roof, do not forget about some nuances:

You need to place the ramp on the windy side. To prevent the roof from being blown off by the wind.
When calculating the rafter system, you need to take into account climatic conditions. This is the amount of snowfall, rainfall, and wind strength. Uniform distribution of the load on the rafters will increase the service life.
Take overlap into account when calculating materials.
The smaller pitch of the rafters of a pitched roof allows them to withstand a higher load.

An example of a lean-to garage design

The walls are built from foam blocks. The first step is to install the Mauerlat. With a pitched roof, these are 2 beams laid on walls of different heights.

The step-by-step scheme for constructing the rafter system consists of:

We install 100x150 mm timber on the inner sides of both walls. We install it on roofing felt waterproofing material. This will be our Mauerlat. We fasten the Mauerlat using reinforced corners 90x90. For this we use dowels with a diameter of 14 mm.
We take a 50x200 mm board and install it on the mauerlat with a margin of 50-60 cm. The margin must exceed the planned dimensions of the cornice. Afterwards, everything unnecessary is cut off.
We mark further cuts on the board, the depth of which should not be more than 1/3 of the width of the board.
We mark the walls so that the last rafters do not touch them. Recommended distance is 4-5 cm.
Using the template we make the remaining rafters. We fasten with brackets or corners.
Taking into account the width of the overhang, we produce fillies. We install all the elements of the cornice so that there is a layer of waterproofing between the wood and the wall.
We cut off all the excess and attach a 25x100 mm wind board.

The simplest garage design diagram has been completed. The next steps will be to install the sheathing and roofing material.

Do-it-yourself pitched roof - step by step with photos - for a house, barn, garage. Shed roof rafter system: design and installation features Shed rafter pitch

Hanging rafters

Layered rafters

Options for attaching rafters to the Mauerlat

Fixing the rafter leg

Types of fixation without gash and with its presence

Types of fasteners

Rules for carrying out work on fastening rafters

Alternative uses of fasteners

Rules for fastening

Conclusion

Why single-pitched

Design calculation

Creating a slope angle

Determining the side of the roof slope

Steepness of slopes

Installation

Construction of rafters for a pitched roof

Rafter pitch

The nuances of installing the Mauerlat

Floor beams, their installation

An example of a lean-to garage design

What is special about a pitched roof?

Features of using a pitched roof

Rafter design for a pitched roof

Installation of a rafter system from short beams

Basis of calculations

Values ​​for calculations

How to calculate the required distance between rafter beams

Rafter system depending on roofing covering

Rafter system for corrugated sheets

Rafter system for ceramic tiles

Rafters for metal tiles

Rafter structure for ondulin

Rafter system for corrugated asbestos-cement sheets (slate)

Rafter system of one and two slopes

The main advantages of pitched roofs

How is a lean-to rafter system calculated?

General principles of system calculation

How will the required slope of the slope be created?

In which direction should the roof slope be provided?

What slope angle will be optimal?

How to set the required slope angle?

Calculator for calculating the excess of the upper installation point of the rafter leg

How to determine the length of the rafter leg?

Calculator for calculating the length of the rafter leg of a pitched roof

How to determine the required rafter section?

Principles for calculating distributed load on rafters

Pros and cons of a pitched roof for a house

Calculation of a single-pitch roof structure

Choosing the angle of a pitched roof

Types of truss system for a pitched roof

Installation work to create a pitched roof

Conclusion

Why single-pitched

Design calculation

Creating a slope angle

Determining the side of the roof slope

Steepness of slopes

Installation

Construction of rafters for a pitched roof

Rafter pitch

The nuances of installing the Mauerlat

Floor beams, their installation

An example of a lean-to garage design

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You need to know this

Values for calculations