How to assemble a roof frame. Making a roof frame with your own hands

Which beautiful roofs at modern houses! Even a non-specialist can see that they are among the most different materials, and the fact that they have a variety of shapes and colors is visible to the naked eye. When the roof of a house is being erected, a properly constructed frame for the roof is very important. If it is built with defects, incorrectly calculated, or the wrong material is used, the roof will “sink” very soon. After all, the frame bears a huge load, and its task is to withstand it, to make the roof a reliable and durable protection for our home.

The task of erecting a frame is quite difficult, but not impossible; even a novice master should not panic. The design of the roof of the houses is being chosen, and their offer is huge, you need to decide and boldly get to work.

If the house is not very large, and the person has prepared well theoretically and calculated everything correctly, he will be able to build the frame for the roof alone, without helpers, with his own hands.

This is very good option in the sense of large savings in funds that would have been spent on payment work force. In addition, a person is confident in the quality of the work he does independently; who can do better than for himself? In this case, you can be sure of good quality frame and don’t expect any less than pleasant surprises from the roof in the future.

Let's try to tell you how to make a high-quality roof frame yourself, what tools you will need, what materials are best to use. We will try to ensure that both the tools and materials are the simplest and most common.

Roofs come in the most different designs, more or less difficult to implement. Can be called hip roofs, broken, single-pitched. We will consider a gable roof, it is the most common. In addition, having mastered the technology of building a certain type of frame, it will be easy to move on to another, taking into account, of course, some of its features.

Choosing the type of rafter system

There are different rafter systems, but this is what you need to decide first, choose which one will be used. All these systems consist of two rafter legs. At the top of the frame they are connected to each other. At the bottom they are also connected, for this there is a bottom tie. This screed can be the basis for attic floor. As in any business, there are some nuances here.

Rafter systems can be layered or hanging. In the construction of a private house, both one and the other systems are possible.

How to choose a system for constructing a frame?

Choice rafter system depends primarily on what kind of house is being built and its size. A hanging system is installed if the distance between two load-bearing walls is not very large, no more than 6 meters, that is, the house is small. With this system, if the building is large, the rafters may sag under their own weight, since their legs rest on the side walls and nothing more.

IN big house you need to use a layered system, it is much more reliable. In this case, the house must have an internal load-bearing wall in the center. Another support is installed on it, which will prevent the rafters from sagging.

Choosing materials for the frame

Let's see what we need to purchase in order to build the frame ourselves gable roof.

The rafters are made of wood. This is the most important element during the construction of the frame. Need edged board(50x150 mm), you will also need timber (150x150 mm).

The most good wood coniferous, especially if it was harvested in winter. It’s great if the resin hasn’t been drained from it first. Resin serves as a natural antiseptic and will extend the life of wood for many years. It is important how the tree was stored before sale and how dry it was. In general, already at this stage you need to be very careful in order to buy quality material. It is necessary to carefully inspect the wood so that in no case are there woodworms or their traces, there are no cracks or other defects.

In general, only high-quality material is purchased, the rest is mercilessly rejected as unsuitable for constructing a frame for the roof of a house.

Should know, What wooden frames not the only ones in nature. Roof frames made of metal channels are also possible, or reinforced concrete are possible. The roof with such frames is very heavy, it is impossible to build it yourself. That is, only a wooden frame is suitable for DIY work, which is what is being considered.

The roof frame consists of rafters, purlins, racks, attic floors, counter battens and sheathing. Each element has its own task and purpose.

The attic space can be an ordinary attic, a warehouse for unnecessary things, or it can be thought of as an attic, additional area Houses. So, if this is a simple attic, 50x150mm boards are suitable for the attic floor. For an attic, it is clear that the flooring must be much stronger; a board cannot be used here. You need timber 150x150 mm. It gives quite sufficient strength. Place it directly on the Mauerlat.

The timber for the sheathing must be strictly straight. You need to keep an eye on this when purchasing it. The slightest error will significantly complicate roofing. So this condition of straightness of the beam is important.

Lathing and counter-lattice can be made not only from timber. A material such as a perforated galvanized iron profile is also perfect.

In addition to the materials actually used for the rafters, both sheathing, ceilings, some other things are needed.

1. To attach the support beam, called the Mauerlat, you need threaded metal studs.
2. The rafter legs are attached to the mauerlat using staples and brackets, therefore, they are also needed.
3. The rafters also need to be connected to each other. This is done using various fasteners, such as wood screws, studs of different diameters - 8 and 10 mm.
4. You need galvanized nails.

The tools for the job are quite common - these are hammers of different sizes, you will need different ones, and a drill to drill holes. You need a grinder or a saw to cut the rafters to size and give them the required shape. Needed carpenter's ax, planes. All this is often found in a man’s toolbox at home. So there is no need for new acquisitions, everything is simple.

A measuring tool is a must. These are a level, a plumb line and a tape measure. In the construction of the roof frame, everything must be very precise, no “by eye”.

Frame wood protection

All wooden parts of the future frame must be protected from possible fire and rotting. This must be done before starting construction, erecting rafters, and so on.

There are two compositions that must be used to process all the details of the future building - rafters, sheathing and others. It is an antipyretic and antiseptic.

The first substance significantly reduces the flammable properties of wood, which dramatically reduces the possibility of fire.

Secondly, it kills bacteria, which prevents putrefactive processes from developing in the wood.

To apply the compositions, it is recommended to use a brush; it gives a better result than a spray. The sprayer does not provide deep impregnation. Each composition is applied in layers, let the layer dry, after which the next one is applied.

Please note! Some protective compounds are toxic to one degree or another. It's better to work outside. If indoors, it should be well ventilated. Goggles and a respirator are required, that is, means personal protection.

Protection of the roof frame is possible even after its construction.

Sometimes protection from fire and bacteria is carried out after the construction of the frame. It's worse, but possible. It is clear that the brush is used to process wood in an already constructed structure. You need to pay very close attention to the places where the beams are connected; they need to be impregnated especially carefully.

So, with the chosen type of rafter system, purchased and prepared material, you can begin construction directly.

Installing the Mauerlat

The wooden beam that is laid on the load-bearing walls of the house and which will serve as a support for the frame of the future roof is called Mauerlat by builders. It transmits and distributes loads arising from the weight of the roof, from external influences (wind, snow, rain), to bearing structures Houses. Roof only frame house or for a house made of timber, a mauerlat is not needed, where the upper wall beam plays its role. In other systems, the Mauerlat is necessary; it is the basis of the rafter system.

It is recommended to use timber for the Mauerlat. It can be 100x150, 150x150 is also possible. WITH inside They try to lay the Mauerlat buildings “flush” with the surface of the house, and a brick barrier is erected from the outside at the level of the Mauerlat. A concrete pavement is laid around the perimeter of the building. After it dries, roofing material is laid on it in several layers. This is to ensure waterproofing. In addition, roofing felt will prevent moisture from concrete from getting into the wood.

Most often, the Mauerlat is laid using the following technology:

1. Metal studs with a diameter of more than 10 mm are installed in the concrete. The studs can be installed when the blind area is dry. To do this, you will need to drill holes in the concrete and secure the installed studs with fresh mortar. It is better to foresee this in advance and install the studs in the newly poured blind area. Of course, this method is more profitable, we will save time, we will save labor.
2. A solid beam for the mauerlat is laid along the blind area, and the locations of the already installed studs are marked on it. Holes are drilled along these marks. The diameter of the drill must match the diameter of the studs. After this, the Mauerlat is put on the studs. The studs should stick out from the timber by 15 centimeters.
3. The Mauerlat is secured to the studs with nuts. Wide washers must be placed under the nuts. They save the wood from damage when tightening the nut.

Please note! If you have the skills of a welder and a welding machine, you can do without studs, saving on them. Their role is perfectly played by reinforcing bars, and the nuts are welded to these bars.

There is another simpler way of laying the Mauerlat, which makes the work easier. In this case, not timber is used, but two layers of boards.

1. The boards of the first row are laid around the perimeter of the building. They are fastened with countersunk anchor screws and a metal sleeve. You need a hammer drill to drill holes in concrete or brick. The board is pre-drilled with a drill.
2. The boards of the second row are laid on the first. The joints of the boards should not match. In the corners, the boards are laid “in a bandage”.
3. The rows are connected using large (100mm) nails.

The main relief of such installation is the simpler lifting of the material, the boards are lighter than the beams. The strength of such a structure does not suffer much compared to a timber structure. She is enough. Especially if the house is frame.

Installation of rafters

The next stage after the Mauerlat is the installation of rafters. It is recommended to carry out all processing of rafter beams on the ground. This is especially true for single masters. On the ground it is more convenient to give the rafters right size, using a template, give the desired shape, make the grooves and holes necessary for fastening. Next, the rafters (their parts) rise to the top, and work on fastening them can begin.

Let's look at how a roof with a hanging rafter system is built and its technology.

To install the rafter legs, grooves are cut in the Mauerlat. The distance between the rafter legs is determined individually at the stage of thinking through the project, but it is not less than 1.5 meters. Anything less is impossible, the structure will be insufficiently strong.

Please note! When planning roof insulation, the distance between the rafters must be linked to the amount of insulation. This will help save time on cutting the latter, since entire sheets of it will be laid.

The rafters are installed with end sides roofs, that is, from the gables. When the rafters are installed at the ends, a cord is pulled from ridge to ridge. They are guided by it when installing the remaining rafters - intermediate ones.

The rafter legs are inserted into the grooves and fixed. For this, complex fasteners are used. The steel bracket will limit the transverse movement, and the brackets will limit the longitudinal movement. This bracket secures the rafter to the mauerlat.

The rafters must extend beyond the perimeter of the house; this must be remembered when installing them. The overhang (or overhang) of the rafters is considered normal by 40 centimeters. This overhang will protect the walls of the building from rain, from water flowing abundantly down the roof of the house. This overhang of the rafters is necessary; it can also be increased by adding a thin board, which is called a “filly”. The “filly” is attached to the rafters with nails, using a spacer - a piece of board.

Please note! “Filly” makes it possible to make the structure of the roof frame lighter and cheaper. This is in no way a defect or shortcoming. In addition, this makes it easier to repair the overhang. You can replace a “filly”, two “fillies” - it’s still easier than changing the rafter beam.

1. The lower parts of the rafters are fixed with strapping. This strapping is used as a base for the attic floor. Mauerlat is a support for the beams of this harness.
2. If the length of the rafter beam is insufficient, it is increased. Two beams are laid overlay, and the overlap must be at least a meter, otherwise the strength will be low. The bars are fixed with pins. Their diameter is at least 8 mm.
3. The rafters are connected to each other by pins. Holes are pre-drilled for them. To prevent the rafters from rotating and to be firmly fixed, they are connected with two studs at once.
4. If the roof is no more than 6 meters wide, the hanging rafters are connected by a cross beam. It's called a puff and is shaped like the letter "A". Tightenings are made from boards 50x100 or 50x150, they are attached to the rafters with self-tapping screws. Sometimes tie-ins of three 30x100 boards are installed; they are placed on both sides of the rafters.
5. At the top of the rafter trusses, they are fixed with a longitudinal ridge beam, sometimes with a ridge board.
6. To strengthen the rafter assembly from above, sometimes a ridge beam is connected to a tie. For this, a piece of board is used. This is especially necessary when there is a large distance between the rafters. With such a connection there will be no deflection of the tightening.

These operations are repeated for all rafter pairs. When this difficult work is completed, the rafters are installed, you can begin the sheathing.

Lathing

The type of sheathing will depend on the type of roofing material and roof rafters - whether it will be solid or thinned. For laying soft and rolled roofing materials continuous sheathing is required. For its manufacture, fairly thick (at least 10mm) moisture-resistant plywood or OSB boards. The sheets are stuffed onto the rafters through a counter-batten.

If thinned sheathing is being erected, beams or boards are placed onto the rafters for the roof with your own hands. The board can be unedged if strict economy is necessary. The size of the roofing material determines the distance between the boards or beams.

Fill the thinned sheathing from top to bottom. The first rows from the ridge are filled without a gap. This is done for greater strength.

After this work is completed, the roof is insulated and waterproofing is installed. Roofing work can begin.

Of course, the process of building a frame for a roof cannot be called simple matter. But if you approach the matter seriously, weigh everything, study it, think it through, success will certainly come.

When erecting a roof, the “first fiddle” in the entire structure is played by the roof frame. It is the frame that bears the main mechanical load, which means that the highest demands are placed on the strength, reliability and durability of the frame. The roofing material, insulation and waterproofing can be very different, but if the frame is built with flaws - good luck: such a roof will not last long.

Very often, the construction of a roof frame confuses novice craftsmen. However, if you look at it, there is nothing impossible in this task; you just need to choose one of the proposed ones and get down to business.

With the proper approach, correct calculations and good theoretical preparation, the frame part of the roof for a small house can be erected even alone.

At the same time, you will not only significantly save financial resources that would inevitably be spent on paying hired craftsmen, but you will also be able to control the process of constructing the frame.

And this, in turn, means that the design of your roof will not present you with unpleasant surprises at the most inopportune moment.

In this article we will tell you how to make a roof frame yourself, using only the most common tools and materials.

For example, we will take the frame of the most common gable roof type. But if you master this technology, then you can easily build roofs of other designs (hipped, pitched, pitched) - you just need to take into account the features of a particular design.

The first thing we need to decide on is the type of rafter system. Any rafter system consists of two rafter legs connected to each other at the top.

In the lower part, the legs are connected by a lower screed, which can also serve as the basis for the attic floor. However, there may be nuances in the structure of such a system.

The frame of the roof of a house can be built on the basis of two types of rafter systems: layered and hanging. Both layered and hanging system rafters can be used in private construction.

How to choose a system for constructing a frame?

The choice of rafter system is determined mainly by design features the building itself. If the distance between the external load-bearing walls does not exceed 6 m, a hanging rafter system can be installed.

The peculiarity of this system is that the rafter legs rest only on the side walls of the house - and with a large building width, a rather dangerous sagging of the building rafters occurs under their own weight.

A more reliable layered system is used when the distance between external load-bearing walls exceeds 6 m, but in the room itself there is an internal load-bearing wall located in the center of the building.

In this case, you can avoid sagging rafters by installing additional support.

Choosing materials for the frame

What do we need to independently build a gable roof frame?

The rafters - the key component of the frame - will be built from wood. To do this, we need to purchase a 50x150 mm edged board, as well as a 150x150 mm timber.

It is optimal if the wood is coniferous, harvested in the winter, and one from which the resin has not previously been drained (the resinous substances in the wood significantly extend its service life, acting as a natural antiseptic). The conditions in which the wood was stored before purchase and the degree to which it was dried are also very important.

When inspecting boards and beams, it is necessary to pay attention to possible wood defects: delamination, cracks, traces of damage from woodworms.

Materials on which these signs are found must be rejected - their use in the construction of a roof frame is unacceptable.

Note! Roof frames can be made not only from lumber, but also from metal channel or reinforced concrete structures. But in this case the roof turns out to be quite heavy, and we are talking about it self-construction no longer works.

In addition to the rafter legs, purlins and racks that make up the rafter system, the design of the roof frame includes an attic floor, as well as counter-lattice and sheathing.

If attic space will be used for its intended purpose (i.e. as an attic or warehouse), then a 50x150 mm board is sufficient for the construction of an attic floor.

If attic space will act as an attic (i.e. living space), then the floor must be more durable: to lay it we will need a 150x150 mm beam, which is laid directly on the mauerlat. The use of such timber allows you to achieve sufficient strength from the attic floor.

For the sheathing and counter-lattice we use thinner timber. Timber is quite suitable square section 40x40 or 50x50 mm. Beams of this thickness are strong enough to support the weight of almost any roofing material.

When choosing beams for sheathing, you need to strictly monitor their straightness, because the slightest deviation from a straight line can significantly complicate roofing work.

Also, for the construction of lathing and counter-lattice, a perforated profile made of galvanized iron can be used.

In addition to materials for the construction of rafters, floors and sheathing, we will need:

• Threaded metal studs for attaching the Mauerlat (support beam)
• Brackets and brackets for attaching rafter legs to the Mauerlat
• Fastening elements (wood screws, studs with a diameter of 8 and 10 mm) for connecting the rafters to each other
• Galvanized nails

The set of tools required to build a roof frame is quite standard: you will need hammers different sizes, a drill for drilling holes, a saw (or grinder) for cutting rafters to size and giving them the desired shape, a carpenter's axe, planes - in general, everything that is already very likely to be found in your tool cabinet.

Particular attention should be paid to the measuring tool, because without an accurate level, plumb line and tape measure, you are unlikely to be able to align the rafters exactly at a sufficiently large distance.

Frame wood protection

Before proceeding with the construction of the rafter system, it is necessary to provide all wooden parts of the roof frame with protection from fire and rot.

To do this, all parts of the rafters, ceilings and sheathing must be treated with two compounds:

• Antipyretic - a composition that reduces the flammability of wood and protects the wooden part of the roof frame from fire
• Antiseptic – a substance that kills bacteria and prevents the occurrence of putrefactive processes in the wood of rafters and ceilings.

Note! Some wood preservatives are quite toxic. Therefore, they should be applied only in a well-ventilated area or outdoors, and use personal protective equipment (goggles and a respirator).

Protection of the roof frame is possible even after its construction. In this case, we already treat it with a fire-retardant and antibacterial composition. installed structure, paying special attention to the impregnation of wood at the junction of the beams of the rafter system.

So, the type of rafter system has been selected, the materials have been purchased and processed protective composition. It's time to start building the rafter system.

Installing the Mauerlat

The support for the frame of our future roof is the Mauerlat - wooden beam, which is laid on the load-bearing walls of the house. The main function of the Mauerlat is to transfer and distribute the weight of the roof and the resulting loads (wind, snow, etc.) onto the supporting structures.

Mauerlat is the basis for almost any rafter system. An exception may be the roof of a house made of timber or the roof of a frame house - when building the frame with your own hands, in these houses you will use the upper wall beam instead of the mauerlat.

Most often (with the exception of the option that will be described below), 100x150 or 150x150 mm timber is used as a Mauerlat. It is optimal if the Mauerlat is laid “flush” with the inner surface of the building wall, and a brick barrier is erected outside at the level of the Mauerlat.

To lay the mauerlat along the perimeter of the building, we lay a monolithic concrete blind area. After the concrete has completely dried, we lay several layers of roofing material on it - it will provide a sufficient level of waterproofing and will effectively prevent the wood from absorbing moisture from the concrete base.

Most often, the Mauerlat is laid using the following technology:

• IN concrete base we install studs from a metal rod with a diameter of 10 mm or more. Studs can be installed as during construction concrete blind area, and later - by drilling holes in the concrete and securing pins in the holes cement mortar. The first method is preferable because it is less labor-intensive.
• Mauerlat from solid timber We lay 150x150mm along the blind area, and make marks in places where the timber touches the studs. Using the marks, we drill holes with a drill whose diameter corresponds to the diameter of the studs. We put the Mauerlat on the studs, and the studs should protrude from the timber by at least 10-15 mm.
• We fix the mauerlat on the studs using nuts, placing a wide flat washer between the beam and the nut to avoid damage to the wood when the nut is tightly tightened

Note! If you have a welding machine at hand and you have the skills to work with it, you can save on studs. In this case, instead of studs, we use reinforcing bars, and simply weld the fixing nuts to them.

Another method of laying the Mauerlat makes the work somewhat easier.

Instead of timber, you can use two layers of 50x150 mm boards:

• We lay out the first row of boards along the perimeter of the walls and fasten them using anchor screws with a countersunk head and a metal sleeve. For drilling holes in concrete or brickwork We use a hammer drill, having previously drilled the board with a drill with a regular drill bit.
• We lay the second row of boards on top of the first row so that the joints of the boards do not coincide, and in the corners we lay the boards “in a bandage”
• We connect the rows together using 100 mm nails.

This fastening of the Mauerlat greatly facilitates lifting the material to a height - after all, the board is much lighter than timber.

And the strength of the resulting structure is quite sufficient, especially if a relatively light roof of a frame house is being erected.

Installation of rafters

The next stage in the construction of the roof frame is the installation of rafters. To make the work easier (especially if you work alone), all processing of the rafter beams is done on the ground.

This makes it more convenient to cut the beams to size, give them the desired shape using a template, cut out the necessary grooves and drill mounting holes. Only after this do we lift the rafter parts up and begin fastening them.

The technology for manufacturing a roof frame with a hanging rafter system is as follows:

• We make grooves in the mauerlat for installing rafter legs. The distance between the rafter legs is determined at the stage of choosing the type of rafter system, but in any case should not exceed 1.5 m - otherwise the structure will have clearly insufficient rigidity.

Note! If you plan to insulate the roof, then it is advisable to coordinate the distance between the rafters with the dimensions insulation material. By laying solid sheets or pairs of insulation sheets in the space between the rafters, you will significantly save time on trimming.

• We begin the installation of rafters with the gables - the end parts of the roof. Having installed the rafters at the ends, we stretch a cord between their ridges, and use it to guide us when aligning the intermediate rafters vertically.
• We insert the rafter legs into the grooves. To fix the rafter leg in the mauerlat, we use complex fasteners: the transverse displacement of the rafter is limited by a steel bracket, and the longitudinal displacement is limited by the bracket with which the rafter is attached to the mauerlat.
• When installing rafters, you need to remember that the rafters must protrude beyond the perimeter of the building. The optimal size of this protrusion (it is called an overhang or overhang of rafters) is 40 cm - this is how the walls of the building are protected from water flowing down the roof. In addition to the protrusion of the rafter beam itself, the overhang can be equipped by extending the rafters with an additional thinner board - the so-called “filly”. The “filly” is attached to the rafters using nails through a spacer - a short piece of board.

• We fix the lower parts of the rafters with strapping, which is used as a base for the attic floor. The strapping bars rest on the mauerlat.
• If it is necessary to extend the rafter beams (if their length is insufficient), we lay two beams on an overlay with an overlap of at least a meter. To fix the beams we use pins with a diameter of 8 to 12 mm.
• We connect the rafters to each other using pins, which we insert into the drilled holes. To prevent rotation of the rafters around the axis of the stud, each pair of rafters must be secured with two studs.
• If the roof width is within 6 m, then we connect the hanging rafters with an additional cross beam - a tie - in the shape of the letter “A”. We make the puffs from boards 50x100 or 50x150 mm, and fasten them to the rafters with self-tapping screws. It is also possible to install a tie made of 3 x 30x100 mm boards located on both sides of the rafters.
• In the upper part, we fix the trusses using a longitudinal ridge beam or ridge board.

• To enhance the upper rafter assembly You can connect the ridge beam to the tie with an additional piece of board. This is done to avoid deflection of the tie when there is a large distance between the rafters.

We repeat the above operations for all rafter pairs. After all the rafters are installed, you can begin arranging the sheathing.

Lathing

There are two types of roof sheathing: solid and thinned. The choice of sheathing type is determined by the type of roofing material.

To construct a continuous sheathing, OSB boards or moisture-resistant plywood of sufficient thickness (10 mm or more) are used, the sheets of which are stuffed onto the rafters through a counter-batten. Continuous sheathing is suitable for laying soft and rolled roofing materials.

When constructing thinned sheathing, beams or boards are placed on them, the distance between which depends on the dimensions of the roofing material used.

If austerity is necessary, for this type of lathing, you can use an unedged board instead of timber.

The thinned sheathing is placed on the rafters from top to bottom. To increase the strength of the structure, we fill the first rows of the sheathing, starting from the ridge beam, without a gap.

After the sheathing is completed, you can begin work on roof insulation, laying waterproofing and roofing work.

Despite the complexity of the process, it is quite possible to build a roof frame with your own hands. And if you take up the work “fully armed”, then you will invariably be successful.

Rafters and sheathing - the roof frame that bears all the weight roofing pie, thermal insulation, snow load, so they must have high load-bearing capacity and strength. The idea of ​​using metal rafters to make the roof structure more rigid is not new, but previously it was used mainly for covering industrial or utility structures. Now the rafter frame and metal profile sheathing are considered real alternative wooden roof elements if the length of the slope exceeds 10 meters.

The roof truss frame structure consists of many interconnected elements that form trusses. The pitch, the cross-sectional size between the rafters and other supports is determined by the calculation of the loads to which they are subjected during operation. The roof frame performs the following functions:

1. Load distribution. Interconnected nodes, reinforced with corners, evenly distribute the weight of the roof, which can reach up to 500-600 kg, taking into account the snow load. The larger the cross-section of the rafters and the smaller the pitch between them, the greater the load-bearing capacity of the structure.
2. Giving slope and shape. The rafters, located at an angle to the base of the roof, form an inclined plane of the slopes, so that snow and water do not accumulate on the roof surface.
3. Forming a base for fixing the roofing material. The finishing coating of the roofing pie is attached to the roof frame. The sheathing acts as a basis for fixing the covering, distributing its weight evenly across the rafters.

Note! What should all the nodes, rafters and sheathing be like? roofing structure determines the engineering calculation. To determine the required load-bearing capacity of the frame, it is necessary to calculate the total load to which it will be subjected. To do this, add the weight of the roofing material, insulation, waterproofing, maximum snow load with the weight of the rafter system.

Types of rafter systems

The most common material from which the sheathing and rafters of the roof frame are made is wood. However, if the weight of the roofing material is large enough and the length of the slope is more than 6 meters, then the structure turns out to be too massive. Builders have to reduce the pitch between the rafter legs and increase their cross-section, which is why the roof assemblies acquire a lot of weight, increasing the load on the foundation. You can relieve load-bearing walls and the base of the building by using stronger, but lighter metal rafters. According to the type of material used, they are distinguished following types rafter systems:

• Wooden. Rafters and lathing made of wood are used for the construction of roofs, the length of the slope of which does not exceed 7-10 meters. The frame elements are fastened to each other using self-tapping screws, nails or movable metal elements. The step between the legs is usually within 50-80 cm.
• Metal. Metal roofing frames are made from steel metal profiles with a zinc coating, which is not afraid of moisture. Rafters and sheathing made of this material are light and durable, so the step between them can be increased to 1.5-2 meters. The metal profile is fastened using welding or fasteners. Metal roof components are used for slope lengths of 10 meters or more.
• Combined. Rafter frame combining metal and wooden knots, called combined. The combination of support elements made of wood and galvanized steel allows you to create a cheaper structure with high load-bearing capacity, increasing the pitch between the rafters.

Please note that metal and wooden frame elements cannot be connected to each other without a gasket made of waterproofing material or treatment with an antiseptic drug. Since metal has high thermal conductivity, its proximity to wood leads to the formation of condensation and rotting of the rafters.

Fastening methods

Metal rafters are assembled into triangular, trapezoidal or arched trusses. Internal stiffeners are attached to the frame beams, which form corners that significantly increase the load-bearing capacity of the frame. This system allows you to make the pitch between the rafters larger, taking into account the support capabilities of each truss. Fastening the metal elements of the roof frame is performed using one of the following methods:

1. Fastening by welding. If you weld the parts of the rafter system using welding machine, it is possible to obtain a rigid structure with high strength and load-bearing capacity. If you correctly calculate the roof, you can lighten the frame and reduce the load on the foundation of the structure. The disadvantage of this method is that only a professional can perform welding using special equipment.
2. Fastening with bolts. Fixing the rafters with fasteners allows you to perform less rigid mount. This method of assembling a rafter frame based on a metal profile is used in private housing construction, where the length of the slopes does not exceed 10 meters. Eliminating welding allows for faster roof installation.

Experienced craftsmen rely on the fact that the rafters can withstand more weight than wooden ones, so you can increase the step between them and reduce the thickness of the cross-section of the elements. Moreover, construction stores sell ready-made trusses, fastened by welding, suitable for covering buildings of standard width.

Advantages

Metal rafter frames are used for the construction of roofs of any shape, any slope with a slope of 1-2 degrees. The materials from which rafters and sheathing are made are steel angles, round and rectangular pipes, and brands. In order to correctly select the thickness of the frame elements and choose the pitch between them, a calculation of the roof structure is performed, taking into account the permanent and temporary loads that are transferred to the rafter beams during operation. The advantages of a rafter system made from this material are:

• Fire safety. Unlike wooden ones, metal beams the frame is not in a fire zone, which increases the fire safety of the building.
• Easy to maintain. Zinc electroplating, which covers steel corners, protects the roof frame from corrosion throughout its entire service life. They, unlike wooden ones, do not require annual treatment with an antiseptic.
• Zero waste. Although metal constructions are quite expensive, it is considered cost-effective, since fastening is carried out by welding, and there is practically no waste left.
• Long service life. If you correctly calculate the loads, then roof frame made of metal will last more than 100 years, which exceeds the service life of even the most durable roofing coverings.

Professional roofers believe that it is advisable to use welded metal structures for the manufacture of roof rafter frames with a slope length of 10-12 meters. In this case, the main task is to correctly calculate the loads, and then determine the step between the legs in accordance with the climatic characteristics and properties of the roofing material.

Flaws

Despite the obvious advantages, metal rafter systems are not the most popular constructive solution in private housing construction. Even a large step between the rafters and sparse lathing with the high cost of metal cannot make the structure cheaper than a wooden one. Disadvantages metal rafters consider:

1. High thermal conductivity. Metal has high coefficient thermal conductivity, which is why the rafters form cold bridges. From the point of view of energy efficiency, a frame made of metal profiles is not the best solution.
2. Problematic transportation and installation. When choosing a metal rafter system, take into account that transporting, lifting and fastening long and heavy elements is more difficult than standard-length lumber rafters.
3. Difficult to install. To lift the trusses to a height and fix them, special equipment is used, the rental or purchase of which is expensive.
4. Deformation under high temperature. Although metal is considered non-flammable materials, during a fire it is severely deformed, which usually leads to the collapse of the roof.

To determine whether it makes sense to use more expensive rafter elements made of metal profiles, you need to calculate the roof frame. If the length of the slope exceeds 10 meters and the load is more than 450-600 kg, then installation metal frame economically feasible.

Video instruction

Roof construction is one of the the most important stages construction of a house. Rafter part roof required special attention, both at the design stage and at the stage of direct assembly. Before you begin installing the roof truss system, you will have to understand all the intricacies of the issue. Calculations are best left to professionals. Roof design takes into account great amount factors are wind and snow loads, weight of the rafter system and roofing materials, geometry and technical specifications buildings.

There are specialized computer programs to calculate optimal design roofs and counting the amount needed building materials. Loads and impacts can be clarified in the SNiP 2.01.07-85 of the same name. Correction factors for individual regions are also given there. Almost all calculations must be increased by 10% to create a safety margin.

After the roof project is ready, the question arises about the correct installation of the roof rafters. Rafter trusses, in most cases, are a triangle. This is the most durable and cost-effective form. Rafters can be made from various materials: wood, metal or reinforced concrete.

A combination of different materials in one design is also allowed.

Rafter connections

Rafter trusses can be made independently, in accordance with the project, or ordered factory-made. Manufacturing to order does not impose restrictions on shape, volume and size. At the factory, both the entire rafter system and individual elements can be made for subsequent assembly directly on site. Rafter fastenings industrial production usually performed using metal plates provided by the manufacturer. Rafters made independently are connected using a tongue-and-groove pattern and reinforced with nails, bolts, staples and clamps.

It must be taken into account that the wooden elements of the rafter system should have a humidity of no higher than 20%. The material may shrink. Fastening roof rafters with nails or staples is only permissible for dry material. If the humidity percentage raises even the slightest doubt, you should choose bolting. They can be tightened over time, but the bolt holes weaken the strength of the rafters.

Design requirements

There are three main requirements for the design of the roof truss:

• Rigidity;
• Optimal weight;
• Quality of materials.

The requirement of rigidity directly relates to the joints and fastenings of all elements of the rafter system. As mentioned above, the rafter system is a system of triangular trusses installed parallel to each other. The triangular shape itself ensures the rigidity of the structure, but the rafters must be securely fastened relative to each other. Even the slightest movement can lead to disastrous consequences.

The requirement for optimal weight is fulfilled at the calculation stages. Total weight consists of all elements of the rafter system, hydro-steam and thermal insulation, and roofing material. Eg, natural tiles weighs 40-60 kg/m2, slate 10-14 kg/m2, bitumen tiles 6-8 kg/m2, and metal tiles 3.5-4.5 kg/m2. It is necessary to take into account how much weight the supporting walls of the building can withstand, with taking into account constant and variable loads, because the influence of wind and the volume of snow will be added to the mass of the roof itself.

The quality of materials can be assessed according to several parameters. The type of wood should be 1-3 grades, with minimum quantity knots. Preference is given to coniferous species. The permissible board length for softwood is 6.5 m, for hardwood – 4.5. Mauerlat, pillows and purlins are made from hard hardwood.

Regardless of the cost and quality of materials, it is necessary to remember about waterproofing and processing of all wooden elements antiseptics and fire retardants.

Main parts of the rafter system design

Mauerlat- This is the base of the rafter system. Mauerlat evenly distributes the load on the external walls of the building.

Rafter leg– rigidly fixes the roof elements, is responsible for the angle of inclination of the slope. It depends on the location of the rafter legs appearance roofs.

Run– fastens the rafter legs. The ridge purlin is located at the top, the side purlins are located on the side.

Puff– fastens the rafter legs at the bottom and prevents them from moving apart. Racks and struts provide additional rigidity to the rafter system.

Sill– located below, parallel to the ridge and serves as the base and support for the posts and struts.

Lathing– arranged perpendicular to the rafter legs. Made from boards or bars. It is designed to transfer the load from the roofing material to the rafters and serve as the basis for the roofing material.

Part names

Roof ridge– the junction of two roof slopes. A continuous sheathing is placed along the ridge to strengthen this part of the structure.

fillies– arranged to organize an overhang.

Eaves- this is the distance from the wall of the house to the edge of the roof, intended to protect the house from excess rainfall on the walls.

Shapes of roofs and rafter systems

The shape of the roof is determined primarily by the geometry of the building. Various shapes roofs can be combined in cases of complex structures.

Roof shapes

Roofs with a slope of 2.5 to 10 degrees are called flat. Not every building can be covered flat roof. The dimensions of the structure and variable loads characteristic of the construction region are important.

A pitched roof has the simplest rafter system design and a slope of 14 to 26 degrees. This roofing arrangement is ideal for extensions, verandas, and small structures in which one of the parallel walls is higher than the other.

Shed roof

A roof with two slopes has a more complex rafter system. The under-roof space can be either non-residential, attic, or attic, landscaped. Slope gable roof accepted in the range from 14 to 60 degrees. Gable roof rafter systems also differ in type. They can be hanging or layered, depending on the dimensions and geometry of the building.

Types of rafter systems

A hip roof is called a hip or half-hip roof. The slope of such a roof is allowed from 20 to 60 degrees, and the length of the covered span can be up to 12 meters. This design requires internal supports. The absence of gables significantly saves materials, but the design and installation of the rafter system requires more attention and means than in the case of a gable roof.

Sloping roofs in the lower tier can have a slope of up to 60 degrees, while the upper tier is usually flatter. Most often, a sloping roof is used to construct an attic. The permissible width of the house is up to 10 m.

This type of roof is called a sloping roof

Rafter systems can also vary in shape.

Various rafter systems

The shape of the rafter system is determined by the dimensions of the structure and the purpose of the under-roof space. Struts, racks and the rafters themselves can be used as decorative elements interior or attic.

Decorative elements

Types of rafter systems

Among other things, rafter systems also differ in type. They come hanging and layered. The choice of the type of rafter systems depends, like everything else in the roof, on the dimensions of the structure to be covered and the position of the load-bearing walls.

Hanging rafter system

Hanging rafters

System with hanging rafters chosen if the building has no internal load-bearing walls and the span does not exceed 6 meters. At the top, the rafters rest on each other, and at the bottom, the mauerlat acts as a support. Mauerlat is installed in stone or brick house. In the case when the house is built according to frame technology, the rafters are attached to top harness. In log houses made of logs or timber - to the upper crown. The rafter expansion is reduced by tightening. Beam ties can serve as a ceiling for the upper floor.

The tightening is located at the very bottom. If it is placed higher, it is called a crossbar. In cases where the overlapped span is more than 6 meters, a system with hanging rafters is complemented support posts and braces. To organize the overhang, fillies are used. Experts recommend extending the rafters with a mare, even if it is possible to organize an overhang due to the rafter’s own length. Such an extension will allow the rafters to be supported on the Mauerlat with the entire available cross-sectional area. And the cross-section of the filly is chosen smaller than the cross-section of the rafters.

Layered rafter systems

Layered rafters

The main requirement for organizing a layered rafter system is the presence in the building of an internal load-bearing wall or columns. A roof with layered rafters can cover spans from 10 to 16 meters. The slope is selected based on the weather conditions of the area. In the upper part, the rafters rest on the ridge girder, in the lower part - on the mauerlat. Parallel ridge run a bench is arranged on which the racks rest. This allows you to do without puffs and crossbars. If the rafter leg does not have a strut or support, its length should not exceed 4.5 meters. Elements of the layered rafter system must have a thickness of at least 5 cm.

Regardless of what type of rafter system was designed, it is important:

• You cannot add nodes to the roof project on your own. Even if it seems that it would be more reliable. Shifting loads, even the slightest at first glance, can lead to distortion of the structure and possible collapse.
• The Mauerlat must be leveled in a horizontal plane relative to the walls of the house. Next, just as strictly horizontally, they connect it to the rafter leg. Vertical and horizontal levels are extremely important in order to prevent distortions.
• Rafter legs, racks and struts are placed strictly symmetrically.
• To prevent the rafters from rotting, ventilation is provided in the attics, and cracks in the attics.
• It is important to comply with the technology of insulation and vapor barrier of the roof.
• Places of joints of wooden elements with stone walls must be lined with waterproofing materials.
• When calculating the rafter system, it is important to take into account the location of the chimneys. This may affect the spacing of the rafters.

Connecting elements

A system of fastening elements using the cutting method is allowed, but it should be remembered that this is not the most economical way. Cutting requires quite large area sections, so that the structure as a whole does not lose its strength. This means that both the weight of the entire roof and the cost of building materials will be significantly higher. In this regard, most often the units are secured with dowels and bolts.

Fastening

Fastenings using perforated steel plates are often used. There are a huge number of such fasteners on sale, varying in shape and purpose. Perforated pads have a special coating that protects them from corrosion. They are secured with nails.

Rafter system

But it is unacceptable to relax at this step. Minor miscalculations will lead to the need for premature repairs, and if a serious mistake is made, the entire building may collapse. Find out which materials are suitable for the chosen project, consider the type of roof, decide whether the building needs an attic space and whether it will be used. Explore brief instructions for installation, to do everything yourself or supervise the work of the craftsmen.

Preparatory work

You can build the roof of a frame house with a flat roof with your own hands, but it is better not to take on more complex projects alone. Even at the stage of designing a house, it is important to think about:

• Roof shape.
• The slopes that will need to be made for the slopes.
• Roofing material.
• Device rafter system.
• The distance between the rafters and their cross-section.
• Sheathing step.
• Materials for insulation, vapor barrier, waterproofing.

Types of roofs by shape

The shape of the roof of a frame house is:

• Flat single-pitch is the cheapest and easiest to install.
• Gable - suitable for one-story and two-story houses with a small area and rectangular buildings.
• Broken line - ideal for projects with an attic.
• Four-slope - used for buildings of any type, resistant to wind loads.
• Multi-pincer – complex design, consisting of several slopes. Suitable for multi-level house projects.
• Spire-shaped - original, ideal for snowy regions, but requires complex calculations.

When choosing a roof shape, consider:

• Area, number of floors, general project and home design.
• Selected roofing material.
• Climatic conditions of the region (wind, snow).
• Budget.

It should be noted that the safest is considered slope slope ranging from 30 to 45 degrees.

Basic material selection criteria

For the roof of a frame house, you can choose various roofing materials, but preference should be given to lighter ones. This rule is especially important if the foundation is not designed for heavy loads.

• bitumen shingles;
• polymer sand tiles;
• corrugated sheeting;
• slate;
• metal tiles;
• cement-sand tiles.

For heavy roofing materials, lathing should be done more frequently. Additionally, you need to use a layer of waterproofing material. It is necessary to monitor the step of fastening the main roofing material. If you do it more often, the likelihood of roof leaks can be minimized.

When installing roofing materials, it is important to adhere to the following tilt angles:

• Minimum 10 degrees for corrugated sheets.
• From 12 and 60 degrees for slate.
• For Euro slate, the lower figure is 6 degrees.
• For ceramic tiles– from 18 to 60 degrees. The same indicator should be followed when fixing polymer sand tiles.
• For bitumen shingles - more than 12 degrees.
• Metal tiles require installation at an angle of over 15 degrees.

Features of roof installation

The easiest way is to do it yourself pitched roof, other options will require knowledge and experience.

Roof construction includes the following stages:

• Installation of the rafter system.
• Installation of material for insulation, vapor barrier and waterproofing.
• Lathing and counter-lattice.
• Installation of roofing material.

The rafter system of the roof of a frame house must be correctly calculated. To do this, the section, pitch and the length itself are analyzed. Builders note that, first of all, the strength of the structure depends on the following parameters:

The cross-section can be selected using special construction tables or you can perform all the calculations yourself.

Installation of the rafter system

The roof of a frame house will last a long time if it is fixed correctly and firmly ceiling beams. For this, it is recommended to use timber with a section of 50 by 150 (200) mm.

At the first stage, you will need to create a special template for the rafter legs. To do this, all manipulations should be performed according to the following scheme:

1. Take two boards and place them at right angles to each other. For strong fixation, ordinary nails can be used.
2. The resulting element is additionally secured to one edge of the Mauerlat.
3. By moving the boards, set the angle, which will later be used as a ramp.
4. From the edge of the wall retreat at least 40 centimeters. The resulting space will be used for water drainage.
5. After obtaining the required angle, securely fix the beam. Builders advise marking the cut line with a simple pencil.

After preparing several templates, you will need to connect two pairs of rafters together. Fastening is done on both sides. If necessary, legs can also be extended separately in the future.

Regular thick bolts are quite suitable for joining. This option is several times safer, especially when compared with fastening with nails. Between two adjacent legs you will additionally need to install a transverse fastening option.

Single-pitch frame house will be protected from bad weather if all roofing elements are installed correctly. To do this, a rope is pulled between the side rafters. It will serve as a beacon and guideline against which the level is checked. Further elements are secured at a distance of 60 or 80 centimeters. This step is recommended to be followed at all times.

The calculations necessary to determine the number of rafters are made in advance. Between individual elements roof truss you will need to nail two boards. They will provide the necessary fixation. For additional protection from precipitation, you should install diffuse membrane.

The size and pitch of the sheathing can be calculated independently using formulas. In this case, it is necessary to take into account the slope and characteristics of a particular material. For the construction of the sheathing, it is possible to choose a beam whose cross-section is from 40 to 50 mm.

Laying roofing material

At the first stage, the cornice strip is installed. For this it is advisable to use self-tapping screws. Only after this is it allowed to lift metal tiles onto the roof. It is also attached to cornice strip using self-tapping screws.

There are situations when one sheet is not enough. In this case, it is advisable to increase the length. To do this, the fastening is done with an overlap. All material is laid using this technology.

The video describes the installation of the roof in detail and in an accessible manner.