Classification of roofs: design, types, shapes, elements. Structural elements of the roof - what it consists of and what materials are made from Composite roof

Each roof is based on a large number of beams, rafters, posts and purlins, which are collectively called the rafter system. Over the centuries-old history, many types and methods of its organization have accumulated, and each has its own characteristics in the construction of nodes and cuts. Let's talk in more detail about what the rafter system of a gable roof can be and how the rafters and other elements of the system should be attached.

Design of a gable roof truss system

In cross-section, a gable roof is a triangle. It consists of two rectangular inclined planes. These two planes are connected at the highest point into a single system by a ridge beam (purlin).

Now about the components of the system and their purpose:

Mauerlat is a beam that connects the roof and walls of a building, serves as a support for rafter legs and other elements of the system.
Rafter legs - they form the inclined planes of the roof and provide support for the sheathing under the roofing material.
Ridge purlin (bead or ridge) - combines two roof planes.
Tightening is a transverse part that connects opposite rafter legs. Serves to increase structural rigidity and compensate for thrust loads.
Lezhny - bars located along the mauerlat. Redistribute the load from the roof.
Side purlins - support the rafter legs.
Racks - transfer the load from the purlins to the beams.

There may still be fillies in the system. These are boards that extend the rafter legs to form an overhang. The fact is that to protect the walls and foundation of the house from precipitation, it is desirable that the roof ends as far from the walls as possible. To do this, you can take long rafter legs. But the standard length of lumber of 6 meters is often not enough for this. Ordering non-standard is very expensive. Therefore, the rafters are simply extended, and the boards with which this is done are called “fillies”.

There are quite a few designs of rafter systems. First of all, they are divided into two groups - with layered and hanging rafters.

With hanging rafters

These are systems in which the rafter legs rest only on the external walls without intermediate supports (load-bearing walls). For gable roofs, the maximum span is 9 meters. When installing a vertical support and a strut system, it can be increased to 14 meters.

The good thing about the hanging type of gable roof rafter system is that in most cases there is no need to install a mauerlat, and this makes the installation of rafter legs easier: there is no need to make cuts, just bevel the boards. To connect the walls and rafters, a lining is used - a wide board, which is attached to studs, nails, bolts, crossbars. With this structure, most of the thrust loads are compensated, the impact on the walls is directed vertically downwards.

Types of rafter systems with hanging rafters for different spans between load-bearing walls

Gable roof rafter system for small houses

There is a cheap version of the rafter system when it is a triangle (photo below). Such a structure is possible if the distance between the external walls is no more than 6 meters. For such a rafter system, you can not calculate the angle of inclination: the ridge must be raised above the tie to a height of at least 1/6 of the span length.

But with this construction, the rafters experience significant bending loads. To compensate for them, either rafters of a larger cross-section are taken or the ridge part is cut in such a way as to partially neutralize them. To give greater rigidity, wooden or metal plates are nailed on both sides at the top, which securely fasten the top of the triangle (also see the picture).

The photo also shows how to extend rafter legs to create a roof overhang. A notch is made, which should extend beyond the line drawn from the inner wall upward. This is necessary to shift the location of the cut and reduce the likelihood of the rafter breaking.

Ridge knot and fastening of rafter legs to the backing board with a simple version of the system

For mansard roofs

Option with installing a crossbar - used when. In this case, it serves as the basis for lining the ceiling of the room below. For reliable operation of a system of this type, the crossbar cut must be hingeless (rigid). The best option is in a semi-frying pan (see picture below). Otherwise, the roof will become unstable to loads.

Please note that in this scheme there is a Mauerlat, and the rafter legs must extend beyond the walls to increase the stability of the structure. To secure them and dock them with the Mauerlat, a notch is made in the form of a triangle. In this case, with an uneven load on the slopes, the roof will be more stable.

With this scheme, almost the entire load falls on the rafters, so they need to be taken with a larger cross-section. Sometimes the raised puff is reinforced with a pendant. This is necessary to prevent it from sagging if it serves as a support for ceiling cladding materials. If the tie is short, it can be secured in the center on both sides with boards nailed to the nails. With a significant load and length, there may be several such belays. In this case, too, boards and nails are enough.

For large houses

If there is a significant distance between the two outer walls, a headstock and struts are installed. This design has high rigidity, since the loads are compensated.

With such a long span (up to 14 meters), it is difficult and expensive to make the tie in one piece, so it is made from two beams. It is connected by a straight or oblique cut (picture below).

For reliable joining, the connection point is reinforced with a steel plate mounted on bolts. Its dimensions must be larger than the dimensions of the notch - the outer bolts are screwed into solid wood at a distance of at least 5 cm from the edge of the notch.

In order for the circuit to work properly, it is necessary to make the struts correctly. They transfer and distribute part of the load from the rafter legs to the tie and provide structural rigidity. Metal pads are used to strengthen connections

When assembling a gable roof with hanging rafters, the cross-section of lumber is always larger than in systems with layered rafters: there are fewer load transfer points, therefore each element bears a greater load.

With layered rafters

In gable roofs with layered rafters, the ends rest on the walls, and the middle part rests on load-bearing walls or columns. Some schemes push through the walls, some don't. In any case, the presence of a Mauerlat is mandatory.

Non-thrust schemes and notch units

Houses made of logs or timber do not respond well to thrust loads. For them they are critical: the wall may fall apart. For wooden houses The rafter system of a gable roof must be non-thrust. Let's talk about the types of such systems in more detail.

The simplest non-thrust rafter system diagram is shown in the photo below. In it, the rafter leg rests on the mauerlat. In this version, it bends without pushing the wall.

Pay attention to the options for attaching the rafter legs to the Mauerlat. In the first, the support area is usually beveled, its length being no more than the section of the beam. The depth of the cut is no more than 0.25 of its height.

The top of the rafter legs is laid on the ridge beam, without fastening it to the opposite rafter. The structure results in two pitched roofs, which in the upper part are adjacent (but not connected) to one another.

The option with rafter legs fastened at the ridge part is much easier to assemble. They almost never push against the walls.

To operate this scheme, the rafter legs at the bottom are attached using a movable connection. To secure the rafter leg to the mauerlat, one nail is driven from above or a flexible steel plate is placed from below. See the photo for options for attaching rafter legs to the ridge girder.

If you plan to use heavy roofing material, it is necessary to increase the load-bearing capacity. This is achieved by increasing the cross-section of the rafter system elements and strengthening the ridge assembly. It is shown in the photo below.

Reinforcing the ridge assembly for heavy roofing material or for significant snow loads

All of the above gable roof schemes are stable in the presence of uniform loads. But in practice this practically never happens. There are two ways to prevent the roof from sliding towards a higher load: by installing a screed at a height of about 2 meters or by struts.

Options for rafter systems with contractions

Installing contractions increases the reliability of the structure. In order for it to work properly, it needs to be secured to them with nails at the places where it intersects with the drains. The cross-section of the timber for the scrum is the same as for the rafters.

They are attached to the rafter legs with bots or nails. Can be installed on one or both sides. See the figure below for attaching the screed to the rafters and ridge girder.

In order for the system to be rigid and not “creep” even under emergency loads, it is enough to ensure rigid mount ridge beam. In the absence of the possibility of its horizontal displacement, the roof will withstand even significant loads.

Layered rafter systems with struts

In these options, for greater rigidity, rafter legs, also called struts, are added. They are installed at an angle of 45° relative to the horizon. Their installation allows you to increase the span length (up to 14 meters) or reduce the cross-section of beams (rafters).

The brace is simply placed at the required angle to the beams and nailed on the sides and bottom. An important requirement: the strut must be cut accurately and fit tightly to the posts and rafter leg, eliminating the possibility of it bending.

Systems with rafter legs. The top is a spacer system, the bottom is a non-spacer system. The correct cutting nodes for each are located nearby. Below are possible strut mounting schemes

But not in all houses the average load-bearing wall is located in the middle. In this case, it is possible to install struts with an angle of inclination relative to the horizon of 45-53°.

Systems with struts are necessary if significant uneven shrinkage of the foundation or walls is possible. Walls can settle differently on wooden houses, and foundations can settle on layered or heaving soils. In all these cases, consider installing rafter systems of this type.

System for houses with two internal load-bearing walls

If the house has two load-bearing walls, install two rafter beams, which are located above each of the walls. The beams are laid on the intermediate load-bearing walls, the load from the rafter beams is transferred to the beams through the racks.

In these systems ridge run they don’t install it: it provides spacer forces. The rafters in the upper part are connected to one another (cut and joined without gaps), the joints are reinforced with steel or wooden plates, which are nailed.

In the upper non-thrust system, the pushing force is neutralized by the tightening. Please note that the tightening is placed under the purlin. Then it works effectively (top diagram in the figure). Stability can be provided by racks, or joints - beams installed diagonally. In the spacer system (in the picture it is below) the crossbar is a crossbar. It is installed above the purlin.

There is a version of the system with racks, but without rafter beams. Then a stand is nailed to each rafter leg, the other end of which rests on the intermediate load-bearing wall.

Fastening the rack and tightening in the rafter system without a rafter purlin

To fasten the racks, 150 mm long nails and 12 mm bolts are used. Dimensions and distances in the figure are indicated in millimeters.

The roof occupies a priority place in the functional purpose of the building. It’s not for nothing that people say: “if only there was a roof over your head.” After all, without it, even the strongest walls will not last long - they will be destroyed by water, wind and sun. What structural elements the roof consists of, what role the roof plays in its composition and how to properly maintain this structure will be discussed below.

What is a roof and what does it consist of?

The words roof and roofing are often used interchangeably. Meanwhile, in strict terminology, these are different, although interrelated concepts.

The roof is the structure crowning the structure, which serves as protection from adverse atmospheric influences. The main purpose of the roof is to protect the building from precipitation: rain, snow, melt water. In addition, it performs heat-insulating functions, preventing the leakage of warm air from the room and overheating of the internal space under the influence of solar radiation.

The roof is an integral part of the roof and is an external waterproofing coating that prevents moisture from penetrating inside. The main purpose of the roof is to drain water from the roof surface. In order for water to flow in the desired direction, the roof is located at an angle to the horizontal axis. Even flat roofs have a certain angle of inclination (up to 12 o), due to which atmospheric moisture enters the drainage gutters.

The roof is the outer part of the roof that is in direct contact with the atmosphere

Roofing device

Structurally, the roof is divided into several elements.

Bearing layer. Consists of sheathing, screed or solid flooring. The type of support lining is determined by the type of roof covering and roof installation technology.
For light sheet coverings on pitched roofs, the base is usually a sparse sheathing made of wooden slats or metal profile
Insulation layer. There are:
Roofing covering. The topmost layer that is in direct contact with the external environment. The main characteristics of the coating are durability, strength and weight.

Different designs can combine one or more layers of insulating materials.

When choosing roofing coverings, the following properties are taken into account:

resistance to solar radiation;
waterproof;
elasticity;
resistance to temperature changes.

Types of roofing

There are many materials from which roofing coverings are made. They can be divided into two large groups. One category includes roofs made from natural components - metal, stone, sand, asbestos, as well as straw, reeds, reeds and even moss. Another group, which arose not so long ago, includes polymer and synthetic types of roofing - bitumen, ceramic tiles, roofing felt, etc. The raw materials for production are petroleum products combined with paper, fiberglass, ceramic chips and other components. Recently, polymer additives that are added to the composition have become widespread roofing material. Plasticizers prevent cracking and corrosion of the outer covering and significantly increase the service life of the roof.

Below is a list of the most commonly used roofing materials.

Slate. A group of roofing coverings made of cement and asbestos, which have undergone molding and heat treatment under pressure, is in great demand, their production is growing every year. This is due to the low price and high quality products.
Slate is one of the most popular roofing materials
Ruberoid. Roofing roll material with high waterproofing properties. It is made by impregnating construction cardboard with bitumen, followed by coating with a refractory compound and anti-stick coating (sand, talc or asbestos).
Roofing felt is usually laid in several layers, changing direction so that the last row is vertical
Profiled sheeting. Profiled steel sheet treated with zinc, polymer powder paint or other water-repellent composition.
To cover the roof, you can use only special roofing types of corrugated sheeting, which are characterized by increased load-bearing capacity and high wave height
Roofing made of zinc-titanium alloy (or D-zinc). It looks like tinned copper and has a service life of up to 140 years. Modern metallurgical technologies have reached a level where an alloy of titanium and zinc is cheaper for the manufacturer than pure copper roofing. Therefore, D-zinc has good prospects as a roofing coating.
Wavy bitumen sheets(ondulin). They consist of construction cardboard 1.5–3 mm thick, impregnated with a light fraction of bitumen.
In appearance, ondulin is very similar to slate, but the composition of these roofing materials is very different
. Another name is slate shingles. It is made from certain rocks by splitting into flat plates. It has an almost unlimited service life.
Slate tolerates weather anomalies well and is slightly sensitive to mechanical damage
. The starting material is wood. The dried blanks are used to cover the roof in the manner of tiles.
Wooden shingles are an environmentally friendly coating that lasts 50 years or more
Sheet steel coated with zinc. Used in standing seam roofing. The connection of sheets and plates (rebates) is made by folding the edges into a single surface.
Steel sheets are connected using a seam lock, which ensures high tightness of the connection
Roofing made of copper sheets. One of traditional types coverings in the Middle Ages to the present day. It is resistant to mechanical damage and adverse atmospheric factors. A layer of copper oxide forms on the surface, which prevents corrosion. Layer thickness - from 0.5 to 1 mm.
Copper roofing is one of the most durable roofing coverings, lasting up to 150 years
Aluminum roofing material. A very promising type of coating. Unlike copper, which has a high cost and considerable weight, aluminum does not increase the load on the building structure. Minimum service life of 100 years. Coating with special polymer dyes provides the desired color scheme and durability of the roof.
Installation of aluminum sheets is carried out according to the principle of seam roofing
Tol. A product of impregnation of construction cardboard with tar made from coal or shale. The surface is sprinkled with mineral powders that protect the rolls from sticking.
Roofing felt has a short service life, so it is usually used to cover the roofs of outbuildings
Glassine. Applicable as auxiliary material for the installation of lining layers and is cardboard impregnated with a soft fraction of bitumen.
Ceramic plastic roofing. It is made from clay mixed with polyaffins (synthetic plasticizers), which are characterized by high reinforcing properties. During the production process, a permanent dye is added to the composition.
The shape of the ceramic plastic roof imitates slate shingles
Roof tiles. One of the most archaic building materials, known since Ancient Rome. Originally made from baked clay. Differs in a variety of forms and durability. This material has a large number of modern modifications:
- ceramic tiles are the closest analogue of ancient roofing material. Despite the large mass and labor-intensive installation, it is popular because it is a natural product;
  Ceramic tiles are assembled using sheathing laid in increments equal to the size of the tiles
- metal tiles - imitation ceramic coating, made of sheet steel by stamping. It has the advantage of being lightweight, but inferior in terms of thermal conductivity and noise absorption. Requires mandatory grounding;
  A generally recognized disadvantage of metal tiles is high sound conductivity
- bitumen tiles. Other names - soft or flexible tiles. It is produced by applying a layer of petroleum bitumen to fiberglass canvas. Due to its ease of manufacture, it comes in a variety of colors, shapes and sizes. Ease of assembly, good dielectric characteristics and sound insulation characteristics - all this contributes to the growth of popularity among consumers;
  Using soft tiles you can create complex patterns on the roof surface
- . A copy of a ceramic tile made from cement and sand. Its properties are comparable to the original, but it costs much less;
  The relatively low price contributes to the popularity of sand and cement tiles
- . Consists of sand bound with a polymer composition dye. Durable, flexible material, not subject to cracking under temperature and mechanical loads;
  The distinctive features of polymer-sand tiles are strength and lightness
- composite tiles. Piece products that are made from steel sheet coated on both sides with an anti-corrosion alloy. The outer layer is sprinkled with small stone granules and covered with a matte glass-like glaze. Despite its low weight, it has a very impressive appearance and a long service life.
  Composite tiles are available in a wide variety of colors; you can choose the desired shade from a special catalog
Straw, reed, turf. The material for knitting roofing mats is natural plant components, harvested in natural conditions. Despite the simplicity and availability of raw materials, development in industrial scale these technologies were not received. To this day, like thousands of years ago, harvesting is painstaking manual labor. The exception is turf, which is grown on specialized farms in pre-spread canvases. After reaching a layer thickness of more than 3 cm, the mats are rolled up and transported to the installation site. The disadvantage of reed, reed and thatch roofing is their flammability. With the arrival of electricity in every home, the risk of fire from a minor short circuit in the network has pushed aside traditional methods to the background. Safer materials have replaced them.
A thatched roof has very high thermal insulation properties, but requires painstaking manual labor and is highly flammable
Liquid types of roofing. These include solutions that harden in open air. Most often, such materials are used in industrial construction, since spraying them onto the surface of slopes requires serious equipment. An example is polyurea, which forms a waterproof layer within 10–15 minutes of application to the substrate. In private construction they are better known different kinds mastic, mainly bitumen-based. They are rarely used as an independent coating; mastic more often serves as an auxiliary agent for roof repairs.
Spraying polyurea requires special equipment and certain operator qualifications
Polycarbonate roofing. Appeared in the arsenal of roofers not so long ago. Polycarbonate is transparent and is not affected by ultraviolet rays. It is used for greenhouses, greenhouses, winter gardens and indoor swimming pools. You can often find polycarbonate roofs at bus stops in large cities. Popular visors over entrance doors from this material.
Polycarbonate is usually used to cover greenhouses, gazebos and canopies over building entrances

Roof installation

Depending on the installation technology, roofing materials are divided into:

typesetting (all types of tiles);
sheet (slate, metal sheet materials);
(roofing felt, roofing felt);
mastic (“liquid rubber”, polyurea);
membrane ( polyethylene films and membranes).

To avoid confusion and misconceptions, the consumer needs to remember that profiled metal materials, such as copper, corrugated sheets, aluminum, etc., are produced not only in the form of sheets, but also in the form of rolls. Flexible roofing also has different packaging - piece, roll, large membrane-type sheets and mastic. The choice of size and shape depends on the transportation conditions and type of installation.

Laying a piece roof is a more labor-intensive process. Nevertheless, this material is preferred for construction in the private sector. Large-sized membrane panels are used exclusively for the construction of large objects with large roof areas. This is explained by the fact that during installation the piece material is less prone to deformation and does not create longitudinal stresses along the sheathing.

Stacked laying of tiles is labor-intensive, but the result is a beautiful coating with a minimum amount of waste, which does not exert longitudinal loads on the sheathing

The support on which the roof is installed is the rafter system for pitched roofs, and the ceiling (or attic) floors for flat roofs. Before installing the outer covering on the roof, a sheathing is assembled, which can be sparse or solid.

Depending on the type of roofing material used, solid or sparse lathing is used to secure it.

The thickness of the sheathing depends mainly on the type and weight of the roofing:

To lay roofing felt, it is enough to lay a sheathing of boards up to 20–25 mm thick. At the same time, slate sheets, which weigh from 23 to 35 kg, require boards with a transverse size of 32 mm. The overlap between rolls of roofing felt should be 10–15 cm, between sheets of slate - one wave;
Installation of ceramic tiles is carried out on a sheathing made of timber with a thickness of 40 mm. In this case, first the top row at the ridge is completely laid out, then the row along the cornice, and after that the remaining rows are installed from the bottom up. The covering elements are attached to the sheathing with nails, and to each other using special grooves along the edges of each shingle;
soft tiles require a continuous covering underneath, but the thickness is not of great importance, since the total mass of the petals is small. Therefore, sometimes moisture-resistant plywood from 8 mm in diameter is sufficient. The bitumen sheets must overlap each other so that the upper element covers the place where the lower element is attached to the sheathing (this is done with galvanized nails with a wide head);
polycarbonate is mounted on a wooden or metal carcass in increments of 40–60 cm depending on the roof structure. Since the material is predominantly produced in large sheets (6 m x 2.1 m) and has exceptional flexibility, it is used to create extraordinary architectural forms. Fastening to the frame is done using self-tapping screws with large flat heads;
Seam roofing is assembled from panels by rolling the edges of adjacent sheets. To do this, each of them has sides that are bent using a special tool. The lathing is a metal or wooden frame. Due to the high thermal conductivity of the material, the composition roofing pie Insulation and vapor barrier must be included, which prevents the formation of condensation on the inner surface.

When installing a seam roof, a special tool is required to connect the sheets

The corrugated sheets are arranged with an overlap of at least 20–25 cm and a gradual horizontal displacement. The most critical roof elements, such as the ridge and valley, are additionally waterproofed with rolled or mastic material.

The lateral overlap of profiled steel sheets must be at least one wave

As can be seen from the examples given, the design of each type of roof has its own characteristics. However, the general principle remains. The roofing material is fixed to the roof using the sheathing, which serves as a connecting link between the rafter system and the roof.

The strength and durability of the entire structure depends on the quality of the lathing.

Video: DIY metal profile installation

Removal and replacement of the roof

When asked when a roof replacement is needed, the most convincing answer is a wet spot on the ceiling of the home. Especially when water drips from it with stubborn persistence.

It is not worth taking it to such extremes; it is better to regularly carry out an annual inspection of the roof and carry out preventive work in a timely manner. However, if the leak comes as an unfortunate surprise, you need to make a strategic decision. This requires an inspection of the roof and supporting structure.

Roof restoration work involves three possible solutions.

When the damage affected only the roof, cracks, chips, pockets of corrosion, violation of the tightness of joints, etc. formed on the roof surface; repairs are only needed for the roofing itself. The volume is determined by the area of the lesion. If 40% of the area or more is out of order, it is not advisable to patch such a roof. It is better and cheaper to replace the entire coating. For example, replace slate roofing with metal tiles.
Over time, cracks and through holes form on the slate, which require replacement of damaged sheets or the entire covering
If the wooden elements of the sheathing are damaged, fungus or mold is found on the surface of the boards or panels, blackening or salt protrusion, you will have to replace the sheathing frame along with the roof. Otherwise, the renewed roof will not last long, and the money will be wasted.
And the last, worst-case scenario - violations affected the rafter system, the geometry of the attic or attic room. The rafter legs have rotted, and the load-bearing or auxiliary structural elements (crossbars, tie-rods) have sagged. In this case, rafter repairs are necessary, which means complete dismantling of the roof cannot be avoided.
If, as a result of leaks, the load-bearing elements roof, it is necessary to completely dismantle the roofing pie and repair the rafter system

Dismantling is carried out in the reverse order of installation. For example, dismantling slate is carried out using a hammer and a nail puller. It is more convenient to disassemble such a roof with two people - one knocks the nails from the attic side, and the other pulls them out from outside. Next, the released sheet is lowered from a height to the ground and stored.

To remove the slate covering, you must remove all fasteners, and carefully lower the released sheets to the ground

When rebuilding the roof, for example, from slate to metal tile, it is necessary to adjust the shape of the sheathing, because slate is attached to one row, and metal tile to two. The second frame serves to strengthen natural ventilation under-roof space. If the covering is changed from soft tiles to corrugated sheets, there is no need to redo the sheathing. If it’s the other way around, you’ll have to cover the slopes with a continuous coating of OSB or plywood.

Under the bitumen shingles it is necessary to make a continuous sheathing on which the underlayment will be mounted

Dismantling must be carried out by a team or with an assistant. You cannot do this alone; safety precautions when performing high-altitude work prohibit being on the roof without a helmet and insurance.

If the roof was fastened with screws (corrugated sheeting, polycarbonate, etc.), then its disassembly is carried out using a screwdriver. The installer sequentially unscrews the fasteners and removes the sheets from the roof slopes.

Sheets of corrugated sheets connected to the sheathing with screws are unscrewed when dismantled with a screwdriver

Dismantling is considered the most labor-intensive flat roof, covered with several layers of roofing material (up to 5 or more). When heated in the sun, roofing material eventually bakes into a monolithic carpet, which is very difficult to remove. In this case, a roofing ax is used, with which the roofing is cut out into small islands and disposed of. On large areas, specialized organizations use curtain cutters - a mechanized tool that cuts the roof into pieces. There are wall cutters with electric or gasoline drive. They can only be used if the layer depth is at least 30 mm.

The wall cutter is designed for flat roofs with a thickness of 30 mm or more

Replacing a roof involves carrying out certain calculations. If the weight of the new coating exceeds the weight of the old (removed) one, it is necessary to correctly assess the ability of the rafter system to withstand increased loads. Sometimes it is necessary to strengthen the rafters by adding additional supporting elements. In this case, use old-fashioned methods Not recommended. It is advisable that the calculations be carried out by a competent engineer familiar with the specifics of the industry.

When replacing heavy types of roofing with lightweight ones, it is enough to calculate the weight of the roof per square meter. For example, when replacing slate with corrugated board, this can be done as follows.

It is known that a sheet of eight-wave slate weighs about 30 kg and has an area of 1.5 m2. Thus, per 1 m2 there are 30/1.5 = 20 kg.
The corrugated sheet has dimensions of 1.2x1.2 m. We calculate its area: 1.2 ∙ 1.2 = 1.44 m 2.
The weight of the sheet (depending on the thickness of the metal) is from 7 to 9 kg, so the relative load from it can vary from 4.9 (7/1.44) to 6.3 (9/1.44) kg/m2.

This means that replacement can be done without additional extension of the rafters, since the pressure will decrease by almost 4 times.

Video: dismantling and installation of the roof (slate - metal tiles)

Roof maintenance

Checking the condition of the roof covering is an important preventative measure. The more regular maintenance is performed, the more likely it is that your roof will last longer.

Upon completion of assembly, all objects are removed from the surface: cuttings of roofing sheets, screws, connecting elements and other loose objects. A clean roof surface is a prerequisite for the proper functioning of the roof. The same requirements apply to the drainage system. There should be no foreign objects, debris, accumulation of leaves, etc. in the gutters. The drainage system serves to automatically remove moisture from the roof surface, so monitoring its operation is also a preventive measure for roof maintenance.

Visual inspection of roofing covering

Inspection of roofing sheets is carried out at least once a year. To do this, it is not enough to assess the condition of the roof from the ground. You need to climb onto the roof and inspect the entire surface at close range. Particular attention is paid to the junction of the slopes with vertical walls, chimneys and other objects located on the roof. If problems are detected, they are eliminated as soon as possible.

Checking the serviceability of roof components

The components include structural elements of the roof. This:

The normal functioning of these elements depends general work and the durability of the entire roof, so you need to carefully monitor their safety. If the ridge is ventilated, you need to check the air intake openings for free air passage. It is not advisable to allow accumulation of water or snow in valleys. Drip rails and cornice strips are sometimes torn off by water and wind. It is necessary to ensure a strong fixation and return them to their original place in case of damage to the fastenings.

Monitoring the condition of the coating

Checking the status of colored and polymer coatings roofing is one of the most important tasks. The process of corrosion and destruction begins with small and unnoticeable damage, scratches and chips. If you eliminate them on time, you can count on the roof to last a long time. Most characteristic features Damaged coatings include bubbles, discoloration and mechanical damage. Their appearance indicates that it is time to repair the roof.

Drainage system

A system of gutters located along the roof slopes prevents atmospheric water from accumulating on it. If drainage systems do not function effectively enough, destructive consequences for the roof as a whole are inevitable. Having lingered at the edge of the slope, the water freezes or gets onto the inner surface of the roof. This leads to wetness of the wood from which the rafters and sheathing are mounted. The consequence is rot, fungus and mold, which will very soon destroy the wood structure and render the roof unusable. Checking the operation of gutters is a prerequisite for a roof inspection. If the channels are clogged with debris, leaves, etc., they need to be cleaned and restored to working order. It is best to carry out such work after the leaves fly off the trees, but before the onset of cold weather and frost.

Before the start of the winter season, gutters and pipes must be completely cleared of all foreign objects.

Roof cleaning

Experts recommend washing the roof with water and a foaming detergent every two years. Remove debris and dirt using a soft, long-bristle brush. It is possible to use pumps that supply water under pressure. The impact of a powerful jet of liquid allows you to remove stubborn dirt, sand and earth deposits. It is advisable to carry out the work in the warm season, when the roof dries quickly under the influence of the sun and warm air masses.

To wash the roof, you can use special equipment that supplies water under high pressure.

Video: roof cleaning

Coloring

An effective way to combat roof corrosion is the use of dyes with water-repellent properties. Typically, exterior paint is used that matches the existing color of the roofing.

The paint is applied with a brush or roller. If the damage has not affected the primer, one coat of paint is sufficient. If corrosion has penetrated to the metal, you need to carefully paint not only the affected area, but also the roof within a radius of 15–20 cm. The operation is carried out in dry weather, the paint is applied in two layers with a period of time until the first layer has completely dried.

Sometimes the roof is painted completely. This allows you to create additional protection for the roof from the adverse effects of the atmosphere. As practice has shown, the best paint - ship paint - can withstand up to 7 climatic cycles (years) on a metal roof. After this time, it is advisable to repeat the procedure. However, much depends on the region. In warm regions where severe frosts are rare, paint can last from 10 to 20 years.

It is more convenient to paint a roof made of stamped and wavy materials with a brush

The above applies to metal and asbestos-cement types of roofing. Roofs made of polycarbonate, roofing felt or soft tiles cannot be painted.

Video: painting a metal roof

Rules for roof operation in winter

In the cold season, when the air temperature drops below the water freezing threshold, seasonal factors must be taken into account.

Snow removal

With a properly planned and installed roof, problems with snow should not arise. This largely depends on the angle of the roof and the condition of the roof. It is necessary to ensure that zones with different textures do not form on the roof surface. For example, a seam roof needs to be painted periodically, since the paint, under the influence of the sun and the cycles of expansion and contraction of the metal, sooner or later cracks and crumbles. At the same time, the sliding of the snow mass slows down, the snow clings to the remaining paint and stays on the roof. Naturally, in this state of affairs, the home owner needs to monitor the condition of the roofing. The sooner you respond to damage, the fewer losses they will cost. But if snow still accumulates in a layer of more than 10–15 cm, you need to clean the roof. The same applies to ice on the eaves and edges of the slopes. If huge icicles hang from the roof, this indicates that the speed of water rolling off the roof is insufficient, so the water, without having time to move down, freezes in the cold and turns into ice. Second possible reason- clogged and icy gutters.

It is not always wise to undertake roof restoration on your own. The roof is a very important and vulnerable part of the building; it should not be taken lightly. Moreover, if not only the roof, but also the roof trusses need repair. By turning to professionals, you will receive qualified advice and guarantees for the work performed.

Installation of a gable roof is actively practiced in private construction, as it is the simplest and most affordable way to construct a reliable roof for a house. This article describes the main stages of installation, which can be performed independently, with a certain skill in roofing work.

Functional features of a gable roof

The structure of a gable roof consists of load-bearing elements (mauerlat, rafter system) and enclosing elements (roof). A gable roof (gable) has two roofing surfaces located at a certain slope to the outer walls of the building, which ensures natural drainage of moisture from melted snow and rainwater. According to SNiP, the angle of inclination of such a roof should be more than 5°.

The choice of roof slope angle is influenced by:

type of finishing material;
architectural features of the building;
climatic conditions of the construction area.

The construction of a gable roof with a large angle of inclination is usually practiced when relatively lightweight roofing materials are used and in regions without large wind loads, since the pitched roof of a building is a sail. In addition, a steep pitched roof is a practical option for areas with high rainfall - rain moisture is quickly and successfully removed from it, and accumulated snow slides down under its own weight.

Low-slope roofs experience minimal wind loads, but are very sensitive to snow loads. To avoid destruction of the structure under load from snow masses, in winter period The roof should be cleaned regularly.

In private construction, gable roofs are most often erected with an angle of inclination from 35 to 60°. This is the best option in terms of the ratio of roof resistance to atmospheric loads and reasonable costs for materials for installing the rafter system, as well as arranging the roofing pie.

Installation of a gable roof begins with the installation of a mauerlat or floor beams, depending on the type of rafter system chosen. Mauerlat acts as a foundation for roofing structure. It is this that allows you to evenly distribute the load (the weight of the rafter system itself, snow and wind loads, the weight of people servicing the roof), transferring it to the building structures of the structure.

Mauerlat is a timber made of coniferous species wood with a cross section of 150×150 mm (most often). When erecting a gable roof, it is mounted on two parallel walls. If the project provides for the installation of layered rafters with a ridge girder on supports, then the Mauerlat beam should also be laid on the middle load-bearing wall.

When building wooden houses, the mauerlat is not mounted - it is an element for laying on building structures made of brick, foam concrete blocks and other materials. On small buildings, the Mauerlat can be attached to the walls using forged wire embedded in the masonry. When building a house, it is practiced to install a monolithic beam with installed fasteners.

To make a beam at the top of the walls, it is mounted wooden formwork, metal reinforcement bars are attached (at least 2 pairs of parallel lines, one above the other). Using wire, studs or anchors are attached to the reinforcement. It is important to install them in increments of no more than 1 meter, strictly vertically. The prepared formwork is poured with concrete.

The length of the stud with a diameter of about 14 mm is determined based on the thickness of the monolithic beam, the thickness of the Mauerlat beam plus one or two layers of roofing felt waterproofing. In this case, when laying the Mauerlat, the studs must be at least 3 cm above its surface so that it is possible to secure the beam using nuts with wide washers.

When preparing to install a monolithic beam, you should determine in advance the installation location of the fasteners for the Mauerlat. The beam can be laid strictly along the axis of the beam or with a shift towards the inner or outside walls. To secure the Mauerlat, you need to make holes for the studs.

The Mauerlat is mounted at least 5 cm from the outer edge of the wall.

If roof frame It is planned to be made of metal elements; a channel or I-beam metal profile can act as a Mauerlat.

A rafter system with hanging rafters can be installed without a Mauerlat. In this case, the lower parts of the rafter legs are attached to the floor beam, which is laid across the walls. The beam acts as a tie and provides rigidity to the truss. Construction of a gable roof using this principle is usually used when constructing buildings with a small span, most often from timber or logs. It is not recommended to install support beams on walls made of piece materials, since a point load can destroy building structures.

Gable roof rafter system

The rafter system includes the rafters themselves (rafter legs), as well as a number of other elements, the installation of which is necessary to ensure structural rigidity:

crossbars;
runs (including ridge runs);
racks;
lying down;
spacers;
struts, etc.

Rafter systems can be mounted from wood or metal, or a combination of both types of materials.

Designing a rafter system is an important stage in preparation for construction. Errors in the design can lead to the roof collapsing over time under the influence of operational loads. On the other hand, having designed an excessive safety margin for the roof frame, you will have to spend extra money on its construction.

The design of the gable roof rafter system is based on the most stable and rigid geometric figure- triangle. When installing rafter systems of simple design, the rafters are made of timber with a cross-section from 40×150 mm to 100×250 mm. The choice of a specific value depends on the following factors:

installation step;
rafter leg length;
calculated load value.

In turn, the installation step of the rafter legs is influenced by the type of roofing pie - if installation is planned warm roof, then this parameter is selected taking into account the width of the roll or sheet insulation.

Types of rafter structures

When considering how to build a gable roof, it is necessary to pay attention to the specifics of constructing rafter systems of various designs - with hanging and layered rafters. Rafter legs are the main element of the frame of a gable roof. They serve as a support for the roofing pie. Hanging rafters do not have intermediate supports and rest only on the walls of the building. Layered rafters have additional points supports.

A truss, assembled from two rafter legs and a lower tie or an upper crossbar, is a structure that works in compression and bending. The bursting effect from the rafter legs mounted at an angle is compensated by the horizontal lintel. The higher the tie is mounted, the stronger and more rigidly one should be secured. This design allows you to cover even wide spans.

The upper part of the hanging rafters can be attached in various ways. The rigid fastening of the upper ends of the rafter legs is reinforced with the help of overhead elements made of wood or metal. When attaching the rafter legs to the mauerlat, a cutout (saddle) is made on the lower part of the rafter, after which the element is rigidly secured with nails and twisted wire. If rafters are installed on a floor beam, a stop is cut into the beam to prevent movement, and a single or double tooth is cut into the rafter. Installation is carried out using various metal fasteners.

There is no cutout in the Mauerlat timber so as not to weaken the load-bearing capacity of the roof support.

A roof frame with layered rafters is installed if the building has a middle load-bearing wall or columnar supports. The span between the supports should be no more than 6.5-7 meters. The width of the floor can be increased by installing additional supports: up to 11.5-12 meters with one additional support and up to 15-15.5 meters with two. To increase the rigidity of the rafter system and expand the opening between the supports, you should install a rack with struts under the ridge girder. The load on the roof is transferred by the middle part of the rafters to the internal supports, and by the lower ends to the external walls.

Installation of a rafter system with layered rafters is somewhat simpler than assembling and installing roof trusses. After installing the ridge girder on the gables of the building or special racks, the rafters are attached to it with the upper part.

In some cases, it is advisable to use both layered and hanging rafters when installing the roof frame.

The construction of the rafter system should be carried out using quality material to ensure the longevity of the roof. The lumber must have a strict geometric shape; wood defects are not allowed. To prevent wooden elements from warping after installation, the material must be well dried. Before installation, it is necessary to treat the prepared parts with a fire-retardant agent.

Roofing pie device

The question of how to properly build a gable roof, in particular, is related to the competent execution of the roofing pie. The functionality of the structure and its ability to provide reliable protection of the building from external influences depends on this.

When installing the roof, it is important to follow the designed pitch of the sheathing, having previously installed a counter-lattice to create a ventilation gap for the roofing pie. To ensure the necessary air circulation in the under-roof space, a ventilation duct is installed in the ridge part, and ventilation holes in the filing of eaves overhangs.

Particular attention is paid to reliable waterproofing of the roof, otherwise moisture condensed on wooden elements can cause rotting of the structures. If the attic of a gable roof is intended to be used as a living space, it is necessary to provide reliable insulation and vapor barrier for the roof.

To ensure the strength and durability of a gable roof, you should carefully approach the development of the project, the choice of materials and compliance with the work technology.

Installation of a gable roof, how to build it correctly, construction

We learn how to install a gable roof with our own hands. In this article you will learn how to properly build a gable roof and where its construction begins.

How the design of the rafter system works, which one is better to choose

The roof structure is considered the most complex component of a residential building in terms of design and installation. The roof is exposed to wind, precipitation and cold, therefore it must be airtight and durable to create comfortable living conditions. The main part of the roof is the rafter system, with the help of which the shape of the structure is created and set optimal angle tilt and waterproofing material is attached. The number of elements of the rafter system, as well as their location, is determined by the configuration of the roof.

Purpose of the rafter system

The rafter system is a certain number of supporting elements that create the geometry of the roof and frame, which gives rigidity to the roof structure and required slope. The main parameters of the components of the rafter system and their location are determined taking into account permanent and temporary loads.

In general, the rafter system is assigned the following tasks:

Creating the shape and angle of inclination. The location of the rafter legs determines the shape of the roof, hence the number of gables and slopes. In addition, with the help of these elements, the angle of inclination of the slopes is formed for the rapid removal of snow, melt and rain water.
Uniform distribution of the roof load on the load-bearing walls of the house. The rafters of the system are interconnected and distributed in the structure so that the weight of the roofing and snow mass is evenly transferred to the building frame, without skewing or deformation of the structure.
Creating conditions for normal ventilation and protection from moisture. The roof frame is assembled in such a way that air circulates freely in the under-roof space, and the material itself is reliably protected from condensation accumulation.

In addition, the rafter system serves as the basis on which the waterproofing material and lathing for the finishing coating are attached.

With the correct design of the rafter system, the roof will be reliable and durable and will last a long time. According to experts, a high-quality constructed frame has higher value Therefore, there is no need to save at this stage. Therefore, it is best to entrust the design of the roof and its installation to professional craftsmen.

Features of choice

The rafter system of a building consists of a specific set additional elements and has its own level of installation complexity. The number of auxiliary parts is determined taking into account the loads from the roofing material and some environmental factors.

When choosing the type of rafter system, you should pay attention to the following factors:

Features of the climate of the area where construction is planned. It is possible to protect the roof from destruction during snowfalls or heavy rainfall only if the average annual amount of precipitation is correctly calculated. The optimal roof option in snowy regions is a steep slope.
Wind load. The optimal design option is selected based on the wind rose at the construction site and the average speed of air gusts. In windy regions, slopes are made flatter.
Use of attic space. Creating a living space under the roof has great importance when choosing the shape of the rafter system.
Finish used. To roof covering performed its functions to the maximum, you need to choose the right angle of inclination of the slope, taking into account the shape and method of fastening the material.
Financial opportunities. Installation of a roof structure requires large financial investments, therefore, you need to choose the type of roof in accordance with the construction budget.

Types of rafter construction

No roof is complete without a rafter system. The quality of the roof structure largely depends on what is included in the roof truss system. Vertical supports, horizontal ties and rafter legs provide a reliable foundation and support for the roofing. To make the frame, it is necessary to use lightweight materials that do not load the frame at home. They must be durable, with high load-bearing capacity and good resistance to negative phenomena nature.

The most common options are:

Wooden frame. This rafter system has low weight and good strength, and the natural origin of the material ensures safety for residents and the environment. The frame is assembled from bars with a cross-section of 10*10 cm or 15*15 cm or boards 5*15 cm. Among the disadvantages of wood, poor resistance to moisture can be noted. In addition, the large length of the products contributes to their bending under their own weight.
Metal rafter system It is expensive, but when installing a large area of slopes and using heavy roofing materials, it becomes indispensable. Metallic profile has a high load-bearing capacity, which allows you to increase the distance between structural elements without reducing the strength characteristics. The only drawback of the metal is its poor corrosion resistance. To solve the problem in this case, metals that are resistant to this phenomenon are used.

Structural elements and details

All elements of the rafter system are interconnected. Thanks to this, the structure has rigidity and the necessary strength, and the weight from the roofing is evenly distributed across the load-bearing walls and partitions. The presence of certain structural elements, their cross-section and location depend on the selected roofing material, the angle of inclination of the slopes and the purpose of the attic space.

The main details of the rafter system are the following:

Mauerlat. This element is a rafter beam located on the top row or crown of the load-bearing walls of the house. For its manufacture, coniferous wood is used, which is hard and durable. The Mauerlat is fastened with metal pins or anchor bolts.
Sill. This element, made of timber, is located on the internal load-bearing partitions. The bench serves as a support for the posts, which are necessary to support the skate.
Racks- these are supports located vertically along the entire length of the beam and supporting the ridge or the central part of the truss.
Rafters located at a certain angle to the base of the roof. The support for the rafter legs is the mauerlat and ridge beam.
Bolt and tightening– necessary horizontal elements for paired connection of rafter legs. The crossbar tightens the rafters directly under the ridge girder, the tie rods are slightly lower.
Struts. These elements are placed at an angle to the rafter leg to prevent deflection. The upper edge of the brace rests against the rafter, the lower edge against the rack or tie.

To construct a simple rafter system design, it is enough to use a mauerlat, ridge beam and rafters. Increasing the level of complexity leads to the use of additional elements that make the structure more durable and resistant to deflections.

Types of rafter system

The architectural features of the structure have a great influence on the configuration of the roof, since the load from the roof structure must be evenly distributed between all load-bearing walls and partitions.

In this regard, the following types of rafter system are distinguished:

Layered rafter system. In this design, the roof frame rests directly on the load-bearing walls outside and inside the building. Supports on the internal load-bearing partitions are necessary to support the ridge girder. Layered rafters allow you to overlap large area while maintaining strength characteristics.
Hanging rafter system involves the support of the rafter legs only on the mauerlat. In the upper part, the rafters rest against each other without a ridge. These types of rafters are used when covering structures that do not have internal load-bearing partitions. The truss in this case has the shape of an equilateral triangle, therefore, stabilizing elements are not required.

The result of choosing the types of rafter system and their structural elements can be simple roof with one or two slopes, or more complex - hip and tent.

Construction of the rafter system: types of rafters, structural elements, roof details, what is included, parts

Construction and installation of a wooden rafter system

The roof of the building protects it from cold, rain and wind. This is the same important element like exterior walls and foundations. The rafter system is the supporting frame of the roof. It takes on all the loads: from structures, from snow and wind. To avoid problems during operation, the roof structure of the house must be strong and reliable. Do-it-yourself installation of a rafter system should only be done after careful preparation and study of all the necessary information.

Roof and roofing

Before you start installing the roof of a private house, you need to distinguish between two concepts. Non-professionals are often confused, but builders clearly distinguish between the definitions of roof and roofing. The roof is the entire structure that separates the building from the street above. The roof structure of a private house includes rafters, all other load-bearing elements, thermal insulation material, and roofing.

Rafters - load-bearing roof structures

The roof is the top part of the roof. It is also a roof covering. The installation of a roof requires careful selection of materials. After all, the reliability of waterproofing and comfort of living will depend on it.

System requirements

To properly install a rafter system with your own hands, you must take into account a certain set of rules. Without taking them into account, the structure will not be able to effectively resist negative influences from the outside.

First of all, it is worth considering strength. All elements must withstand the load without destruction. The design of the roof truss system involves a preliminary calculation of the load-bearing structures according to the first limit state. It is he who checks the elements of the rafter system for strength.

The rafter system must be strong and rigid

The second requirement is rigidity. The maximum deflection is taken into account here. The roof structure of a wooden house or any other should not sag too much. The permissible deformations in the middle of the span are equal to the length of this span divided by 200. Before construction begins, the structure of the rafter system must be calculated according to the second group of limit states - for rigidity.

Do-it-yourself roof raftering is done taking into account that the structure is light in weight. Otherwise, the load on the walls and foundations increases greatly. It is for this reason that wood has become widespread as a base material. The wooden rafter system has sufficient strength, but weighs relatively little. Attention should be paid not only to the roof structure, but also to choosing the right roofing material. It shouldn't be too heavy. Ceramic tiles have lost their popularity not only because of the cost, but also because the roof of the house, its walls and foundations must be reinforced to accommodate it.

The weight of the roofing material for a wooden rafter structure should not be too large

Special requirements are placed on the quality of the material. Manufacturing wooden elements should be made only from good raw materials. It is worth considering the following recommendations:

For the main elements, grade 1 or 2 wood is used. Grade 3 can only be used for sheathing and other small parts.
It is recommended to make rafter structures for pitched roofs from coniferous trees. They are more resistant to rot and other problems because they contain resin. With the same cross-section, the permissible span for hardwood will be less.
Before starting work, all elements must be treated with an antiseptic. This stage of preparation allows you to prevent many troubles in the future. You can also treat the wood with fire retardants if desired. This will increase fire resistance.
It is better to purchase wood from the northern regions, which is harvested in winter. This material is of the highest quality.

Parts of the structure

The rafter system diagram includes many elements. To understand drawings and correctly perceive information, you need to know at least the basic ones. So, what is the roof made of?

Ridge, cornice and slopes - the main part of the roof

First of all, these are the ridge, cornice and slopes. These elements are the main parts. The ridge is the topmost part of the structure. Cornice or overhang - bottom. Slopes are inclined surfaces that are located between the ridge and the cornice.

The construction of a rafter system requires knowledge of load-bearing elements. These include:

Mauerlat - timber that is laid along the edge of the walls of a building. The Mauerlat is needed to evenly transfer the load from the rafter legs, which are supported pointwise. Typically, timber with dimensions of 150x150 mm or 200x200 mm (for large buildings) is used for its manufacture.
Rafter legs are inclined beams that transfer the load from the roof's own weight, snow and wind to the mauerlat. Such beams are usually installed from the ridge to the eaves. But when constructing a hip roof, elements appear that have only one of the specified points. They are supported on a ridge or on a cornice. Such details are called spigots. They usually have the same cross-section as the rafters. In fact, sprigs are rafter legs cut off on one side.
Purlin - a beam on which roof elements rest. The purlin can be installed under the racks. Another option is a ridge girder (crossbar). The rafters rest on it at the top point. The cross-section of the purlin depends on its span, usually 200x200 mm.
Sloping legs are only needed for hip roofs. They are diagonal rafters resting on the Mauerlat at the corners. The cross-section is assumed to be enlarged, usually 150x200 or 100x200 mm.
The design of a wooden roof requires the presence of puffs, struts and racks. They are designed to reduce the load on the main elements. When building a house with your own hands, it is important to remember that the racks cannot be rested on the floor span. Installation is only possible on underlying walls or on purlins spanned between walls. Such elements can be mounted on the ceiling only if it is designed for such a load and reinforced in the required area.
The lathing is needed to make a base for the covering. For metal tiles and seam roofing, the lathing can be sparsely made of boards 32-40 mm thick. For bitumen shingles, you need a solid base made of boards 25-32 mm thick or moisture-resistant plywood.
In order to make the cornice overhang, install fillies. They become an extension of the rafters. The filly is attached to the rafters for a length of at least 1 m. The cross-section of the element is usually taken to be 50x100 mm.

Load-bearing elements of a hip roof

Another element of the rafter system is a truss. This is a one-piece structure that consists of rafters, tie rods, struts and racks, rigidly connected to each other. The truss has a triangular shape, and inside it is divided into several smaller triangles, which provides it with good stability.

Roof shapes

Pitched roofs come in different shapes. It is worth highlighting here:

single-pitched;
gable;
hipped (tent and hip);
broken

The most common are gable and hip roofs

The most common option is a gable or hipped hip roof. The first requires the construction of pediments. Broken lines are relevant when constructing an attic. At first the rafters go at a steep angle, and then at a smaller one. This technology allows you to raise the ceiling of the attic room. We also recommend reading about the rafter system for a half-hip roof.

Types of rafters

There are two designs:

with layered rafters;
with hanging rafters.

Installing a roof on a wooden house is only possible using the former. This is caused by two rules:

hanging rafters must be firmly attached to the mauerlat;
in a wooden house, the rafters must be hinged to the mauerlat.

These two statements contradict each other, so the rafter system of a wooden house can only contain layered elements.

Only layered rafters are installed in a wooden house

Layered beams are elements that rest on the Mauerlat at the lowest point and on the ridge girder at the top. This allows you to reduce the horizontal thrust that acts on the walls when the rafters try to move apart and take a horizontal position. Elements can be reinforced with racks or struts. In this case, contractions can be placed through one pair of legs.

Hanging tanks are supported only at the lowest point on the Mauerlat. At the top they just rest against each other. To prevent the system of wooden elements from moving apart, tightening must be done. It is better to install them on each pair of legs. This option is characterized by a strong thrust effect on the external walls, but it allows you to get more free space inside the attic.

Connections

Before you make a rafter system with your own hands, you need to carefully study the nodes. To build your home, you shouldn't save time or money. Only in this case the result will please you for many years.

Main rafter connection units

Mounting points for the roof truss system that deserve special attention, are represented by the following:

fastening the Mauerlat to the wall;
fastening the rafters to the mauerlat;
fastening the rafters at the top point;
splicing rafters along the length.

Mauerlat to the wall

This node can be performed in several ways. The choice largely depends on the wall material. The construction of a building made of brick, block or concrete allows the use of the following methods:

on the wire;
on staples;
on stiletto heels;
on anchors with the installation of a monolithic belt along the edge of the wall.

The connection of the Mauerlat to the wall during the construction of brick buildings is carried out using anchors

At wood construction The upper crown of the wall acts as a mauerlat. It is connected to the previous ones using a dowel. IN frame house Mauerlat is the top frame of the walls. It is fixed to the frame posts by cutting and metal corners with holes for self-tapping screws. Read more about attaching the Mauerlat to the wall.

Rafters to the mauerlat

Fastening is carried out in two ways:

rigid for buildings made of brick, concrete or concrete blocks;
hinged for wooden houses.

Rigid fastening can be with or without a notch. It is recommended to do the cutting on the rafters, and not on the mauerlat, since this weakens it. In both cases, the leg is rigidly fixed with nails, screws, staples or metal corners.

With rigid fastening, it is better to make a notch on the rafters and fix the structure with fasteners

For hinged fastening, a special part is used - a slide.. They allow the beam to move without obstacles when the walls of the building shrink.

The hinged connection allows the beam to move

Additionally, the rafter legs are attached to the wall. This is necessary to prevent the roof from being blown off by the wind. For fastening, use a twist of two wires with a diameter of 4 mm, fixed to the wall with an anchor or a ruff. In a wooden house, twisting can be replaced with staples. Fastening is carried out on each beam or through one.

At the ridge level

The layered elements rest on a ridge girder with a notch. Additionally, a board overlay is made on both sides. An overlay is also needed for hanging elements. It can be wooden or metal with holes for screws.

The ridge girder and rafters are connected using a notch

Splicing rafters

There are several methods for splicing roof rafters with your own hands. The choice between them largely depends on the experience of the master. The splice point is located at a distance of 0.15 span lengths from the support. In this case, not only the ridge girder and the Mauerlat are considered supports, but also the struts and racks.

Splicing rafters along the length

There are five ways:

To build a high-quality roof, you need to carefully study the technology, choose the right type of rafters and methods of connecting elements at important nodes. This is especially important when building a rafter system with your own hands.

Roof truss system for a private house: design and installation

How to properly make a wooden roof of a private house. Rafter system: structural elements, rafters, fastening points and do-it-yourself installation.

Types of gable roof truss system: for small and large houses

Design of a gable roof truss system

In cross-section, a gable roof is a triangle. It consists of two rectangular inclined planes. These two planes are connected at the highest point into a single system by a ridge beam (purlin).

Gable roof diagram

Now about the components of the system and their purpose:

Mauerlat is a beam that connects the roof and walls of a building, serves as a support for rafter legs and other elements of the system.
Rafter legs - they form the inclined planes of the roof and provide support for the sheathing under the roofing material.
Ridge purlin (bead or ridge) - combines two roof planes.
The tie is a transverse part that connects opposite rafter legs. Serves to increase structural rigidity and compensate for thrust loads.
The beds are bars located along the mauerlat. Redistribute the load from the roof.
Side purlins - support the rafter legs.
Racks - transfer the load from the purlins to the beams.

There are quite a few designs of rafter systems. First of all, they are divided into two groups - with layered and hanging rafters.

The difference in the design of layered and hanging rafters

With hanging rafters

Types of rafter systems with hanging rafters for different spans between load-bearing walls

Gable roof rafter system for small houses

Ridge knot and fastening of rafter legs to the backing board with a simple version of the system

For mansard roofs

Option with the installation of a crossbar - used when organizing a living space under the roof - an attic. In this case, it serves as the basis for lining the ceiling of the room below. For reliable operation of a system of this type, the crossbar cut must be hingeless (rigid). The best option is in a semi-frying pan (see picture below). Otherwise, the roof will become unstable to loads.

Rafter system of a gable roof with a raised tightening and a crossbar insertion unit

For large houses

If there is a significant distance between the two outer walls, a headstock and struts are installed. This design has high rigidity, since the loads are compensated.

Gable roof rafter system for a large span and ridge and rafter insertion units

With such a long span (up to 14 meters), it is difficult and expensive to make the tie in one piece, so it is made from two beams. It is connected by a straight or oblique cut (picture below).

Straight and oblique cut for connecting the tie

For reliable joining, the connection point is reinforced with a steel plate mounted on bolts. Its dimensions must be larger than the dimensions of the notch - the outermost bolts are screwed into solid wood at a distance of at least 5 cm from the edge of the notch.

Fastening struts for a rafter system with hanging rafters

With layered rafters

The simplest version of layered rafters

Non-thrust schemes and notch units

Houses made of logs or timber do not respond well to thrust loads. For them they are critical: the wall may fall apart. For wooden houses, the rafter system of a gable roof must be non-thrust. Let's talk about the types of such systems in more detail.

The simplest non-thrust rafter system diagram is shown in the photo below. In it, the rafter leg rests on the mauerlat. In this version, it bends without pushing the wall.

A simple non-braced gable roof system with layered rafters

The option with rafter legs fastened at the ridge part is much easier to assemble. They almost never push against the walls.

Option for attaching rafters without bracing to walls

Reinforcing the ridge assembly for heavy roofing material or for significant snow loads

Options for rafter systems with contractions

Schemes of rafter systems for gable roofs with contractions

They are attached to the rafter legs with bots or nails. Can be installed on one or both sides. See the figure below for attaching the screed to the rafters and ridge girder.

Attaching the screed to the rafters and ridge beams

In order for the system to be rigid and not “creep” even under emergency loads, it is enough in this option to ensure rigid fastening of the ridge beam. In the absence of the possibility of its horizontal displacement, the roof will withstand even significant loads.

Layered rafter systems with struts

Systems with rafter legs. There is a spacer system on top, a non-spacer system on the bottom. The correct cutting nodes for each are located nearby. Below - possible strut mounting schemes

But not in all houses the average load-bearing wall is located in the middle. In this case, it is possible to install struts with an angle of inclination relative to the horizon of 45-53°.

Rafter system with off-center vertical girder

System for houses with two internal load-bearing walls

Systems with rafter beams

In these systems, a ridge run is not installed: it provides expansion forces. The rafters in the upper part are connected to one another (cut and joined without gaps), the joints are reinforced with steel or wooden plates, which are nailed.

There is a version of the system with racks, but without rafter beams. Then a stand is nailed to each rafter leg, the other end of which rests on the intermediate load-bearing wall.

Fastening the rack and tightening in the rafter system without a rafter purlin

To fasten the racks, 150 mm long nails and 12 mm bolts are used. Dimensions and distances in the figure are indicated in millimeters.

Gable roof rafter system: device, components

A significant part of private houses are covered with a gable roof. To support it, you need a correctly selected rafter system and well-executed components.

The roof consists of rafters, sheathing and fencing, that is, the roof. Inclined surfaces are slopes and ribs. Horizontal parts: ridge, valley and valley. To organize drainage at the lower edge of the slope, gutters are sometimes used. The lower part of the slope between the groove and the edge is called the “descent”.

The wooden roof frame consists of the following structural elements: mauerlats, rafters and sheathing - (main and mandatory), tie, stand and struts (auxiliary) (Fig. 33).

Rice. 33. Structural elements of the roof frame: 1 – Mauerlat; 2 – rafter leg; 3 – tightening; 4 – stand; 5 – strut; 6 – lathing.

Mauerlat (popular name “uterus, matitsa”) is a beam with a cross-section of at least 10 x 10 cm or a log, hewn from the bottom side. The purpose of the Mauerlat is to serve as a support for the rafters and evenly distribute the load on the external walls. In log and cobblestone buildings, the role of the mauerlat is usually performed by the upper crown of the log house, and the clamps are nailed to the second crown from the top.

On walls made of lightweight masonry, lightweight concrete, frame and panel walls, a continuous mauerlat must be laid along their entire length. If the walls are made of massive materials (made of brick or stone), then a piece of log or beam 0.5 m long must be placed under each rafter leg. In this case, the ends of the clamps are attached to metal hooks, which, when laying the walls, are covered with 2-3 rows of bricks.

Rafters - load-bearing roof frame

The basis of the roof is rafters made of wooden beams, boards, and bars.

Rafters are a load-bearing structure that takes on the weight of the roof, snow and wind pressure; therefore, the wood from which the rafters are made should not have any defects: rot, wormholes, falling knots, cracks in the joint zones, cracks outside the joint zones with a depth of more than 0.25 of the thickness of the beam and a length of more than 0.25 of its length.

To make rafters, 40–60 mm thick softwood boards or beams are required. The lumber must be well dried, without defects, with a minimum number of knots. You can also use logs, but they are much heavier.

Plank rafters are easy to assemble. In this case, all connections are made on nails with or without overlays and liners. Notches, which weaken log and beam structures, are used here only to connect racks with purlins and beams in inclined rafters.

The cross-section of the rafters depends on the following factors:

– load created by the weight of the roof and snow;

– span size;

– rafter spacing;

– roof slope.

The cross-sectional size of the rafters is selected depending on their length and the distance between them (Table 2).

Table 2. The relationship between the length of the rafters, the thickness and the distance between them

The rafters can be fixed directly to the mauerlat, but if you need to cover a large span, the main frame elements alone will not be enough, here a tie, a stand and struts (both individually and combined) come to the rescue.

However, in any roof structure there are two main components: the enclosing (roof) and the load-bearing (rafters), which are divided into layered And hanging.

Layered rafters are beams that are similar to floor elements, but are installed not horizontally, but obliquely on supports of varying heights. They are supported by two external walls - pitched roof, or the outer and inner walls - at the gable. One more feature should be noted: the rafter legs of the opposite roof slopes are not necessarily attached in the same plane - they can rest on the ridge girder alternately (Fig. 34).

Rice. 34. Layered rafters: 1 – rafter leg; 2 – crossbar; 3 – attic floor.

The ends of the layered rafters rest on the walls of the building, and the middle part rests on intermediate supports. Layered rafters are suitable if the distance between the supports does not exceed 6.5 m. The presence of an additional support allows you to increase the width covered by the layered rafters to 12 m, and two supports - up to 15 m.

Hanging rafters rest only with their ends on the walls of the building (Fig. 35).

Rice. 35. Hanging rafters: 1 – mauerlat; 2 – rafter leg; 3 – tightening; 4 – grandma; 5 – strut.

Unlike layered ones, they transfer only vertical pressure to the Mauerlat. Hanging rafters are used when the roof span is 7–12 m and there are no additional supports. Hanging rafters are usually installed in buildings with light walls, as well as in buildings where there are no internal load-bearing walls.

The main elements of hanging rafters are rafter legs and lower chord tie-downs.

If you choose a roof structure with hanging rafters, all elements are rigidly connected, since they represent a single structure - a roof truss resting on two outer supports. Due to the lack of a middle support, the rafter legs rest against each other at the ridge. The consequence of this is the creation of significant horizontal pressure, called thrust. If the roof is not constructed correctly, the walls may even topple. The task of dampening horizontal pressure is performed by the lower chord of the truss - the tightening.

The choice of roof design depends on specific conditions. Figure 36 shows various truss structures depending on the size of the overlapped spans.

Rice. 36. Various designs of rafters: a – with a span of up to 5 m; b, d – up to 8 m; c, e – up to 10 m; g – up to 6 m; 1 – rafter leg; 2 – Mauerlat; 3 – ridge run; 4 – lying down; 5 – stand; 6 – overlap; 7 – tightening; 8 – crossbar; 9 – grandma.

Layered rafters are simple in design and do not require the use of lifting mechanisms during installation. Trusses with hanging rafters can be assembled on the ground, but then there is the problem of lifting them onto the structure being constructed. Although it is possible to install trusses directly on the house, using plank flooring and auxiliary braces and board joints.

In wooden cobblestone or log buildings, the rafter legs rest on the upper crowns (Fig. 37), in frame buildings - on the upper frame (Fig. 38).

Rice. 37. Supporting layered rafters in wooden cobblestone or log buildings: 1 – tenon; 2 – rafter leg.

Rice. 38. Support of layered rafters in wooden frame buildings: 1 – floor beam; 2 – rafter leg.

In stone houses, mauerlat is used as a support for the rafter legs - beams 140–160 mm thick (Fig. 39).

Rice. 39. Supporting layered rafters in stone buildings: 1 - Mauerlat; 2 – rafter leg; 3 – tightening; 4 – attic floor.

The Mauerlat can be located along the entire length of the building or placed only under the rafter leg.

If the rafter legs have a small cross-section, they may sag over time. To avoid this, it is necessary to use a special grille consisting of a rack, struts and a crossbar.

To make racks and struts, boards 150 mm wide and 25 mm thick or wooden plates obtained from logs, the diameter of which must be at least 130 mm, are used.

To secure the rafter leg, a tightening is used. When sliding along the tie, the rafter end may damage its integrity. To prevent slipping, it is recommended to cut the rafter leg into the tie using a tooth, a tenon, or both at the same time (Fig. 40).

Rice. 40. Connecting rafters with a tooth and a tenon: 1 – rafter leg; 2 – tightening; 3 – spike.

In addition, it is advisable to install the rafters at a distance of approximately 300–400 mm from the edge. In the process of inserting your foot into the end of the puff, you need to move the tooth as far as possible.

In the event that reinforced fastening of the rafters is required, it is advisable to use a double tooth (Fig. 41).

Rice. 41. Connecting rafters with a double tooth: 1 – rafter leg; 2 – tightening.

Most often, teeth of different sizes are used: the height of one tooth is 0.2 of the thickness of the puff, and the height of the other is 0.3. First, you need to make a stop and a tenon on the tightening, and an eye on the rafter (for the first tooth). For the second tooth, one stop is sufficient.

For additional fastening of the rafters, clamps and bolts are used in the tightening (Fig. 42).

Rice. 42. Connecting rafters with a bolt and a clamp: 1 – rafter leg; 2 – tightening; 3 – bolt; 4 – clamp.

Bolts are used less frequently, as they weaken the cross-section of the rafters and tie rods.

The installation is completed by constructing the ridge of the roof frame (Fig. 43), sheathing the eaves (the free part of the rafters protruding beyond the wall level - usually 40–50 cm), erecting gable walls and attaching sheathing from boards or bars.

Rice. 43. Ridge knot: a – simplified; b – complex: 1 – rafter leg; 2 – stand; 3 – strut; 4 – tightening; 5 – bracket, 6 – bolt; 7 – screed; 8 – scarf.

To the Mauerlat and purlin that make up the ridge assembly, clamps made of steel strip are attached with large nails or twists are made from wire with a diameter of 5–6 mm.

In order to connect a strut with a post in a complex ridge assembly, you need to hollow out a socket in the post and cut out a spike in the strut. To make the connection stronger, it is additionally reinforced with bolts and clamps.

The rafter legs are connected to the crossbar by a half-wood pan cut. To make the connection strong, it is necessary to secure it with a bolt, dowel or bracket (Fig. 44).

Rice. 44. Connection of the crossbar and the rafter leg: 1 – rafter leg; 2 – crossbar; 3 – bracket.

The roof must protect the walls of the building from the harmful effects of rain and snow, therefore the eaves overhang must have a length of at least 550 mm (Fig. 45).

Rice. 45. Roof slope: 1 – rafter leg; 2 – tightening; 3 – bracket.

The ends of the rafter legs are attached to the wall as follows: a tie-bundle is put on the rafter-tie assembly, which is tightened with the other end either on the attic floor beam or on a spike driven into the brick or stonework at a distance of about 30 cm from the top edge of the wall.

A cable tie is also called a twist, which is a piece of thick wire, preferably galvanized. In wooden log houses Instead of twisting, it is advisable to use an iron bracket. It is designed to connect the rafters with the second crown of the log house.

Reinforced concrete rafter legs of layered rafters are attached at one end to external wall building, and others to the precast concrete girder. The purlin is supported by brick columns.

Roof base

The base for the roof can be made in the form of sheathing or continuous flooring. It is used for laying and maintaining the roof. The sheathing can be continuous, but more often with a certain step, the size of which depends on the roofing material. When making the base, 2 basic requirements must be observed: all its elements must be tightly fastened to the supporting structures, and their joints above the rafters must be spaced apart.

It is advisable to use continuous flooring in cases where flat asbestos-cement tiles or rolled material are intended to be used as a covering. The flooring under the tiles is made of boards, the distance between which should not exceed 10 mm. The boards are laid out in one layer. Roll roofing arranged on a flat two-layer base, which consists of carefully fitted dry boards. A special lining made of roofing material RPP-300 or RPP-350 is placed between the floorings, which is necessary for protection from the wind.

Lathing with some spacing is used in cases where the covering is made of tiles, sheet steel, wood or corrugated asbestos-cement sheets. In this case, the sheathing is made of 50 x 50 mm bars. The distance between the bars should not exceed 200 mm.

The specified distance between boards or bars - lathing - must be strictly observed over the entire surface of the base. The widest of them must be placed under the joints of the roofing material, as well as at the ridge and eaves, and the thickest (15–35 mm thicker than others) - at the eaves. The width of the base under the gutter should be at least 750–800 mm, and under the eaves overhang with wall gutters - equal to the width of the overhang. In roof ridges and ridges, wooden blocks are installed on the edge.

Roof structure

The roof is the topmost cover of the roof, protecting all structural elements of the building from precipitation and draining water to the ground. Therefore, the main requirement for a roof is water resistance.

The roof can be made of various building materials: steel and asbestos-cement sheets, industrial rolls and local building materials (clay-straw, clay-reed, etc.).

The roof (roof covering) consists of:

– inclined planes – slopes;

– inclined ribs;

– horizontal ribs – ridge.

The places where the slopes intersect at an incoming angle are called “ valley" And " grooves", and the edges of the roof extending horizontally or obliquely beyond the building - cornice And gable overhangs respectively.

Atmospheric water from the slopes is collected in wall gutters, from which it enters water inlet funnels, then in drainpipes and finally in storm sewer.

Roofing elements can be laid both longitudinally and transversely, connecting them to the castle(roofing steel sheets) or overlapping(all other types of coatings).

According to the roof structure there are:

– single-layer– from steel sheets, asbestos-cement tiles and sheets (VO, VU), from strip stamped seam tiles;

– multilayer– from rolled materials, flat strip tiles, planks, shingles, shavings and shingles.

The number of layers in multi-layer roofs ranges from 2 to 5 depending on the chosen material; they are more labor-intensive and less economical.

If in multi-layer roofs each subsequent layer is laid in the transverse direction, then it must overlap the junction of the elements of the underlying layer. If it is placed in the longitudinal direction, then it completely covers the underlying layer with the overlap established by GOST.

Roof slope

The slope of the roof helps remove precipitation from the roof. It is expressed in degrees or percentage. As a rule, during the construction of buildings, their roofs are made flat with the same slope of the slopes.

The choice of covering material and the method of draining atmospheric water from the roof of the building depend on the selected roof slope - drainage, which can be organized (external or internal) or unorganized (external).

Outer organized drainage consists of gutters and external drainpipes. It is recommended for use in those climatic zones where the water in external drainpipes practically does not freeze.

Internal organized drainage consists of a water inlet, riser, outlet pipe and outlet. It can be used in all climate zones.

At unorganized drainage water flows along the entire length of the lower edge of the slope without any additional devices. This type of drainage is allowed in climate zones with little precipitation.

You can choose the right coating material and type of drainage in accordance with the roof slope using a special chart (Fig. 46).

Rice. 46. Schedule for choosing roofing material depending on the roof slope.

Straight arrows on the graph show the angle of inclination of the roof above the horizon line: on a semicircular scale it is determined in degrees, and on a vertical scale - in percentages. Arched arrows indicate the types of material that can be used at a given slope.

When installing the roof, you can use Table 3.

Table 3. Roof slope and relative value for each slope

Roof insulation

An attic is a room that is located between the roof and the upper (attic) floor of the building. As a rule, it is used for installing water tanks, laying heating pipes and placing prefabricated ducts and ventilation chambers. Moisture that accumulates in the attic penetrates from the lower floors and is removed using ventilation devices. We can say that the attic is an intermediate zone between the living space and the street.

If it is used as a living space, there is no intermediate zone. The moisture generated by breathing, bathing and cooking then takes the form of invisible steam.

Due to the pressure difference between the interior and the exterior, steam is formed, which tends to escape through the roof elements. The amount of steam in the air of a closed room is directly proportional to the temperature of the air in it. In other words, warm air contains much more vapor than cold air. When the room temperature drops, the air is unable to hold moisture, which settles in the form of water. This happens when water vapor from the inside penetrates into the lower layers of the roof, on which moisture settles.

To avoid this, it is necessary to seal the places where the roof does not fit tightly to the base, through which moisture from the room penetrates into the roof and contributes to its destruction. What can happen due to insufficient tightness of the steam and waterproofing layers.

To prevent this from happening, their installation should be carried out in compliance with all rules.

For roofs with slopes, there are the following types insulation:

– between the rafters;

– on the rafters;

- under the rafters.

Most often, the first method of insulation is chosen (Fig. 47), which is due to its relative simplicity.

Rice. 47. Insulation between rafters: a – with spacer tape; b – with wooden cladding and a protective layer; 1 – spacer tape; 2 – counter bars; 3 – sheathing; 4 – thermal insulation; 5 – waterproofing; 6 – tiles; 7 – ventilation ridge; 8 – wooden cladding; 9 - protective layer.

With this method, not a single section of the roof is left without insulation. The joints between roofs and walls, window frames, and chimney etc.

The ventilation space between the top of the thermal insulation and the waterproofing must be at least 2 cm. In the process of stretching the waterproofing layer, it is necessary to ensure that it does not sag. Sagging areas of this layer will create an obstacle to normal air ventilation. Mineral fiber can be used as a waterproofing layer, which tends to increase the volume when laid by 10–30%. Therefore, when installing insulation, it is necessary to reduce its consumption by the same amount. If the depth of the rafters is not sufficient for laying insulation and does not allow space for ventilation, you can build them up using boards and beams.

Another way to free up ventilation space is to divide the insulating layer into two parts. One half is laid between the rafters, and the other above them.

One of the latest achievements of science includes insulating systems with diffusion spacer tape. As a result of their use, the need to create a space between thermal insulation and waterproofing is eliminated.

Insulation on rafters (Fig. 48) has a number of advantages.

Rice. 48. Insulation on rafters: 1 – sheathing; 2 – protective layer; 3 – counter bars; 4 – thermal insulation.

Firstly, it itself is not a conductor of heat. The insulating shell is located above the load-bearing part of the roof and protects it from exposure to atmospheric phenomena. In addition, with this type of insulation, the rafters in the room remain visible, which gives the attic space a rustic coziness.

Insulation under the rafters (Fig. 49) has the following advantage: it is made continuous, no space for ventilation is required. For this type of insulation, mineral fiber panels are used. Its disadvantage is the reduction in the volume of the attic.

Rice. 49. Insulation under the rafters: a – with spacer tape; b – with sheathing and protective layer.

If the installation of the attic space is carried out in a house that was built a long time ago, you should check the condition of all roof elements.

Old rafters can be attacked by insects. And at first glance wooden rafters do not give the impression of being damaged. However, when sawing a piece of wood, insect passages may appear.

Heavily damaged roof elements must be replaced, the rest must be sanitized with special compounds made on the basis of artificial resins. These measures will help ensure high-quality hydro- and thermal insulation of the roof.

The choice of roofing material and roof design is made during the development of the building project. All this depends on the design of the building, its construction and purpose. Roofing elements, materials for installation, and the choice of roof type depend on many factors. First of all, these are climatic and geographical conditions, architectural requirements for the structure and the degree of capital of the building. The roof design of a bathhouse or some outbuilding may be completely different from that of a residential building.

The roof has three main elements: rafters, sheathing and a protective part, that is, the roof. The horizontal parts are called valley, ridge and valley. Slopes and ribs act as inclined surfaces. Gutters are sometimes used to provide drainage at the bottom edge of the slope.

Roof structural elements

Now let's look at what the roof and its protective covering - the roof - are made of.

It is known that all buildings have at least some kind of upper ceiling, and in civilized buildings it comes in two types:

Attic (or upper) floor. Serves to protect against cooling.
Roof. Provides protection for the entire building from precipitation, sun and wind.

Roof structural elements

Main elements of the roof:

One of the main elements is the slope - the so-called system of inclined planes, which facilitates the trouble-free removal of water deposits from the roof. We can say that it ensures its waterproofness.
Ribs are protruding corners that appear due to the intersection of slopes.
The endova, or valley, is internal corners, formed at the intersection of two slopes. One of the main structural elements.
Descent – this is the name of the lower part of the slope.
The drip edge is the lower part of the descent, which protects the cornice and wall from water ingress.

Behind the edge of the outer walls of the building protrudes the horizontal part of the slope, which is called the eaves overhang.
There is also a front overhang, which is the inclined part of the slope.
A gutter must be made at the edge of the slope - a place for collecting melt and rain water.

The liquid collected by the gutters is removed and discharged down using a drain, which comes in two types:

external, in which drainpipes are installed near the outer wall of the building;
internal - drainpipes are mounted inside the walls, most often used if a flat roof is installed.

However, gutters and downspouts may not be used if the height of the building is small and the area of the structure is small. Water will fall from the roof edge directly to the ground.

Roofing elements are laid in the longitudinal or transverse direction. Sheets of roofing steel are connected into a lock, and all other coverings are overlapped.

A chart that helps you choose covering material and type of drainage depending on the roof slope.

An important parameter of the roof is the slope, which protects the roof from the accumulation of precipitation, especially snow. It is expressed mainly in degrees, but in the drawings you can also see the slope as a percentage. The coating material and the method of removing moisture from the roof depend on this indicator.

Geometric roof shapes

Surely for some people uninitiated in construction it will be a surprise how many different types there are geometric shapes roofs. Of course, each of them is used for a specific type of building:

Single pitch roof. Used for fairly simple buildings that do not have drainpipes or snow dumping. It is also optimal for those buildings that adjoin the longitudinal side of a larger building. Indispensable for auxiliary buildings: baths, toilets, gazebos, etc. The simplest type of roofing that does not require large quantity material, but at the same time one of the most durable.
Gable, or gable. This is a design of two inclined slopes. The triangular space between the slopes is called gables or gables. One of the most popular types of roofs, used in the construction of houses, cottages and buildings with a small number of floors.

Roofs are different, as this picture shows. There is no such thing as a gable roof. The conical gable design looks the most original

Four-slope. It is divided into hip and tent. It is used mainly in rural and country construction.
Dome. Used to cover buildings. One of the oldest types of roof. Often used in the construction of hotels or pavilions.
Attic. A type of gable roof.
Vaulted. Used to cover industrial or public buildings with a rectangular plan.
Conical. Indispensable in the construction of buildings round shape.
Pyramidal. “Serves” buildings with a square or polygonal plan.

As you can see, depending on the shape and purpose of the building, one or another type of roof is used. For a toilet or bathhouse, using a hipped structure is complete stupidity; in the same way, for multi-story buildings, a pitched roof is not a suitable option.

In addition to their shape, roofs are also divided according to their design. According to this indicator, they can be attic or non-attic. Attic (separate) roofs, depending on the type of building, can be insulated or made cold. In combined (atticless) roofs, load-bearing elements cover the upper floor of the building. Attic roofs are built without ventilation or with full or partial ventilation.

The difference between an attic and a non-attic roof. In roofs without an attic, the load-bearing wall takes the load.

As we have already mentioned, the choice of roof shape depends on the architectural design, type of roofing material, etc. The slope of the slopes and the features of the supporting structure decide a lot. We cannot neglect climatic conditions. In warm areas, roofs with a slight slope are popular, and in snowy conditions - with a steep slope and a small overhang so that snow precipitation does not linger on the roof. In strong wind conditions, the structure should be flat to reduce windage.

Rafters

As the base of any roof, rafters made of wooden planks or bars. This is a load-bearing structure that takes the weight of the roof upon itself, so it is always made of high-quality wood, without cracks or rot. The material for making rafters is softwood boards or beams. They must be perfectly dried and contain a minimum number of knots. It is acceptable to use logs, but they are much heavier.

The support for the rafters is the mauerlat. This is a beam with a cross-section of at least 10x10 cm or a log, necessarily hewn from the bottom side. This element is also designed to ensure that the load on the load-bearing walls is distributed evenly. The upper crown of a log house can be used as a mauerlat for the construction of cobblestone and log buildings.

Rafter diagram for a gable roof. Mauerlat as a support is required.

The cross-section of the rafters is calculated additionally, and it depends on several indicators: the load created by the weight of the roof and snow precipitation, the pitch of the rafters, the size of the span and the slope of the roof. According to the method of installation, rafters are divided into two types: layered and hanging. The first ones are installed obliquely on supports, which serve as external walls (for a single-pitched roof) or internal and external walls (for a gable roof). Hanging rafters rest only on the walls of the building. They are installed in those buildings where there are no additional supports and internal load-bearing walls.

Sheathing is used as a base for supporting and laying the roof. It can be continuous, but most often it is done with some step, which depends on the material. The main requirements for the manufacture of the base:

all parts must be tightly fixed to the supporting structure;
The joints above the rafters must be spaced apart.

Lathing with a step is used when the covering is made of asbestos-cement sheets, tiles or sheet steel.

Solid flooring can also be used as a base, but it is only suitable for rolled material or flat asbestos-cement tiles. The distance between boards or beams should be the same over the entire surface.

The sheathing is made from edged boards. Depending on the type of roof intended and the roof structure, it can be solid or thin.

General conclusions

The roof structure, although it seems complex, nevertheless contains elements, each of which performs its own functions. A lot depends on the design of the entire roof, which is developed during the design of the building or planning the renovation.

The roof of your house will be reliable and durable only when all components are correctly and correctly installed: roofing, ribs, ridges, gutters, connections to pipes and other components. It is better to buy a roof in a complete package, which contains all the necessary materials and accessories, and from one manufacturer.

Roof of a complex configuration with a fantasy design

Private architects or design bureaus should design buildings, since only they have the necessary permission to do so. The finished house project contains a roof plan, all components and details of the roof structure. Direct construction should only be trusted to professionals who will carry out high-quality installation and will provide a guarantee for the work performed.

Classification of roofs: design, types, shapes, elements. Structural elements of the roof - what it consists of and what materials are made from Composite roof

Design of a gable roof truss system

With hanging rafters

Gable roof rafter system for small houses

For mansard roofs

For large houses

With layered rafters

Non-thrust schemes and notch units

Options for rafter systems with contractions

Layered rafter systems with struts

System for houses with two internal load-bearing walls

What is a roof and what does it consist of?

Roofing device

Types of roofing

Roof installation

Video: DIY metal profile installation

Removal and replacement of the roof

Video: dismantling and installation of the roof (slate - metal tiles)

Roof maintenance

Visual inspection of roofing covering

Checking the serviceability of roof components

Monitoring the condition of the coating

Drainage system

Roof cleaning

Video: roof cleaning

Coloring

Video: painting a metal roof

Rules for roof operation in winter

Snow removal

Functional features of a gable roof

Gable roof rafter system

How the design of the rafter system works, which one is better to choose

Purpose of the rafter system

Features of choice

Types of rafter construction

Structural elements and details

Types of rafter system

Construction and installation of a wooden rafter system

Roof and roofing

System requirements

Parts of the structure

Roof shapes

Types of rafters

Connections

Types of gable roof truss system: for small and large houses

Design of a gable roof truss system

With hanging rafters

With layered rafters

Layered rafter systems with struts

System for houses with two internal load-bearing walls

Roof structural elements

Geometric roof shapes

Rafters

General conclusions

Latest

You need to know this