Independent construction of the roof of a private house. Roof frame: installation technology How to make a roof frame for a house
During the construction of any type of structure, very strict requirements are imposed on its load-bearing elements in relation to strength. The main carrier components are:
- foundation;
- walls;
- roof.
Let's take a closer look at how to make a roof frame with your own hands, and what installation methods are currently used and what are the options for saving on construction work.
There are certain types of frames, and the choice of one of them depends entirely on the type of roof, what kind of coating will be used and what the building is intended for.
What are the frameworks?
- wood frames - this is a truss-type system that is used to create roofs in the construction of residential buildings and is the most common type;
- metal frames. Frames of this type are mainly used in the construction of industrial structures, since their installation is very costly and involves huge volumes and areas;
- Reinforced concrete frames are flat roofs, the supporting type of which is made of slabs.
Types of truss systems
Before you start building a roof frame with your own hands, you should decide on the type of your truss system, that is, which one you will use for yourself. The main purpose of the rafters in the construction of any type of pitched roof can be called a support. Rafters (rafter legs) are wooden beams with a section of 150 by 50 mm. Sheathing and roofing should be laid on the beams.
There are such types of frames for roofs, it all depends on the type of rafters:
- layered type;
- hanging type.
Any of these types can be used to build a private house, they differ only in that a Mauerlat is used as a support for a hanging type system. When you use layer-type rafters, then their part on top will rest on the main load-bearing wall, and not connect to each other.
To select any of the systems, the design and planning parameters of the structure should be taken into account. For example, when the distance between the walls of the bearing type for supports is less than 6 meters and 6 meters, it would be better to use a hanging type frame for the roof. For a distance of more than six meters between the supporting walls, it would be better to use a layered type system and build additional intermediate walls, which will be located in the center of the structure. So, the rafters will not start to sag if the spans are too large. This condition can only be attributed to wooden frames; for metal frames, additional walls are not required.
Installation Features
Roof installation can be carried out in two ways:
- Use of ready farms. The finished trusses themselves are reinforced rafters, which are installed using racks, struts and puffs. Initially, it is necessary to assemble the entire supporting structure, which consists of the same parts, and then it is placed on the roof of an already built building box. This type of installation will take little time, but it will require lifting equipment, and this will entail additional and very high costs. Such an installation should be carried out for roofs that have long overhangs and do not have supports.
- The second method is to assemble the entire frame directly on the roof of the building. This method is affordable and less expensive, but it will take much more time to complete it. The whole assembly process consists of several stages, but everything can be done by hand.
When designing a frame scheme for a roof, the following important factors must be considered:
- The whole structure must withstand loads of different magnitudes, which can include the mass of the roof itself and its other components, as well as the mass of snow in winter, gusts of wind, leaves in autumn and other moments;
- It is necessary to select a roofing coating based on the maximum level of water resistance, especially if you live in regions with higher humidity;
- Thermal insulation should be done with the smallest losses. To do this, it is necessary to mount the waterproofing correctly and correctly, as well as think about the vapor barrier and ventilation system of the space under the roof;
- The attic space must be ventilated. This makes it possible to prevent damage to the bearing-type parts of the entire structure, which will increase the period of operation of the structure itself.
Material selection
If you have a desire to learn how you can make a roof frame yourself, then you need to have certain materials and tools for this.
In order to complete all the work you will need to have the following:
- beams with a section of 150 to 50 per rafters;
- beams with a section of 100 to 100 for arranging a Mauerlat (for this it would be better to buy a coniferous tree that was harvested in winter and does not have any flaws;
- slats with a section of 40 to 40 for arranging the crate;
- fastener studs used to fix the Mauerlat;
- for rafters, studs with a dimension of 8 and 10 mm;
- brackets and brackets;
- wood screws;
- planer, drill, hammer;
- level and file;
- gloves, tape measure;
- antiseptic for wood;
- flame retardants.
If you treat wood parts in the entire structure with special antiseptics, as well as when using flame retardants, the period of operation of the entire building increases and the level of flammability decreases, which minimizes the risk of fire.
assembling the frame with a gas gun
Advice
In many ways, installation is simplified and accelerated when using a gas gun. In this video, the roof frame is made very simply and quickly using modern equipment. If you build once, then you can rent such equipment.
To build a frame from a metal profile, you will need other tools, but since the mass of materials and the level of complexity of execution does not make it possible to do such work on your own, it is better to build wooden frames.
Gable roof frame
After you have purchased all the necessary materials, as well as prepared the tool, processed the wooden parts with special compounds, then you can safely begin installation. The construction of a gable roof frame must begin with the installation of a Mauerlat. This beam will serve as a distributor, and distribute the load from the rafters to the walls of the bearing type. Usually, the mauerlat is laid on a concrete base on the inside of the bearing walls.
In order for the tree not to draw moisture out of the concrete coating, and the coating itself does not crumble after that, several layers of roofing material must be laid under the bars. From the side of the outer wall, brickwork should be arranged to the place where the Mauerlat begins, and the Mauerlat itself is attached to concrete with studs and nuts.
Rafter system
After the base has been erected and strengthened, it is possible to carry out the construction of the frame, in other words, begin the installation of rafters.
Installation of rafters consists of the following steps:
- determine the pitch of the rafters. Usually, it is equal to 80-90 cm, and this corresponds to the dimensions of the crate bars;
- in order to fix the rafters, it is necessary to initially make holes in the Mauerlat;
- as a rule, the arrangement of the frame for roofs must be started from the pediment of the entire building, in other words, from the end part. End-type rafters are installed on both sides of the roof, and then a cord is pulled from ridge to ridge. This lace will become an assistant when you expose elements in the gaps;
- all legs of the rafters should be fixed to the Mauerlat using steel brackets and staples. The legs of the rafters should go beyond the perimeter of the building by 40 centimeters. If you fail to build an overhang of the rafters, then you can build it up with the help of special filly bars that have a smaller section, fixing them on the rafters with nails;
- to fix the lower part of the legs of the rafters, use a harness that will rest on the Mauerlat. When the rafter is not long enough, you need to build it up by placing another overlapping beam on it. The overlap should be as large as possible, at least one meter, otherwise the roof will lose its rigidity;
- frames with spans of six meters cannot be installed without arranging puffs between the legs of the rafters. They are mounted between the supports of the rafters so that the design visually resembles the letter "A";
- after all the rafters are installed, they should be fixed exactly vertically. Here a ridge-type beam is used, placing it on top of the structure;
- and the last stage is the crate device. If you intend to use a soft-type roofing material, then you should make a solid-type sheathing from plywood or OSB boards, which have high moisture-resistant properties. If you are going to use such material for roofing as corrugated board, slate or metal tiles, then the crate is made of a transverse type. To increase the level of strength, a continuous crate is equipped near the skates, regardless of the type of coating.
Design features
It is clear how to equip a roof frame, but in order for the result of your work to please you for many years, some features should be taken into account during construction.
- It is worth remembering that the step for installing the rafter legs and the selection of the section are interrelated quantities. In other words, if the section is smaller for beams of the bearing type, then the step is accordingly smaller. This should be remembered and known, and will be useful to you in the event that the dimensions of the materials do not correspond to the loads.
- The rafters can be placed freely or loaded, that is, support the floor beam.
- All nodes are connected and fastened to the maximum securely, this will help provide an additional level of rigidity and at the same time it is worth using reinforcing type linings.
- The rafters are attached to the Mauerlat by several methods. With the help of notches, it is possible to provide a much tighter fixation, and specialized sliding-type fasteners are great for log-type houses.
- To protect the outer walls, the foundation and blind areas are perfect, the edges of the roof should go beyond the box by at least 40 cm, and in this case it is better to protect parts from the ends of the rafters with a wind (frontal) board.
- When using hanging type rafters, it is worth remembering about the load that goes to the walls, so you should fasten the legs of the rafters with a puff. It can be a beam or a floor beam.
- The step in the crate should be selected according to the parameters of the coating. Different types of roof coverings differ in their ranges of use, depending on the level of inclination of the slopes.
Features of the construction of a gable type roof, and some tips on building a frame, you can see in the video:
features of the construction of the frame for a gable roof
But it is unacceptable to relax at this step. Small miscalculations will lead to the need for premature repairs, and if you make a serious mistake, the entire building may collapse. Find out what materials are suitable for the selected project, think over the type of roof, decide whether an attic space is needed in the building and whether it will be used. Read the quick installation instructions to do everything yourself or check the work of the masters.
Preparatory work
The roof of a frame house with a flat roof can be built with your own hands, but it is better not to take on more complex projects alone. Even at the stage of designing a house, it is important to consider:
- roof shape.
- The slopes that will need to be done for the ramps.
- Roofing material.
- Device truss system.
- The distance between the rafters and their cross section.
- Lathing step.
- Materials for insulation, vapor barrier, waterproofing.
Types of roofs in shape
The shape of the roof of a frame house is:
- Flat shed - the cheapest and easiest to install.
- Gable - suitable for one-story and two-story houses with a small area and rectangular buildings.
- Broken line - ideal for projects with an attic.
- Four-pitched - used for buildings of any type, resistant to wind loads.
- Multi-tweezer - a complex design consisting of several slopes. Suitable for projects of multi-level houses.
- Spire-shaped - original, ideal for snowy regions, but requires complex calculations.
When choosing a roof shape, consider:
- Area, number of storeys, general project and design of the house.
- Selected roofing material.
- Climatic conditions of the region (wind, snow).
- Budget.
It should be noted that the safest is recognized the slope of the slopes, which is from 30 to 45 degrees.
Main criteria for material selection
For the roof of a frame house, you can choose various roofing materials, but preference should be given to lighter ones. This rule is especially important if the foundation is not designed for heavy loads.
- bituminous tiles;
- polymer sand tiles;
- corrugated board;
- slate;
- metal tiles;
- cement-sand tiles.
For heavy roofing materials, the crate should be made more frequent. Additionally, you need to use a layer of waterproofing material. It is necessary to follow the step of fixing the main roofing material. If you do it more often, then the likelihood of a roof leaking can be minimized.
When installing roofing materials, it is important to adhere to the following tilt angles:
- Minimum 10 degrees for corrugated board.
- From 12 and 60 degrees for slate.
- For euroslate, the lower figure is 6 degrees.
- For ceramic tiles - from 18 to 60 degrees. The same indicator should be followed when fixing polymer-sand tiles.
- For shingles - more than 12 degrees.
- Metal tiles require installation at an angle of more than 15 degrees.
Roof installation features
The easiest way is to make a shed roof with your own hands, other options will require knowledge and experience.
Roof construction includes the following steps:
- Installation of the truss system.
- Installation of material for insulation, vapor barrier and waterproofing.
- Lathing and counter lathing.
- Installation of roofing material.
The roof truss system of a frame house must be correctly calculated. For this, the section, step and the length itself are analyzed. Builders note that, first of all, the strength of the structure depends on the following parameters:
The cross section can be selected according to special construction tables or do all the calculations yourself.
Installation of the truss system
The roof of a frame house will last a long time if the ceiling beams are correctly and firmly fixed. For this, it is recommended to use a beam with a section of 50 by 150 (200) mm.
At the first stage, you will need to create a special template for rafter legs. To do this, all manipulations should be performed according to the scheme:
- Take two boards and place them in relation to each other at a right angle. For a strong fixation, it is allowed to use ordinary nails.
- The resulting element is additionally fixed on one edge of the Mauerlat.
- By moving the boards, set the corner, which will later be used as a slope.
- From the edge of the wall retreat at least 40 centimeters. The resulting space will be used for water runoff.
- After obtaining the required angle, securely fix the beam. Builders are advised to mark the cut line with a simple pencil.
After preparing several templates, you will need to connect two pairs of rafters together. Fastening is done on both sides. If necessary, legs can also be added separately in the future.
For docking, ordinary thick bolts are quite suitable. This option is several times safer, especially when compared with nailing. Between two adjacent legs, you will additionally need to install a transverse mounting option.
A shed frame house will be protected from the weather if all roof elements are installed correctly. To do this, a rope is pulled between the side rafters. It will serve as a beacon and a guideline by which the level is checked. Further elements are fixed at a distance of 60 or 80 centimeters. This step is recommended to be followed constantly.
Pre-calculations are made necessary to determine the number of rafters. Between the individual elements of the truss truss, you will need to nail two boards. They will provide the necessary fixation. For additional protection against atmospheric precipitation, install diffuse membrane.
The size and pitch of the crate can be calculated independently using formulas. In this case, it is imperative to take into account the bias and features of a particular material. For the construction of the crate, it is allowed to choose a beam, the cross section of which is from 40 to 50 mm.
Laying roofing material
At the first stage, the cornice strip is mounted. For this, it is advisable to use self-tapping screws. Only after that it is allowed to lift the metal tile onto the roof. It is also fixed on the cornice strip with self-tapping screws.
There are situations when one sheet is not enough. In this case, it is advisable to increase the length. To do this, the fastening is overlapped. According to this technology, all the material is laid.
Detailed and accessible about the installation of the roof is described in the video.
Roof construction is one of the most important stages in the construction of a house. The rafter part of the roof requires special attention, both at the design stage and at the stage of direct assembly. Before proceeding with the installation of the roof truss system, you will have to understand all the intricacies of the issue. Calculations are best left to professionals. In the design of the roof, a huge number of factors are taken into account, these are wind and snow loads, the weight of the truss system and roofing materials, the geometry and technical parameters of the structure.
There are specialized computer programs for calculating the optimal roof design and counting the amount of building materials needed. Loads and impacts can be specified in the SNiP 2.01.07-85 of the same name. Adjustment coefficients for individual regions are also given there. Almost all calculations need to be increased by 10% to create a margin of safety.
After the roof project is ready, the question arises of the correct installation of the roof rafters. Roof trusses, in most cases, are a triangle. This is the most durable and cost-effective form. Rafters can be made of various materials: wood, metal or reinforced concrete.
A combination of different materials in one design is also allowed.
Rafter connections
Roof trusses can be made independently, in accordance with the project, or ordered factory-made. Making to order does not impose restrictions on the shape, volume and size. At the factory, both the entire truss system and individual elements for subsequent assembly directly on site can be made. Fastening industrial rafters is usually performed using metal plates provided by the manufacturer. Rafters made independently are connected by a groove-thorn pattern and reinforced with nails, bolts, brackets and clamps.
It must be borne in mind that the wooden elements of the truss system must have a moisture content of no higher than 20%. The material may shrink. Fastening roof rafters with nails or staples is only permissible for dry material. If the percentage of moisture causes even the slightest doubt, it is worth choosing bolting. They can be tightened over time, but the bolt holes weaken the strength of the rafters.
Design requirements
There are three main requirements for the design of the roof truss:
- Rigidity;
- Optimal weight;
- The quality of materials.
The requirement of rigidity directly relates to the joints and fastenings of all elements of the truss system. As mentioned above, the rafter system is a system of triangular trusses installed parallel to each other. The triangular shape itself provides structural rigidity, but the rafters must be securely fastened relative to each other. Even the slightest mobility can lead to disastrous consequences.
The requirement of weight optimality is fulfilled at the stages of calculations. The total weight is made up of all elements of the truss system, hydro-steam and thermal insulation, roofing material. For example, natural tiles weigh 40-60 kg/m2, slate 10-14 kg/m2, shingles 6-8 kg/m2, and metal tiles 3.5-4.5 kg/m2. supporting walls of the building, taking into account constant and variable loads, because the effects of wind and the volume of snow will be added to the mass of the roof itself.
The quality of materials can be assessed in several ways. The grade of wood should be 1-3 grades, with a minimum number of knots. Preference is given to conifers. The allowable length of the board of their coniferous wood is 6.5 m, of hardwood - 4.5. Mauerlat, pillows and girders are made from hardwood.
Regardless of the cost and quality of materials, it is necessary to remember about the waterproofing and treatment of all wooden elements with antiseptics and flame retardants.
The main parts of the construction of the truss system
Mauerlat- this is the basis of the truss system. Mauerlat evenly distributes the load on the outer walls of the building.
rafter leg- rigidly fixes the elements of the roof, is responsible for the angle of inclination of the slope. The appearance of the roof depends on the location of the rafter legs.
Run- fastens the rafter legs. The ridge run is located at the top, the side runs are on the side.
puff- fastens the rafter legs in the lower part and prevents them from "driving around". Racks and struts - provide the truss system with additional rigidity.
Sill- located below, parallel to the ridge and serves as a base and support for racks and struts.
crate- arranged perpendicular to the rafter legs. It is made from boards or bars. It is designed to transfer the load from the roofing material to the rafter legs and serve as the basis for the roofing material.
Part Names Roof ridge- the junction of two roof slopes. A continuous crate is stuffed along the ridge to reinforce this part of the structure.
Filly- are arranged to organize an overhang.
Eaves- this is the distance from the wall of the house to the edge of the roof, designed to protect the house from excessive rainfall on the walls.
Forms of roofs and truss systems
The shape of the roof is determined primarily by the geometry of the building. Different forms of roofs can be combined in cases of complex buildings.
Roof shapes Roofs with a slope of 2.5 to 10 degrees are called flat. Not every building can be covered with a flat roof. The dimensions of the building and variable loads characteristic of the construction region are important.
Shed roofing has the simplest truss system and a slope of 14 to 26 degrees. Such a roofing device is ideal for outbuildings, verandas, small structures in which one of the parallel walls is higher than the other.
shed roof A roof with two slopes has a more complex system of rafters. The under-roof space can be both non-residential, attic, and attic, landscaped. The slope of the gable roof is taken in the range from 14 to 60 degrees. The gable roof truss systems also differ in type. They are hanging and layered, depending on the dimensions and geometry of the building.
Types of truss systems A four-pitched roof is called a hip or half-hip roof. The slope of such a roof is allowed from 20 to 60 degrees, and the length of the overlapped span can be up to 12 meters. This design requires internal supports. The absence of gables significantly saves materials, but the installation and installation of the truss system requires more attention and money than in the case of a gable roof.
Sloping roofs in the lower tier can have a slope of up to 60 degrees, while the upper tier is usually more gentle. Most often, a sloping roof is used to build an attic. Permissible house width up to 10 m.
Such a roof is called a broken roof. Rafter systems can also vary in shape.
Various truss systems The shape of the truss system is determined by the dimensions of the structure and the purpose of the roof space. Struts, racks and rafters themselves can be used as decorative elements of the interior or attic.
decorative elements Types of truss systems
Among other things, rafter systems also differ in type. They are hanging and layered. The choice of the type of truss systems depends, like everything in the roof, on the dimensions of the structure to be covered and the position of the load-bearing walls.
Hanging rafter system
hanging rafters A system with hanging rafters is chosen if the building does not have internal load-bearing walls, and the span does not exceed 6 meters. In the upper part, the rafters rest on each other, and the Mauerlat acts as a support from below. Mauerlat is installed in a stone or brick house. In the case when the house is built using frame technology, the rafters are attached to the upper trim. In log cabins or beams - to the upper crown. The spread of the rafters is reduced by tightening. Beam puffs can serve as the ceiling of the upper floor.
The drawstring is located at the very bottom. If it is placed higher, then it is called a crossbar. In cases where the overlapped span is more than 6 meters, the system with hanging rafters is supplemented with support posts and braces. Filly is used to organize the overhang. Experts recommend building up the rafters with a mare, even if it is possible to organize an overhang due to the own length of the rafter leg. Such an extension will allow the rafters to be supported on the Mauerlat with the entire available cross-sectional area. And the section of the filly is chosen less than the section of the rafters.
Sloped truss systems
Rafters The main requirement for organizing a layered truss system is the presence of an internal load-bearing wall or columns in the building. A roof with rafters can cover spans from 10 to 16 meters. In this case, the slope is selected based on the weather conditions of the area. In the upper part, the rafters are supported by a ridge run, and in the lower part, by a Mauerlat. Parallel to the ridge run, a bed is arranged on which the racks rest. This allows you to do without puffs and crossbars. If the rafter leg does not have a brace or support, its length should not exceed 4.5 meters. The elements of the layered truss system must have a thickness of at least 5 cm.
Regardless of what type of truss system was designed, it is important:
- You cannot add nodes "from yourself" to the roof project. Even if it seems that it will be more reliable. The displacement of loads, the most insignificant at first glance, can lead to a distortion of the structure and possible collapse.
- Mauerlat must be aligned in a horizontal plane relative to the walls of the house. Next, they also strictly horizontally join it with the rafter leg. Vertical and horizontal levels are extremely important in order to avoid distortions.
- Rafter legs, racks and struts are placed strictly symmetrically.
- In order for the rafters not to rot, air vents are provided in the attics, and gaps in the attics.
- It is important to comply with the technology of insulation and vapor barrier of the roof.
- The joints of wooden elements with stone walls must be lined with waterproofing materials.
- When calculating the truss system, it is important to consider the location of the chimneys. This can affect the pitch width of the rafters.
Connecting elements
A system of fastening elements by cutting is allowed, but it should be remembered that this is not the most economical way. The cutting requires a rather large cross-sectional area so that the structure as a whole does not lose its strength. And this means that both the weight of the entire roof and the cost of building materials will be much higher. In this regard, most often the nodes are fastened with dowels and bolts.
Fastening Fasteners are often used with steel perforated plates. A huge number of such fasteners are on sale, various in shape and purpose. Perforated pads have a special coating that protects them from corrosion. Fasten them with nails.
truss system High demands are always placed on load-bearing parts. The main load-bearing elements are the walls, foundation and roof.
The roof frame plays a very important role. After all, it depends on him how long the roof will last.
The construction of the truss system very often causes difficulties for novice craftsmen. This article will help you make a roof frame with your own hands.
There are several types of truss system. The choice of one or another type depends on the purpose of the building, the nature of the coating and the type of roof.
The roof frame can be:
- Metallic. Such a truss system, as a rule, is designed in industrial construction. This is primarily due to high costs. Also, the construction of a metal frame implies large areas and volumes;
- wooden. This type of frame is used in the construction of residential buildings with pitched roofs. Is the most common type;
- From reinforced concrete slabs. They serve as a supporting base in the construction of a flat roof.
Before you start constructing a roof frame with your own hands, you need to decide on the type of truss system. To play the role of a support is the main purpose of any truss system.
Rafter legs or rafters are wooden beams with a section of 150 × 50 millimeters. From above, a crate is attached to them, and then - roofing material.
There are two types of roof frames: layered and hanging. They differ from each other in the way the rafters are connected. Both of these types are used in the construction of private houses. They differ in that a Mauerlat is used in a hanging rafter system - a longitudinal beam with a section of 100X100 mm.
The upper part should rest on the central load-bearing wall, and not be connected to each other.
The design and planning characteristics of the building under construction play an important role in choosing the type of truss system.
It is advisable to use a layered truss system if the distance between the supporting walls is too large. In this case, an “intermediate” wall is erected in the center of the building, which acts as an additional support. As a result, the rafters will not sag.
Otherwise, a hanging truss system is usually used. But if the roof frame is made of metal, then additional walls are not needed.
Mounting Features
When designing a truss system, the following points should be considered:
- If the climate in the area is humid, then it is better to choose a roofing material that has the best water resistance;
- The attic must be ventilated. If this is not done, then after a while the supporting structural elements will fail;
- The design must withstand not only the own weight of the roof with its elements. It must withstand a layer of snow, fallen leaves, and also withstand the pressure created by the wind;
Necessary materials and tools
When constructing a roof frame with your own hands, you will need:
- A hammer;
- Drill;
- Plane;
- Level;
- Saw;
- Self-tapping screws for wood;
- Roulette;
- Gloves;
- brackets;
- flame retardants;
- Staples;
- Antiseptics for wood;
- A bar with a section of 150 × 50 mm (for rafters);
- Studs 8 mm and 10 mm (for rafters);
- A bar with a section of 100 × 100 mm (for Mauerlat);
- Mounting studs (for Mauerlat);
- Reiki with a section of 40 × 40 mm (for crates).
Wooden structural elements must be treated with an antiseptic and fire retardant. This will extend the life of the structure, as well as reduce the risk of fire to a minimum.
Roof frame with two slopes
You need to start mounting the frame after:
- all tools are prepared;
- purchased the necessary materials;
- processed wooden elements with antiseptics and flame retardants.
Mauerlat laying is the initial stage in the construction of a gable roof frame. distributes and transfers the load from the rafters to the load-bearing walls.
It is important to note that wood can draw moisture out of the concrete base, after which it will crumble. In order to avoid this, it is necessary to lay roofing material under the bars in several layers.
The device of the truss system
Installation of the truss system includes the following steps:
- Determine the distance between the rafter legs. It is usually 80 - 90 centimeters. This distance corresponds to the dimensions of the crate;
- We make holes in the Mauerlat to fix the rafters;
- The construction of the roof frame usually begins with the gable of the building. It is necessary to install end rafters from both edges of the roof. After that, we stretch the cord between their skates. This cord will help line up the intermediate elements;
- We fix all the rafter legs on the Mauerlat with steel brackets and brackets. The protrusion of the rafters over the perimeter of the building should be approximately 40 centimeters.
- To fix the lower part of the rafters, you must use the strapping, which relies on the Mauerlat. If the rafter is not long enough, then it needs to be increased. To do this, put another beam on the rafter with an overlap of at least 100 centimeters. Such a large overlap is needed so that the roof does not lose its rigidity;
- It is necessary to install additional puffs between the rafter legs if the roof frame has a six-meter span. They are fixed between the supporting rafters;
- After the installation of all the rafters has been completed, we proceed to fix the rafters in a strictly vertical position. For these purposes, a ridge beam is used. It is attached to the top of the roof frame;
- When using soft roofing materials, you need to make a continuous crate. To do this, use moisture-resistant plywood or OSB - plates. If the roof is made of metal tiles, slate, corrugated board, then the crate should be thinned out. To increase the strength of the roof, regardless of the roofing material used, a continuous crate is made near the ridge part.
Features of the construction of the roof frame
The construction of the roof is an important stage in the entire construction of the house. That is why special attention is paid to the arrangement of the frame of the upper part of the building. To build a roof frame on your own, you need certain knowledge and experience. Next, we will talk about how to make a roof frame.
Depending on the type of roof structure, the roof frame has several types:
- Rafter frame structure, the basis of which are wooden elements. It is used in private construction for the construction of pitched roofs.
- Metal carcass. It is made of profile metal beams and is used mainly in industrial construction.
- Concrete frame. In its device, concrete slabs are used, which create a sloping roof, mainly in high-rise buildings.
Before starting the construction of the frame structure of the building, it is necessary to decide on the choice of one of the above types and the frame of the truss system, in which the load-bearing capacity is completely transferred to the trusses. For the installation of a truss truss, a timber beam is used, which in cross section should be at least 15.0 × 5.0 cm in size. After attaching the rafters to the building and to each other, the roofing system of the crate is fixed to the frame.
The truss structure is divided into layered and hanging. It is selected depending on the design features of the building. Both types of rafters are used in the construction of private houses and differ in that, with a hanging system, the main beams are supported by a mauerlat, which is arranged along the perimeter of the building and attached to the surface of the bearing walls on the top row of masonry. In practice, the Mauerlat is a wooden beam with a cross section of 10.0 × 10.0 cm. The rafter legs on the upper side of the truss are fixed to each other using a ridge beam. The layered structure in the upper part is not fastened with rafters to each other. Such a wooden frame is made in a different way.
With a layered system, trusses at the top of their structure abut against a longitudinal central wall or specially provided columns for supports.
When choosing the type of truss structure, the overall dimensions of the structure are of great importance.
Note! Hanging rafters are used in the construction of roofs for houses, the distance between the external load-bearing walls of which does not exceed 6.0 m. If the span is greater than this value and there is a longitudinal central wall with load-bearing characteristics or supporting columns, then a layered truss frame is used. In this case, it will not be affected by the increased load from the weight of the roofing material.
You need to know that the Mauerlat is the main support for the frame structure and the roofing material of the roof. The task of the Mauerlat is to take loads from the entire roof structure and distribute them evenly to the load-bearing walls of the building.
- Thanks to this structural element, the durability of not only the roof, but the entire building as a whole increases. If this tier of timber had not been used, the vertical loads from the roof would have acted with a destructive force on the load-bearing walls at certain points. In fact, the mauerlat performs the main supporting and protective function in the entire frame structure of the top of the structure. Such a support is not needed only in the construction of wooden houses, in which the top of the walls ends with the laying of beams or logs. This important structural element must be installed when constructing the roof frame in such a way that its internal surfaces and the bearing walls are in the same plane. This will make the interior decoration of the house more convenient.
- From the side of the street, the Mauerlat must be buried with brickwork so that the wood material is not exposed to natural phenomena. Walls made of blocks or bricks must be leveled at the top with a concrete screed. She, in turn, should be covered with roofing material in several layers. Instead of this material, heated bitumen can be used. Insulating material is used to protect the Mauerlat from moisture that could be transferred to it from the walls. Excess moisture has a detrimental effect on wood material and reduces its durability.
- The most practical and reliable method of fixing the Mauerlat to the walls of the building is the use of metal studs that firmly fasten the surfaces of both elements. Holes of the required size are made in bricks or blocks. Finished metal studs, which are made from steel reinforcement, are inserted into the drilled holes. Then the beam for the support is applied to the studs for fitting, marks are made and holes are also made along them in the Mauerlat.
Note! When installing, pay attention to the length of the studs. They should protrude from the body of the support beam at a distance of 1.5 cm. Threads should be cut at the ends of the metal parts, which is ultimately used to finally fix the Mauerlat with large diameter washers and nuts. As an alternative to such fastening, welding can be used.
Installation of the truss frame
At the next stage of work, the frame of the roof truss structure is being installed. Before installing roof trusses, you need to purchase dry wooden elements so that they do not deform or warp over the next time.
- During construction, the truss structure should include rafter legs in the amount of 2 pieces and ties to connect the first in their lower part. The ties are fixed to the rafter legs with anchor parts and bolts. Roof trusses in the required quantity are attached to the Mauerlat and fixed using simple technologies. They consist in making the required number of cuts of the correct shape in the support beam. Rafters are installed in these grooves with the help of simple manipulations. The distance between the truss structures depends on the exact dimensions of the roof, which are based on the dimensions of the house. In practice, the rafters should be spaced at a distance of up to 1 m from each other. It must be taken into account that rafters with a vertical direction are used in some roof frames. Such structural elements are used for high roofs with a vertical dimension of 3 m or more.
- The crate wooden system perfectly connects the structural elements of the frame. But before it has not yet been installed, it is necessary to ensure the stability of the roof trusses. For this purpose, a ridge-type beam is foreseen at the top of the structure. On the lower side, a temporary strapping is organized, which is removed after the installation of the planks or boards of the crate. As you can see, the crate plays an important role not only for the installation of roofing material, but also for the reliable bonding of all structural elements when the roof frame is made by hand.
- The crate system can be divided according to its type into intermediate and continuous. The choice of type of lathing depends on what kind of roofing material the roof will be covered with. An intermediate crate is used if the roof is covered with dense sheet materials. In this case, there must be a certain distance between the slats.
- If the roofing of the roof is expected to be soft or it is rolled up, then a solid crate is used. Only on such a surface can this type of roofing material be laid with high quality, and only in this way can the long operation of the roof be ensured. Soft tiles will feel good on a solid crate. If this material is laid on an intermediate system, then it will hang down and be operated poorly.
For example, for a galvanized sheet, metal tile or slate, an intermediate type crate is well suited. But since these materials require fastening in certain places, the battens must be mounted with a certain step. Therefore, for the correct construction of the roof frame, preliminary calculations must be made.
Note! Any wood materials are susceptible to fungus and insects, and they also burn. To protect the wooden material from pests, the bars and boards must be protected with antiseptic impregnations. In order for a tree to lose its ability to burn, it must be treated with fire retardants. Processing of all wooden elements should be carried out even before the start of installation work. This will increase the durability of the wooden roof frame.
In industrial construction, as well as in the construction of multi-apartment high-rise buildings, roof frames are not made of wooden elements. Rafter systems are made of profile metal. The light metal frame of the roof, which consists of steel of various profiles with thin walls, is reliable and has a long service life. If we compare metal rafters and wooden rafters, then the former have a number of advantages.
- Metal elements, unlike wooden ones, do not burn. In the event of a roof fire, metal structures are able to withstand high temperatures for a long time and not allow the roof to collapse.
- When using metal rafters, there is no need to treat structural elements with antiseptics and flame retardants.
- Since the structure is not subject to infection by insects and fungus, and the surface of the elements is coated with zinc, which prevents corrosion, such a roof can be used for about 100 years.
- Metal rafters can be mounted in all weather conditions.
- It should be noted the ease of installation of rafters. Installation requires a minimum of tools.
- Since the structure has a small mass, it does not exert large loads on the load-bearing walls of the structure.
Since metal rafters are not afraid of heavy loads, any roofing material can be used as a roof covering.
A photo
Video
In this video we are talking about the installation of the roof truss system.