How to build a roof frame. Types and diagrams of rafter systems: overview and recommendations for installing a roof rafter system
When designing any residential building, architects Special attention pay attention to the roof, since it performs not one, but several functions at once, depending on its design features. It must be said that not all future homeowners are satisfied with an ordinary gable roof, although it can be called the most reliable, since it has only two pitched planes and one joint between them. Many people are more attracted to complex designs, which add special attractiveness and originality to the building. Other, more practical homeowners prefer attic structures, which can simultaneously serve as a roof and a second floor.
The basis of any roof is an individual rafter system, which has its own design features. It will be much easier to choose the right roof frame if you figure out which ones in advance. types and diagrams of rafter systems used in construction practice. After receiving such information, it will become more clear how difficult such structures are to install. This is especially important to know if you plan to build the roof frame yourself.
Main functional tasks of rafter systems
When settling in pitched structures roofs, the rafter system is a frame for covering and holding the materials of the “roofing cake”. With proper installation of the frame structure, the necessary conditions for correct and non-insulated types of roofs that protect the walls and interior of the house from various atmospheric influences.
Roof structure is also always the final architectural element of the exterior design of a building, supporting it with its appearance stylistic direction. However, the design features of rafter systems must first of all meet the strength and reliability requirements that the roof must meet, and only then the aesthetic criteria.
Frame rafter system shapes the configuration and angle of the roof. These parameters largely depend on natural factors characteristic of a particular region, as well as on the desires and capabilities of the homeowner:
- Amount of precipitation in different periods of the year.
- Direction and average speed winds in the area where the building will be erected.
- Plans for the use of space under the roof - arranging residential or non-residential premises, or using it only as an air gap for thermal insulation of the rooms below.
- Type of planned material roofing.
- Financial capabilities of the homeowner.
Atmospheric precipitation and the strength of wind currents place a very sensitive load on the roof structure. For example, in regions with heavy snowfall, you should not choose a rafter system with a small slope angle, since snow masses will linger on their surface, which can lead to deformation of the frame or roofing or to leaks.
If the area where the construction will take place is famous for its winds, then it is better to choose a structure with a slight slope of the slope so that sudden gusts that occur do not tear off individual elements of the roof and roofing.
Main elements of roof structure
Parts and components of rafter systems
Depending on the type of rafter system chosen, the structural elements used can vary significantly, however, there are parts that are present in both simple and complex roof systems.
The main elements of a pitched roof rafter system include:
- Rafter legs, forming the roof slopes.
- - a wooden beam fixed to the walls of the house and used to fix the lower part of the rafter legs on it.
- A ridge is the junction of the frames of two slopes. It is usually the highest horizontal line of the roof and serves as the support to which the rafters are anchored. The ridge can be formed by rafters fastened together at a certain angle or fixed on a ridge board (purlin).
- Sheathing is slats or beams mounted on rafters with a certain pitch and serving as the basis for the flooring of the selected roofing material.
- Supporting elements, which include beams, purlins, racks, struts, ties and other parts, serve to increase the rigidity of the rafter legs, support the ridge, and connect individual parts into an overall structure.
In addition to the mentioned design details, it may also include other elements, the functions of which are aimed at strengthening the system and optimally distributing roof loads on the walls of the building.
The rafter system is divided into several categories depending on different features of its design.
Attic space
Before we look at different types roofs, it’s worth figuring out what it could be like attic space, since many owners successfully use it as utility and full-fledged residential premises.
The design of pitched roofs can be divided into attics and attics. The first option is called this way because the space under the roof has a small height and is used only as an air layer insulating the building on top. Such systems usually include or have several slopes, but located at a very slight angle.
An attic structure that has a sufficiently high ridge height can be used in different ways, be insulated and not insulated. Such options include an attic or gable option. If you choose a roof with a high ridge, then it is imperative to take into account the wind loads in the region where the house is built.
Slope slope
To determine optimal inclination roof slopes of a future residential building, first of all you need to take a closer look at the already built low-rise neighboring houses. If they have been standing for more than one year and can withstand wind loads, then their design can safely be taken as a basis. In the same case, when the owners set a goal to create an exclusive original project, unlike the nearby buildings, it is necessary to familiarize yourself with the structural and operational features various rafter systems and make the appropriate calculations.
It should be taken into account that the change in tangential and normal values of wind force depends on how large the slope of the roof slopes is - the steeper the slope angle, the higher value have normal forces and less tangent forces. If the roof is flat, then the structure is more affected by the tangential wind load, since the lifting force increases on the leeward side and decreases on the windward side.
Winter snow load should also be taken into account when designing the roof. Usually this factor is considered in conjunction with the wind load, since on the windward side the snow load will be much lower than on the leeward slope. In addition, there are places on the slopes where snow will certainly accumulate, putting a large load on this area, so it should be reinforced with additional rafters.
The slope of roof slopes can vary from 10 to 60 degrees, and it must be selected not only taking into account the consolidated external load, but also depending on the roofing covering that is planned to be used. This factor is taken into account because roofing materials differ in their mass; to secure them, it is required different quantity elements of the rafter system, which means the load on the walls of the house will vary, and how large it will be also depends on the angle of the roof. The characteristics of each coating in terms of resistance to moisture penetration are also important - many roofing materials in any case require one or another slope to ensure free descent storm water or melting snow. In addition, when choosing a roof slope, you need to think in advance about how the cleaning process will be carried out and repair work on the roof.
When planning a particular angle of the roof slopes, you need to know that the fewer joints between the sheets of roofing, and the more airtight they are, the less you can make the slope of the slope, of course, if you are not planning to arrange a residential or utility room in the attic space.
If a material consisting of small elements is used to cover the roof, for example, ceramic tiles, then the slope of the slopes must be made steep enough so that water never lingers on the surface.
Considering the weight of the roofing material, you need to know that the heavier the covering, the larger the angle of the slopes should be, since in this case the load will be correctly distributed over the rafter system and load-bearing walls.
Can be used to cover the roof following materials: or profile sheet, galvanized steel, corrugated asbestos concrete and bitumen-fiber sheets, cement and ceramic tiles, roofing felt, soft roofing and other roofing materials. The illustration below shows the permissible slope angles for various types roofing coverings.
Basic designs of rafter systems
First of all, it is worth considering basic types rafter systems relative to the location of the walls of the house, which are used in all roof structures. Basic options They are divided into layered, hanging, and also combined, that is, including elements of both the first and second types of systems in their design.
fastenings for rafters
Layered system
In buildings where internal load-bearing walls are provided, a layered rafter system is often installed. It is much easier to install than a hanging one, since the internal load-bearing walls provide for its elements reliable support, and in addition, this design will require less materials.
For rafters in this system, the defining reference point is the ridge board, on which they are fixed. The non-thrust type of layered system can be arranged in three options:
- In the first option, the upper side of the rafters is fixed on a ridge support, called a sliding one, and their lower side is fixed by cutting to the mauerlat. Additionally, the rafters in the lower part are fixed to the wall using wire or staples.
- In the second case, the rafters in the upper part are cut at a certain angle and connected to each other using special metal plates.
The lower edge of the rafter legs is attached to the Mauerlat with movable fasteners.
- In the third option, the rafters are rigidly fastened in the upper part with bars or treated boards located horizontally, parallel to each other on both sides of the rafters connected at an angle, and between them the ridge run.
In the lower part, sliding fasteners are used to secure the rafters, just as in the previous case.
It is necessary to explain why sliding fasteners are often used to secure rafters to the mauerlat. The fact is that they are able to relieve load-bearing walls from excessive stress, since the rafters are not rigidly fixed, and when the structure shrinks, they have the ability to move without deforming general design roofing system.
This type of fastening is used only in layered systems, which also distinguishes them from the hanging version.
However, in some cases, for layered rafters, a spacer system is used, in which the lower end of the rafters is rigidly fixed to the Mauerlat, and to relieve the load from the walls, tie-downs and struts are built into the structure. This option is called complex, as it includes elements of a layered and hanging system.
According to statistics, every second homeowner built his own home. According to their reviews, self-construction Roofs are one of the most difficult stages for non-professional builders. Therefore, it is very important to approach this stage with a complete understanding of all the nuances of the process. To understand how to make a roof with your own hands, you need to study the device, installation technology, work order and features of fastening all components of the structure.
Types of roofs
First you need to decide on the form. To date, the most popular types are:
Features of formsCovering the roof with one single slope will save nerves and materials, since structurally this is the simplest option. If you make such a frame yourself, the labor intensity of the work will be minimal and the installation speed will be high. But this form has a drawback - there is no possibility of arranging a full-fledged attic or attic, since the under-roof space is too low.
A gable roof is installed much more often. It is a little more difficult to manufacture, but allows you to get more space. Compared to the hipped one, it has less complexity and mass, but it will be necessary to make triangular pediments at the ends of the building.
Gable - the most popular form Before you begin to independently construct a roof with four slopes, you will need to seriously prepare. This system has more elements compared to the previous two. In addition, it is not possible to make full-fledged windows in the attic, since the roof structure does not have gables and installation is difficult or cannot be avoided.
The hipped roof is complex in design, but savings are achieved due to the absence of gables For the attic excellent option there will be a combined design with . In this case, in the lower part the roof has a greater slope than in the upper section. This assembly allows you to raise the ceiling in the room and make the constructed house more comfortable.
Broken line - not the most “architectural”, but very effective in terms of space used Calculation
Before starting work, you need to make a design calculation. It makes no sense to calculate the cross sections of all elements. In most cases they can be accepted constructively:
- Mauerlat - 150x150 mm;
- racks - 100x150 or 100x100 mm depending on the cross-section of the rafters;
- struts - 100x150 or 50x150 mm, taking into account ease of connection with the rafters;
- puffs - 50x150 mm on both sides;
- purlins - 100x150 or 150x50 mm;
- overlays with thickness from 32 to 50 mm.
Calculations are usually performed only for rafter and slope legs. It is necessary to select the height and width of the section. The parameters depend on:
- roofing material;
- snow area;
- pitch of rafters (selected so that it is convenient to lay insulation, for mineral wool there should be 58 cm of clearance between the elements);
- span.
You can select the cross-section of the rafters using general recommendations. But in this case it is recommended to make a small reserve.
The calculation is usually performed for rafter legs If you don’t want to delve into the intricacies of calculations, you can use special ones.
If you are planning to do warm roof, then the height of the cross-section of the legs is selected taking into account the thickness of the insulation. It must be mounted so that it does not protrude higher load-bearing beams. You also need to take into account that for mineral wool a ventilation gap of 2-4 cm is made between it and the coating. If the height of the rafters is not enough for this, provision is made for installing a counter-lattice (counter battens).
Step-by-step instructions for performing the work
The sequence of stages of roof construction is as follows:
- taking measurements of the building box (dimensions may slightly differ from the design ones);
- preparation of materials and tools, treatment of wood with antiseptic;
- fastening the Mauerlat to the wall;
- installation of a ridge crossbar, if needed (for layered rafters);
- frame installation;
- strengthening the roof using racks, struts and tie-downs;
- waterproofing;
- sheathing;
- providing ventilation;
- installation of drips;
- installation of coating.
Fastening the Mauerlat
In order for the roof to be securely fastened, you need to take care of it reliable connection with the wall of the building. If a wooden house is being built, then the Mauerlat is not required - this element is the upper crown made of timber or logs. In this case, fastening to the wall is carried out using special “floating” fasteners. They are sold ready-made, most often called sleds. This type of roof arrangement allows the entire structure to shift slightly as the walls shrink without destruction or deformation.
“Sliding” fastening in a wooden house
A similar situation arises with a frame house. In this case, the Mauerlat will be the top frame of the walls. It is attached to the frame posts with a gash using angles, staples or nails.
Methods for attaching rafters to the frame in frame house The roof structure made of brick, concrete blocks or concrete involves fastening through a Mauerlat. In this case, there are several ways.
There are four ways to place the Mauerlat on the wall:
- on staples;
- on stiletto heels;
- on anchor bolts.
The Mauerlat can be secured to brackets. In this case, they are laid in the masonry from the inside wooden blocks. They should be located at a distance of 4 rows from the edge. One side of the bracket is attached to the mauerlat, and the other to the same block in the masonry. The method can also be considered simple. It is not recommended for large buildings with high loads.
Fastening the Mauerlat to brackets. Antiseptic wooden blocks are provided in the masonry of the wall with a pitch of 1-1.5 m When installing the roof yourself, fastening can be done through studs or anchor bolts with a diameter of 10-12 mm. The fasteners are laid in the masonry. The Mauerlat is temporarily placed on the sawn-off edge and lightly hit with a hammer. After this, indentations remain on the beam at the fastening points. You need to make holes for the studs along them. After this, the beam is put on the fasteners and the nuts are tightened. The method is ideal for walls made of lightweight concrete if available monolithic armored belt.
Fastening the rafters to the mauerlat
In houses made of brick or stone, it is more reasonable to perform it using rigid fastening of the rafters to the mauerlat. In this case, you can use both a layered and hanging system. The design involves two methods:
- with notch;
- without cutting.
In the first case, the rafters are cut with a slope so that they are tightly adjacent to the mauerlat. To remove the cornice, fillies are provided. They are attached to the leg with an overlap of at least 1 m. Rigid fixation of the assembly should be done using self-tapping screws, nails or staples. But more reliable assembled frame will work if you use metal corners with holes for self-tapping screws for fixation.
The method without cutting often does not involve the use of fillies. In this case, the beams themselves provide the frame extension. This option is simpler than the previous one, since it does not require high precision. It is suitable for beginners. In this case, stop bars or boards are used to ensure a tight fit to the Mauerlat. Rigid fixation, as in the previous case, is performed metal corners on both sides.
Attaching rafters to the wall
The completed frame must be secured to the frame of the building - this will prevent a strong gust of wind from tearing off the roof. To do this, the rule is to use a twist of two wires with a diameter of 4 mm. They are wrapped around the leg where it rests on the mauerlat, and then the wire is attached to the wall with an anchor or ruff about 4-5 rows before the cut. The element must be laid in the masonry in advance.
Wind protection For wooden house you can simplify the task. You can assemble the frame using staples. This option will speed up the process. But it is important to remember that this method is only suitable if the walls are made of wood.
Strengthening the system
How to strengthen the frame for spans of more than 6 meters? It is necessary to reduce the free span of the rafters. For this purpose, struts and racks are used. Reinforcement must be done taking into account the layout; it is important that these elements do not interfere with people’s stay and fit harmoniously into the interior.
The struts are usually placed at an angle of 45 or 60 degrees to the horizontal plane. The racks cannot be supported on the floor span. They can be installed on underlying walls or beams and trusses thrown between walls.
Tightening is necessary to reduce the thrust. Because of it, the rafters can simply move apart. This is especially true for systems with hanging beams. To assemble the frame, use two ties, which are attached on both sides of the rafters. Fixation is carried out using screws, nails or studs.
At the top point, the rafters rest on an intermediate or ridge girder. Depending on the chosen system, location and width of the span, it is made of timber with a cross-section from 50x100 to 100x200 mm. Fastening is carried out on connecting metal plates, bolts or nails.
Lathing
Before starting work at this stage, it is necessary to lay waterproofing material. Builders recommend using a vapor diffusion moisture-proof membrane. It costs more than polyethylene film, but guarantees more reliable protection. Owning your own home is not a reason to save money.
The roof requires fastening of the sheathing. The type depends on the selected roofing material. For metal, a sparse sheathing of boards 32-40 mm thick will be sufficient. Under bitumen shingles you need a continuous sheathing made of 25-32 mm boards or moisture-resistant plywood.
Ventilation of the under-roof space
Before proceeding with the roofing stage, it is worth considering the ventilation of the under-roof space. This will protect structures from mold, mildew and destruction.
Proper ventilation under the roof will protect the structure from the appearance of fungus For ventilation it is necessary to provide:
- air flow through the cornice (the cornice is hemmed with a sparse board or special perforated soffits);
- air movement under the coating (there should be a gap of 2-3 cm between the insulation and the roof);
- air outlet in the area of the ridge (for this, a ridge and/or point aerator is installed on the roof).
Roof covering
The type of roof is selected for aesthetic and economic reasons. It is also worth studying manufacturers' offers and finding out permissible slope. For example, it is not recommended to lay bitumen shingles on a slope of more than 45°.
Seam roofing is a lightweight fireproof and durable covering The flooring material must provide reliable waterproofing. Its installation is carried out in strict accordance with the manufacturer's instructions. There are five most common types of coverage: roof insulation.
Filimonov Evgeniy
Reading time: 8 minutes
A A
How to build a roof frame house, choice of material. Staged work, roof insulation. Roof installation technology, types of frame house roofs.
The roof of a frame house has great importance under construction. After all, protection from external conditions aggressive environment.
This article highlights the design features of the roof. What you need to do before you take on the roof installation job. What types of roofs frame houses, the required slope of the slopes. How to choose the right material for a reliable roof, the correct installation of rafters: pitch, length, section. Competent creation of sheathing and counter-lattice. How to install the roof of a frame house.
What you need to decide before building the roof. How to choose the right roof configuration. Required number of slopes. The correct installation of the crossbar, how to connect the rafters in the ridge. Correct fastening of the rafters to the mauerlat and fastening of the crossbar to the rafters.
What is the essence of the structure of the roof and roof of a frame house. How to build a gable roof on a frame house. Hip roof construction technology. How to perform competent installation of an attic (broken) roof of a frame house.
Advantages of frame houses and roof insulation, hanging layer system technology.
The roof structure of a frame house is one of the simplest, so its independent construction will not take much effort and time.
This article will help you if difficulties arise during the work. In it we will look at the features of roof installation, give practical recommendations on the choice of material, structural elements, and compliance necessary standards and requirements during the work process.
Before starting construction, you need to decide:
- With roof type and slope angle
- Type of roofing material
- Length, cross-section of rafters and distance between them
- Length, pitch and cross-section of sheathing and counter-lattice elements
- Type of insulation
Type of roofs of frame houses
Roofs are:
- Flat
- Pitched (with one, two or more slopes)
- Attic (with two and four slopes)
- Pincer, conical, multi-pinion, etc.
The choice of roof is made not only based on the conditions of its appearance. Important to consider functionality designs. Main advantages and disadvantages of roofs different types are given below.
Frame house with flat roof
Flat roofs are not popular in private construction. Their construction does not cause difficulties, but the shortcomings cover everything. They require careful care. After rain, water remains on the roofs, and in winter you have to remove the snow yourself. This increases the likelihood of moisture penetrating into the room. On houses with pitched roof You can use the attic as an additional room.
But during installation flat roof You can save a lot on building materials and sunbathe on it in the summer.
During installation, it is necessary to maintain a slope angle of 2-3 degrees relative to the horizon.
Multi-slope and pitched roof frame house
The slope angle of the slopes starts from 10 degrees. The number of slopes is from 1 to 4.
Pitched roofs are very popular and are used everywhere. In spring, snow does not stay on them for a long time, water calmly flows down the gutters, and a lot of additional space appears in the form of attic space, where you can arrange an additional room.
The load on the structure is also reduced, and with it the possibility of leaks.
Mansard roof
It can be semi-hip (double slope with two small slopes) and hip (four slope). This type of roof is also widely used.
The advantages are as follows: extra bed under the roof, possibility of installing windows, unique appearance at home, low load on the structure in winter. Disadvantages - high costs for materials, heating, a lot of snow on window structures in winter, faster destruction truss structures due to insufficient ventilation.
Multi-gable roof
The multi-gable roof is considered one of the most popular. It differs from others in the large number of slopes and the presence of valleys. Installed if the house has a complex layout.
Advantages - the design can withstand significant loads, it becomes possible to equip an additional room, and a unique appearance. Disadvantages: high consumption of material, leaving a lot of waste, difficulty in DIY installation, and high financial costs.
Conical roofs
A conical roof is installed when the building is made in the shape of a circle. In Russia, few people build such roofs.
Advantages: interesting appearance, ease of maintenance. Disadvantages: complexity of calculations and installation.
We suggest choosing a roof with two slopes. In this case, it will be possible to significantly reduce the cost of materials and maintenance, while the appearance of the structure will not be affected.
It is worth understanding that the more slopes, the more beautiful the roof, but also more expensive. But if you are not used to saving and want the best, then install a roof of any type.
The roof structure of a frame house is one of the simplest, so its independent construction will not take much effort and time.
This article will help you if difficulties arise during the work. In it, we will consider the features of roof installation, give practical recommendations on the choice of material, structural elements, and compliance with the necessary standards and requirements during the work process.
What to do before starting work?
Before starting construction, you need to decide:
- With roof type and slope angle
- Type of roofing material
- Length, cross-section of rafters and distance between them
- Length, pitch and cross-section of sheathing and counter-lattice elements
- Type of insulation
Type of roofs of frame houses
Roofs are:
- Flat
- Pitched (with one, two or more slopes)
- Attic (with two and four slopes)
- Pincer, conical, multi-pinion, etc.
The choice of roof is made not only based on the conditions of its appearance. It is important to consider the functionality of the design. The main advantages and disadvantages of different types of roofs are given below.
Frame house with flat roof
Flat roofs are not popular in private construction. Their construction does not cause difficulties, but the shortcomings cover everything. They require careful care. After rain, water remains on the roofs, and in winter you have to remove the snow yourself. This increases the likelihood of moisture penetrating into the room. On houses with a pitched roof, you can use the attic as an additional room.
But when installing a flat roof, you can significantly save on building materials and sunbathe on it in the summer.
During installation, it is necessary to maintain a slope angle of 2-3 degrees relative to the horizon.
Multi-pitched and single-pitched roof of a frame house
The slope angle of the slopes starts from 10 degrees. The number of slopes is from 1 to 4.
Pitched roofs are very popular and are used everywhere. In the spring, snow does not linger on them for a long time, water calmly flows down the gutters, and a lot of additional space appears in the form of an attic space, where you can arrange an additional room. The load on the structure is also reduced, and with it the possibility of leaks.
Mansard roof
It can be semi-hip (double slope with two small slopes) and hip (four slope). This type of roof is also widely used.
The advantages are as follows: additional space under the roof, the ability to install windows, a unique appearance of the house, low load on the structure in winter. Disadvantages - high costs for materials, heating, a lot of snow on window structures in winter, faster destruction of rafter structures due to insufficient ventilation.
Multi-gable roof
The multi-gable roof is considered one of the most popular. It differs from others in the large number of slopes and the presence of valleys. Installed if the house has a complex layout.
Advantages - the design can withstand significant loads, it becomes possible to equip an additional room, and a unique appearance. Disadvantages: high consumption of material, leaving a lot of waste, difficulty in DIY installation, and high financial costs.
Conical roofs
A conical roof is installed when the building is made in the shape of a circle. In Russia, few people build such roofs.
Advantages: interesting appearance, ease of maintenance. Disadvantages: complexity of calculations and installation.
We suggest choosing a roof with two slopes. In this case, it will be possible to significantly reduce the cost of materials and maintenance, while the appearance of the structure will not be affected.
It is worth understanding that the more slopes, the more beautiful the roof, but also more expensive. But if you are not used to saving and want the best, then install a roof of any type.
Slope slope
The ideal slope for safety and durability is a slope of 30 to 45 degrees. In this case, the load on the roof (wind, snow) is optimal.
At the same time, externally, a roof with such a slope looks more advantageous.
Choosing roofing material
The choice of roofing material depends on the slope of the slopes. In this case, the necessary requirements safety and increased roof service life.
Below are the main types of roofing materials and the slope angle that must be observed during installation:
- Corrugated sheeting – from 10 degrees
- Slate - from 12 to 60 degrees
- Euroslate (ondulin)– from 6 degrees and above
- Ceramic tiles– 18-60 degrees
- Polymer sand tiles– 18-60 degrees
- Bituminous shingles– from 12 degrees without limiting the maximum slope
- Metal tiles– from 15 degrees
When choosing the type of roofing material, you must follow the following recommendations:
- The material must match the roof configuration
- The service life of the material should be as close as possible to the shelf life of the roof itself
- The selected material must meet the aesthetic and economic criteria of the owner. It is necessary to take into account the complexity of the masonry and the cost of the roofing material, the complexity of the roof layout, etc.
- The roofing material must have the most “advantageous” characteristics: durability, resistance to mechanical and climatic influences, ease of maintenance, frost resistance, level of sound insulation, climatic conditions, etc. If you live where it hails frequently, you shouldn't choose a roofing material that will turn into rags after the first rainfall.
Rafters: section, pitch, length
To calculate rafters, you can use a special calculator, saving time: 
The cross-section of the rafters is selected taking into account the following parameters:
- Lengths of rafter legs and pitch of their installation
- Roof slope (the smaller it is, the less load on the surface)
- Loads (snow, wind, etc.) that are set in regulatory documents for each region of the country
- The type of material that will cover the roof, as well as its weight and size
You can select a section in two ways: refer to construction tables or carry out your own calculation.
We suggest that you familiarize yourself with the standards given in the table below. However, it is always better to choose the option with a reserve. From the table you can immediately select the rafter pitch and length.
| Rafter installation pitch, mm | Length of individual rafters, m | ||||||
| 3,0 | 3,5 | 4,0 | 4,5 | 5,0 | 5,5 | 6,0 | |
| 600 | 40x150 | 40x175 | 50x150 | 50x150 | 50x175 | 50x200 | 50x200 |
| 900 | 50x150 | 50x175 | 50x200 | 75x175 | 75x175 | 75x200 | 75x200 |
| 1100 | 75x125 | 75x150 | 75x175 | 75x175 | 75x200 | 75x200 | 100x200 |
| 1400 | 75x150 | 75x175 | 75x200 | 75x200 | 75x200 | 100x200 | 100x200 |
| 1750 | 75x150 | 75x200 | 75x200 | 100x200 | 100x200 | 100x250 | 100x250 |
| 2150 | 100x150 | 100x175 | 100x200 | 100x200 | 100x250 | 100x250 | _ |
Lathing
Depending on the slope of the roof and the roofing material (in this case, tiles were chosen), you can select the pitch and dimensions of the sheathing according to the table.
The cross-section of the step lathing bars can be selected as 50 by 40 mm.
| Roof slope, degrees | Lathing pitch, mm | Consumption of tiles, pcs/m2 |
| 50 | 375 | 8,9 |
| 45 | 370 | 9,0 |
| 45 | 365 | 9,2 |
| 40 | 360 | 9,3 |
| 35 | 355 | 9,4 |
| 35 | 350 | 9,6 |
| 30 | 345 | 9,7 |
| 25 | 340 | 9,8 |
| 20 | 335 | 10,0 |
| 15 | 330 | 10,1 |
| 14 | 320 | 10,4 |
Counter-lattice
The size and cross-section of the counter-lattice can be made the same as that of the sheathing.
The pitch should match the pitch of the rafters.
Installation of the roof of a frame house
Installation sequence for gable roof as follows:
- Installation of the rafter system
- Laying insulation
- Arrangement of lathing and counter-lattice
- Installation of roofing material and finishing structural elements
Installation of the rafter system
Installation of rafter legs begins after they are securely fixed ceiling beams(mauerlats). The rafters will be a beam with a cross section of 50×150 mm, or 50×200 mm. Take a more accurate cross-section from the table above.
Preparing the rafters
First you need to make a template for the rafter legs. This is done like this:
- Take two boards and overlap them at an angle of 90 degrees, fixing them with a nail at the top point
- The template is lifted up and the edges of the boards are installed on the mauerlats
- By adjusting the arrangement of the boards, the desired slope is found. At the same time, their edges should extend 40-60 centimeters beyond the level of the walls, to make it easier to install a drainage system in the future. If the length of the boards is not enough, you can sew two on the ground
- When the required slope of the slopes is obtained, it is necessary to nail a crossbar between the rafter legs, thereby fixing the angle. At the same time, you need to mark with a pencil the cut line of the rafters if they will be fixed end-to-end and cuts at right angles in the places where the legs are attached to the mauerlats
- All calculations must be made with maximum accuracy
After the template has been prepared, you need to use it to assemble two pairs of rafters, which will be mounted along the edges. If necessary, the legs are extended. They can be joined halfway across the tree using thick bolts, which is safer, or using two nails driven in at different angles. A cross member must be installed between the two legs of one rafter.
Timber splicing
Overlapping rafter connection
Splicing rafters using the butt joint method
Twin rafters
Rigid connection with a steel angle and a supporting sheathing beam
Driving nails from the sides, at an angle towards each other
Sliding connection of rafters
The next step is to lift the rafters onto the roof and fix them on the mauerlats (beams), as shown in the picture. A thrust block is mounted below.
When two pairs of side rafters are installed, you need to stretch the rope between them. It serves as a beacon by which the level is checked. Next, the distance between the rafters is measured and divided by 60 or 80, depending on the step with which the installation will be carried out.
After the calculations are carried out, it is collected on the ground required quantity rafters Then they rise to the top and are installed with the selected step along the entire perimeter. Two boards are nailed between the trusses for fixation.
Insulation of the roof of a frame house
To avoid freezing in winter, you need to insulate the roof.
First to inside rafter legs using construction stapler a vapor barrier film is attached. The joints are being worked out double-sided tape. Then insulation boards are laid in the space between the rafter beams.
To protect the insulation from precipitation, you need to lay it on top diffusion membrane. If you plan to use reinforced film, then leave a gap of 2 centimeters between it and the insulation.
Here's a great photo that makes the process easier:
- 1 - Rafter
- 2 - Insulation
- 3 - Under-roof wind-water insulation
- 4 - counter rail
- 5 - Lathing
- 6 - Roof covering
Lathing and counter-lattice
The counter-lattice can be made with bars 25 by 30 centimeters or 30 by 50. The spacing of the bars is the same as that of the rafters, since they are mounted on top of them. This is clearly visible in the photo above.
The sheathing is mounted on the counter-batten. For this, boards 25 by 100 mm, or beams 40 by 50 mm are used. The sheathing pitch depends on the type of roofing that will be used. Fastenings are made with galvanized nails, the length of which is three times the thickness of the bars or boards and in a checkerboard pattern.
In the photo below, select the desired distance for your option.
Installation of roofing material
In our case, we will consider the installation of metal tiles. It starts from bottom to top.
First, the cornice strip is installed using self-tapping screws. Next, the first sheet of metal tiles is lifted onto the roof. TO cornice strip it is attached with self-tapping screws into each recess. Then you can attach the sheet through one notch. If the length of one sheet of tile is not enough, you can extend it using free pieces, laying them overlapping and fixing them with 4.8 x 28 mm self-tapping screws. Next, the remaining sheets are laid in a similar manner with an overlap.
The bottom edge of the tiles should protrude 40 cm beyond the edge of the eaves.
The main element of the roof structure is the frame, since it bears a large mechanical load. For this reason, increased demands are placed on it regarding reliability, strength and durability.
Even when using the highest quality building materials for roofing, if the roof frame is made in violation of technology, the constructed structure will quickly become unusable.
You can build the frame part of a small house yourself, but subject to correct calculations and skills construction work and appropriate theoretical training. As a result, you will be able to save a considerable amount. If you still decide to use the services of professional roofers, then the owner of the house will be able to keep control over the process of creating the frame.
The article describes the arrangement of the most common type of roof - gable. If the technology for constructing such a roof frame has been mastered, then other structures (for example, broken, hipped) can be completed without difficulty.
Features of selecting a rafter system option
All rafter systems consist of rafter legs, which must be connected in pairs at the top. Below, these main frame elements are combined with a screed - it can also become the basis for an interfloor attic floor. But there are some peculiarities in the design of the systems.
The fact is that roof frames are equipped in one of two types:
- layered;
- hanging.
Both of these rafter systems have found application in private residential construction.
As a rule, the specific choice depends on the design structure of the building. When the gap between the load-bearing walls is no more than 6 meters, installation of a hanging type rafter system is allowed. Its peculiarity is that the legs of the rafters rest only on the side walls.
The layered structure is more reliable and is used at the above-mentioned distance, which exceeds 6 meters, and when the room has a load-bearing wall built in the center of the house. In this case, you can abandon the sagging option if you install additional support.
Roof frame materials
For the construction of the frame part gable roof First of all you will need rafters. They will presumably be made from wood. You can build a roof frame from boards with a section of 50x150 millimeters or from timber with a section of 150x150 millimeters. It is desirable that this be material coniferous species, prepared in winter time, and the resin was not drained from it first.
The presence of resinous substances in wood, which are a natural antiseptic, significantly extends its service life. The storage conditions of materials and the degree of drying are of no small importance.
When inspecting beams and boards, pay attention to the presence of defects - they could be cracks, delaminations, the presence of traces of damage from insects - wood borers. If these shortcomings are detected, the rejected boards and beams are not used.
In addition to lumber, reinforced concrete concrete and a metal channel are used to construct the frame, but then the roof turns out to be too heavy and it is impossible to build it yourself.
In addition to the rafter legs, posts and purlins that make up the system, frame structure includes attic flooring, sheathing and counter-lattice. If the attic space is planned to be used as non-residential space, then boards with a cross-section of 50x150 millimeters will be sufficient for the flooring.
When they want to create a residential attic from the attic space, then the ceiling must be made reliable and for these purposes you will need a wooden beam with a cross-section of 150x150 millimeters. It is laid on the Mauerlat and thereby achieves the required strength.
To arrange the sheathing and counter-lattice, timber is used, but it must be thinner. Suitable lumber with a section square shape 40x40 or 50x50 millimeters. Beams of this size are strong enough to support the weight of the roof “pie”. When choosing them, pay attention to straightness, since any deviation leads to difficulties that arise in the process of roofing work.
For the construction of lathing and counter-lattice, you can also purchase a perforated profile made of galvanized metal.
In addition to the above materials you will need:
- Threaded metal studs - they are used to secure the Mauerlat, which serves as a support beam.
- Brackets and brackets for fixing the rafter legs to the mauerlat.
- Fasteners, including studs with a diameter of 8 and 10 millimeters, wood screws, which are needed to connect the rafters.
- Galvanized nails.
To install the roof frame, you need standard set tools, including:
- hammers different sizes;
- drill for creating holes;
- plane;
- grinder or saw;
- measuring devices - level, plumb line.
Methods for protecting wood for frames
Before making the roof frame of a house, it is necessary to treat its wooden elements with protective agents against rotting and fire.
For this purpose, all parts that make up the rafters, lathing and ceilings are treated with the following compounds:
- antipyretics that reduce the flammability of wood and protect wooden parts from fire roof frame;
- antiseptics, which are substances capable of destroying bacteria, they prevent the development of putrefactive processes in the material from which the ceilings and rafters are made.
The above-mentioned compositions are applied with a brush, since when using sprayers it is impossible to achieve high-quality and deep impregnation. This is done in several layers.
Some wood preservatives are toxic, so they must be applied outdoors or in a well-ventilated room. In this case, you need to use personal protective equipment.
The frame can be processed after its arrangement is completed. Then the structure is coated with fire-retardant and antibacterial compounds, and special attention is paid to the joints of the beams of the rafter system.
Do-it-yourself Mauerlat installation
The support for the frame of the roof being erected is the mauerlat, installed on the load-bearing walls. Its main function is to transfer and distribute the weight of the roof and various loads on the building envelope. Mauerlat is the basis of almost any rafter system, except for cases where the roof is created on a frame house or a timber building. In them, the function of a support beam is performed by the upper beam on the wall.
Typically, it is customary to use timber 100x150 or 150x150 millimeters as a mauerlat. The best option is to lay it “flush” with the inner surface of the load-bearing walls. In this case, rows of bricks need to be laid out outside at a level with the Mauerlat.
Along the perimeter of the building before its installation it is necessary to fill concrete blind area. After the final hardening of the composition, roofing material is laid on this base in several layers so that this material provides a sufficient degree of waterproofing and effectively prevents the absorption of moisture by the wood.
In most cases, the Mauerlat is mounted in accordance with the following technology:
- Metal fasteners with a diameter of 10 millimeters or more are inserted into the concrete base at the stage of its construction or later. To do this, holes are drilled in it and cement mortar is used to fix the studs.
- Mauerlat from solid timber with a cross section of 150x150 millimeters, they are laid along the blind area and in places where it touches the fasteners, appropriate marks are made. Holes are drilled according to them. The Mauerlat is placed on the studs so that they protrude from the timber by at least 10–15 millimeters.
- To fix this element, use nuts, placing a wide, flat washer between them and the beam. In the presence of welding machine You can save money on heels. In this case, reinforcing bars are used instead, and the nuts are welded to them.
There is another way to install the Mauerlat, when the timber is replaced with two rows of boards with a cross-section of 50x150 millimeters:
- The first row of lumber is placed around the perimeter of the walls and secured with anchor screws that have a countersunk head and a metal sleeve. To make holes in brickwork or concrete, use a hammer drill, having previously drilled the boards with a drill with a standard drill bit.
- Another row is placed on top of the first so that the joints of the boards do not coincide. In the corners wood materials put in a “dressing”.
- Both rows are connected to each other with 100 mm nails.
The second method of arranging a mauerlat greatly facilitates the movement of lumber to a height, since the boards are much lighter than timber. At the same time, the degree of strength of such a structure will be sufficient, especially when a roof is being erected for a frame house, which has a relatively low weight.
Arrangement of the rafter system - technology
The next stage of roof construction is the installation of rafters. To facilitate the work process, especially when constructing a roof frame with your own hands, the rafter beams are processed on the ground.
This will make it much more convenient to cut materials according to size, give them the required shape using a template, cut out grooves and drill holes for fasteners. Only then the components for the rafters are moved upstairs and they begin to connect them.
Frame assembly technology with hanging system the rafters look like this:
- Grooves are cut into the mauerlat for mounting rafter legs. The gap between these adjacent elements is determined when choosing the type of rafter system, but in any case it should not exceed 150 centimeters, otherwise the structure will not be sufficiently rigid. When it is planned to insulate the roof, then the distance between the rafters should be coordinated with the dimensions of the thermal insulation material. If you lay solid insulation slabs in the free space between the rafter legs, you will not need to waste time adjusting this material.
- The installation of rafters begins from the end parts (gables) of the roof. After installing them, a cord is pulled between the ridges and when aligning the intermediate rafters relative to the vertical, it is necessary to focus on it.
- The rafter legs are lowered into the grooves. To fix them in the Mauerlat, complex fasteners are used. To do this, the transverse displacement of the elements is limited by a steel bracket, and the longitudinal displacement by a bracket.
- During the installation process, you need to take into account that the rafters must extend beyond the perimeter of the building. The optimal size of the protrusion, which is usually called overhang or overhang, is considered to be 40 centimeters. As a result, the walls of the house are protected from water flowing down the roof surface. The overhang can be equipped not only with the help of rafter beams - the length of the rafters is increased by using a thin board, called a “filly”. It is attached to the rafters by means of a spacer (a short piece of board) with nails. The use of an additional board during the construction of a roof overhang is not considered a design flaw; on the contrary, the use of a “filly” makes construction easier and slightly cheaper. At the same time, overhang repair is simplified: if necessary, it is enough to replace one or several “fillies”, rather than the entire rafter beam.
- The lower ends of the rafters should be secured with strapping, which is used as a base for the attic floor. The strapping bars rest on the mauerlat.
- If you need to increase the beams for the rafters if they are not long enough, two beams are laid in an overlay with an overlap of at least one meter in size. They are secured with studs with a diameter of 8–12 millimeters.
- The rafters are connected to each other with pins - they are inserted into pre-prepared holes. To prevent the rafters from rotating around the pin axis, each pair of rafters is secured with two fasteners.
- When the roof width does not exceed 6 meters, then hanging rafters connected by a transverse beam - a tie shaped like the letter “A”. This element is made from boards with a cross-section of 50x100 or 50x150 millimeters, and attached to the rafters with self-tapping screws. You can also install tie-downs consisting of three boards with a cross-section of 30x100 millimeters, which are placed on both sides of the rafters.
- Roof trusses in the upper part they are fixed with a longitudinal ridge beam or ridge board.
- Additionally, in order to strengthen the upper assembly of the rafters, connect the ridge beam with a tightening using a piece of board. This is done to prevent the tension from bending in case of a large gap between the rafters.
The same method is used to install the roof of a frame house, although there are some minor nuances. After the installation of the rafters is completed, installation of the sheathing begins.
How to make a roof sheathing
This roof element comes in two types: solid and sparse. The choice of one depends on the roofing material used.
To build a continuous sheathing, use OSB boards or sheets of moisture-resistant plywood with a thickness of 10 millimeters. They are stuffed onto the rafters using a counter-batten. Use continuous sheathing if roll or soft materials are to be installed.
When a thinned sheathing is installed, boards or beams are placed on the rafters at intervals that depend on the size of the roof covering elements. If it is necessary to save money, to create this type of sheathing, instead of using timber, use an unedged board.
The sparse sheathing is stuffed onto the rafters from top to bottom. To increase the strength of the structure, the first of the rows from ridge beam, create without gaps. After completing the construction of the sheathing, you can begin work on thermal insulation of the roof, installation of thermal insulation and laying of the finishing coating.
Choosing a roof type
Before designing a house, its owners must decide whether the second floor will be used for living. The point is that technology frame roof under the second floor has differences, because the living space is located directly under the roof. In this case, there is no need to build the walls of the upper floor and install a roof above it.
In addition to advantages, frame roofs for the second floor also have disadvantages, including the inability to install full-fledged window openings, and it is difficult to make the living space comfortable.