The rafter system is the basis of the roof; the reliability and strength of the roof, its ability to withstand precipitation and wind depend on it. Design rafter system determined by the shape of the roof and the layout of the house, as well as the materials used. A do-it-yourself rafter system is usually made of wood, but other materials can also be used, for example, a metal profile.
Types of rafters and their application
Choosing a rafter system is a crucial step that requires knowledge of the design of each type of roof. Rafters can be:
- Layered rafters supported by a ridge girder and a mauerlat. They are used in the construction of a single-pitch roof, a simple gable roof, and also as one of the elements of a hip and sloping roof. mansard roof.
- Sliding rafters are a type of layered rafters used for wooden buildings, giving greater shrinkage. Their difference is the sliding fastening of the rafters to the Mauerlat, which makes it possible to compensate for the shrinkage of the walls without deforming the roof.
- Hanging rafters - a system of rafters tied together with crossbars or tie rods, usually used in the construction of a simple gable roof, and also as upper rafters mansard roof. In a hanging rafter system, there is no ridge purlin, and in the upper part the symmetrical rafter legs rest directly on each other.
- Sloping rafters, otherwise called corner or diagonal. They are used to make three-pitched or hipped roofs, as well as for roofs with complex geometry.
Elements of the rafter system
Any rafters are designed to distribute and transfer the roof load to the walls of the house. The main elements on which the rafters rest are:
- Mauerlat is a beam fixed to the upper plane of the walls along the perimeter of the entire house;
- Bedding - support beams laid on internal load-bearing partitions or columns;
- Floor beams of the upper floor;
- Racks and supports;
- Purlins are horizontal supporting elements laid along the axis of the roof on racks.
The roof truss consists of the following elements:
- Rafter legs - boards or timber that form the contour of the roof and are laid at a certain pitch;
- Tightenings or crossbars are horizontal elements that tighten paired rafter legs together;
- Struts - supports placed at an angle and supporting the rafter legs;
- Fillers are boards attached to the lower end of the rafters and forming roof overhangs;
Rafts are short rafters resting on diagonal rafters in a hip roof.
All these elements in private construction are usually made of wood - timber or naturally dried softwood boards. The wood is impregnated with an antiseptic, which extends its service life. The thickness and cross-section of the elements is determined by calculation.
Technology for making layered rafters
- Before construction begins, it is necessary to sketch the roof and calculate its dimensions. The cross-section and pitch of the rafters, as well as the need to install additional supports and struts, are also determined by calculation.
- Supporting elements are laid and positioned: mauerlat, floor beams and beams, racks, ridge and intermediate purlins. These operations are described in detail in articles dedicated to various types roofs:
- Make a rafter template. To do this, take a board with a width corresponding effective length rafters, with the same width, but with less thickness - it is lighter and easier to precisely adjust to the location. The board is applied to the installation site of the outer rafter with one end to the ridge girder and the other to the mauerlat.
- At the top of the template, mark the top notch. The shape of the cut should be such that the board rests on the ridge girder and at the same time fits tightly to the opposite rafter. The depth of the cut should be no more than 1/3 of the width of the board.
- After cutting out the top cut, the template is once again applied in place and the bottom cut is marked - it should rest on the Mauerlat without leaving large gaps. The end of the template is filed at an angle so that the cut is in a vertical plane.
- The resulting template is applied to the installation site of all rafter legs, checking whether adjustment will be necessary in place. If the template fits perfectly (which rarely happens), you can immediately make required amount rafter legs. If adjustments to the bottom cut are needed, then only the upper part of each rafter is cut out using templates, and the bottom cut is made in place each time.
- The rafters are placed with established calculation step. Typically it ranges from 50 to 120 cm and depends on the type of roofing covering, namely its severity, and the expected snow load. The heaviest coverings are slate and ceramic tiles, but they are rarely used nowadays. More often, the choice is made in favor of more modern, lightweight and reliable materials: metal tiles, ondulin, soft roofing. For them, the rafter pitch can be chosen to be about 100 cm without performing complex calculations.
- First, install the rafters on the gable side. The rafter leg is supported on the ridge purlin and the Mauerlat and secured to two nails 100-150 mm in each fastening point. Having installed rafter pair, they additionally fasten it: in the upper part with the help of metal plates and screws on one side and corners with a stiffener on the other, in the lower part with staples or also on the corners.
- After installing the rafters from both gables of the roof, string is pulled between them and the remaining rafters are aligned along it. The rafters are fastened in the same way.
- Install struts if the calculation results require it. The struts are made of the same material as the rafters. Apply a board of suitable length at the desired angle to the rafters and mark the bottom cut. It is important to consider what the strut will rest on: the floor beam or the beam; the shape of the bottom cut depends on this. After completing the bottom cut, the strut is placed in place and the cutting line along the rafters is marked. The prepared strut is placed between the beams and rafters and secured with metal plates or corners.
Installation of roof struts
Technology for making hip diagonal rafters
- Since the rafters are for hip roof install diagonally usual ways their fastenings are not suitable. In addition, the load on diagonal rafters is much higher than on layered or hanging ones, so the material for their implementation must have a larger cross-section. You can use timber with a thickness of 100 mm or more, but practice shows that it is more convenient to make these rafters from two folded and fastened boards of standard thickness.
- The upper end of the diagonal rafters rests on the racks, and the lower end on the mauerlat bars converging at right angles. They are marked in place, and their main feature is that the cuts are made not perpendicular to the plane of the board, but at an angle of 45 degrees. When making rafters from spliced boards, first one side is made with oblique cuts, then the second, in a mirror image.
- The boards are pulled together using screws, nails or studs. Fasten hip rafters using pads and screws.
The video will help you better understand the basic techniques for constructing a rafter system with your own hands.
When making any rafter system with your own hands, it is important to carefully secure all components and connections and remember that the roof is the main protection of your home from bad weather. Therefore, it is important not only to make a high-quality frame, but also to choose a suitable one, for example, corrugated board, and lay it correctly.
Construction of a private house is quite a long and responsible task. Here it is extremely important not to rush and competently plan not only the nuances of the interior of the house, but also take care of its appearance. One of the main components of the overall interior is the roof.
DIY gable roof
There are many options for roofing, but the gable roof is the most common, especially when it comes to private construction. Exactly simple design(consists of beams and boards that are installed without much physical effort) most inclines owners of private houses to choose this type of roofing.
During construction individual house One of the main steps is the installation of the roof, so many people often ask the question: how to make a gable roof with your own hands?
Despite the fact that in last decades appeared on the construction market various options roof configuration, gable remains the most common, as it has a number of operational advantages.
The technology for installation, fastening and covering of the roof has been carefully developed. When using metal tiles, corrugated sheets, slate, ondulin or other materials, the technique and sequence of operations remains the same.
Before starting the construction of a house, cottage or any other building, it is necessary to develop drawings of individual elements and a design of all components of the structure. And the roof is no exception.
The shape and design of the roof is selected based on the size and parameters of the future building. In addition, the load indicators that a gable roof will experience during operation must be taken into account.The smaller the angle of inclination, the less influence it has from rain, wind and snow. At the same time, we must not forget that if the angle of inclination is less than 40°, this limits the use of the attic space.
In this case, only a broken version of the gable roof shape can be equipped with an attic. And if the width between the walls of the building exceeds 6 m, the rafters need to be reinforced with purlins.
You should also know that different types of buildings have their own indicators and features of roof construction. For example, when arranging a roof for a bathhouse, the most best option– use a gable roof with a slope of 45° – 50°.
When calculating the need for materials, you should remember that the mass future design made of corrugated sheets should be as minimal as possible, which will avoid creating additional loads on the foundation and walls.
The strength of boards, timber and other lumber is determined by several factors:
- cross-sectional size;
- wood texture.
The pediment does not have to be finished with the same material. If you plan to store only old things and magazines in the attic that you would hate to throw away, you can line it up with clapboard.
In order to determine the need for roofing material, you need to find out the total area. Calculation is considered one of the main stages of design. Almost all measurements should be made correctly, without any inaccuracies.
Even a small, insignificant mistake can lead to unplanned high costs for additional purchase of materials. When the construction of a new building is carried out with one’s own hands without the help of specialists or construction crews, every penny counts. And there shouldn't be any mistakes.
When determining total area gable roof, it is enough to calculate the parameters of one slope and multiply by two. Little things like holes for a chimney or a roof window can be easily neglected.
Features of the design of a gable roof with your own hands
When starting to design a gable roof type and develop drawings, it is assumed that it will be installed on two walls of the building. The shape of the roof is developed simultaneously and in accordance with the design of the house.
When building a bathhouse, country house or other similar structure, it is most convenient to use hanging rafters. During construction big house Layered rafters are more often used. In this case, the rafter system has a more complex configuration. The photos shown on our portal show options for the rafter system.When installing a gable roof with your own hands, you must strictly follow the sequence of actions when installing the rafters. But you need to remember that you can’t do it without outside help.
This design includes the following elements and components:
- Mauerlat;
- skates and braces;
- rafter system;
- sheathing;
- roofing material;
- insulation.
But if it was decided to equip an attic under the roof, it is best to use a broken configuration. The attic is limited by several slopes and gables.
Installing an attic space requires additional costs. And at the same time, the construction of a building with living space in the attic significantly increases the level of comfort, including its market value.
Do-it-yourself Mauerlat installation
The timber that lies along the perimeter of the building at the top level of the walls is called the mauerlat by the builders. His top harness is responsible for taking on the entire load from the roofing system and additionally distributing it to the walls and foundation.
To build a mauerlat, a timber with a cross-section corresponding to the width of the walls is taken. Before starting the installation process, it must be impregnated with special solutions to protect it from rotting and fire. The installation of the Mauerlat is carried out in stages. Its outer edge should be flush with the plane of the wall.
From our video and photo files you can see that the timber is attached to the wall using studs. The Mauerlat must be laid correctly and reliably, since it plays the role of a foundation for a gable roofing system.
Installation can be carried out different ways. If the walls are made of brick, then initial stage During construction, wire rod is embedded in the masonry. Drilled into the timber through hole, through which this wire is passed. Then it should be screwed securely.Sometimes metal pins are attached instead of wire. Their diameter is from 10 mm. Accordingly, the beam is put on studs and secured with nuts and wide washers.
In both options, fastening can be done with your own hands without outside help. In some cases, a pediment is attached to the Mauerlat with the lower part, which increases the level of stability.
Do-it-yourself installation of floor beams
In order to carry out competent installation of the ceiling for a house, a beam with a section of 200x100 mm is used. For example, for a bathhouse or small country house the cross-section is selected based on the dimensions of the structure.
First, two outer beams are attached, which are spread along the entire length of the building. Next stage– mark fixation points for other floor beams.
Using a construction tape measure and a regular cord, the distance between the outer beams is divided into segments 60 cm long. Rafters will be mounted on the beams with exactly the same spacing.
All beams are attached to the Mauerlat with 200 mm nails, after which it is advisable to put temporary flooring made of boards or corrugated sheets on the beams. Fastening can be done using metal corners and self-tapping screws. When installing beams, you must maintain a specific amount of extension beyond the walls of the house. The width of the cornice will depend on the size of the extension. As practice shows, 50 - 60 cm is enough. At this stage, it is necessary to take into account the fact that the pediment will be sewn up at the ends of the roof. For garden house or baths, you can perform it in a simplified form.
If the plan provides for an attic sloping roof, then the pediment must have a significant area. It is also necessary to provide for the possibility of arranging an overhang and low tide. Before fastening, the beams laid out on the walls must be leveled in a horizontal plane.Do-it-yourself installation of a gable roof rafter system
The design of the rafter system requires the use of components identical to each other. After laying and securing the floor beams, the ridge beam is installed. To do this, 100x50 mm racks are mounted through the center of the building. Their height should correspond to the height of the walls from the floor to the top of the mauerlat. The rack is secured using spacers.
When constructing a gable roof with your own hands, it is necessary to monitor the quality level of the operation after completing each stage. Making your own template is very easy. The rafter board is applied with one end to the beam and the other to the beam. Control lines are emphasized at both ends, along which excess pieces are sawed off. Thus, the template is ready, and from it you can prepare the required number of rafters for the building.
Installation is performed in in a certain order. Having laid one rafter, you need to immediately begin attaching the opposite one. Fastening to the ridge beam is carried out with nails, and to the floor beam - with a bracket or metal corners.
The video demonstrates how this is done. Regardless of the shape of the roof, horizontal crossbars and vertical posts are installed under the rafters.Selection of material for rafters
When calculating the material for a gable roof, it is necessary to select wood High Quality no wormholes or damage. The presence of knots for rafters, beams or mauerlat is not allowed.
If we are talking about sheathing knots, there should be a minimum. The wood must be as durable as possible and pre-treated with special preparations to improve its quality and properties.
Calculation of the angle of inclination of a gable roof
The angle of inclination is determined by many factors, but the first thing that matters is the roofing material. Since each of them puts forward its own operational requirements:
- soft roof – 5-20°;
- slate, corrugated sheets, metal tiles, ondulin - 20-45°.
Arranging a pediment with your own hands
After installation truss structure completed, the pediment is sewn up. It is extremely unacceptable to build a house and not decorate the pediment. IN Lately it is equipped with corrugated sheets. This correct solution, although when decorating the facade in this case certain difficulties may arise.
In order to complete the pediment, the frame must be installed. At the same time, one should not forget about window opening. IN attic a window is required for ventilation. Very often the pediment is sheathed with clapboard or floor lath. When finishing the façade, the pediment is decorated in various ways.
Making a cornice with your own hands
Proper installation of a gable roof implies the presence of a cornice structure along the entire perimeter. Practice shows that for any building it is necessary to hem the cornice. It is designed to divert rainwater from getting under the foundation.
If the building is equipped with a metal drainage system, then the brackets for fastening the ebb and flow should be installed and secured at this stage. The drainage system, made of plastic, is attached directly to the cornice. In order to hem the cornice from below, you can use siding or sheets of corrugated board.
DIY lathing and insulation
First you need to fix the strip on the roof waterproofing film. This should be done at the bottom of the slope. It is attached to the rafters with a construction stapler. After that, counter-lattice slats are mounted on the rafters. If the roofing device is to be insulated, then heat-insulating material is placed on the film.
Lathing for any building is carried out with a specific roofing material in mind. To secure the profiled sheet, the lathing is the same as when using slate. The use of corrugated sheets significantly increases the cost of the structure, but makes it much stronger.
The sheathing device can be made in several versions. The first is designed for hard roofing such as metal tiles, corrugated sheets or slate. The second one is performed under soft roof. For example, for a bath I use roofing felt.
Specific types of sheathing and roofing material are selected during design. It is possible to erect a modern building with a gable roof only if many nuances and details are taken into account.
Installation of roof sheathing
The lathing is installed in any case and is intended for more convenient and safe movement on the roof during the work process, as well as for fastening roofing material.
The pitch for the sheathing is determined by the type of roofing material, for example:
- for metal tiles – 350 mm;
- a continuous sheathing is laid under the soft roof;
- for slate and corrugated board – 440 mm.
What tools might you need to build a gable roof with your own hands?
After choosing a design roofing pie and rafter system, you can adjust the list necessary tools, which will be needed for the construction of the roof. For overhead work, it is very convenient to have a professional tool belt. They will always be at hand in one place. Its kit should include:
- Pencil or marker.
- Roulette.
- Lace (beat).
- Hammer.
- Putty knife.
- Scissors for roofing material.
- Roofing knife.
- Hacksaw.
- Construction tape.
- Screwdriver with attachment for self-tapping screws.
Sometimes there may be a need for polyurethane foam and mastic-based adhesives. Some devices can greatly simplify the installation process.
Roofing details
You should pay attention to additional components that also affect the durability and functionality of the roofing system. The use of low-quality self-tapping screws (with a thickness of EPDM gaskets less than 2 mm or without a manufacturer’s mark) leads to roof leaks and deformations. Poor quality paintwork on the fittings may become damaged over time and damage appearance the entire roof.
Another component that is important when installing a roof is snow retainers, the absence of which increases the risk of an avalanche of snow from the roof. In addition, this may result in damage to the drainage system, building or vehicle located under the roof.
The next problem that also cannot be ignored is condensation. It is associated with insufficient ventilation in the under-roof space. To improve air exchange in the roof, it is necessary to provide for the installation of ventilation outlet elements that will allow ventilation of the under-roof space.Installation of roofing material
Recently, many new products have appeared on the construction market. This trend also affected the gable roof type.
The time-tested and familiar slate was replaced by metal tiles and ondulin. A roof made of corrugated sheets lasts longer and is more reliable, provided that it is installed correctly. To carry out roofing work with your own hands, you should have a good knowledge of the technology and correct sequence actions, starting with how to properly cut the material and ensure its lifting to the attachment point.
General rules
For construction good home or buildings, it is not at all necessary to buy an original project. It is much more effective to familiarize yourself in detail with the structure of buildings that have already been built in the area. Buildings with spiers and domes look quite attractive.
However, the usual gable roofs characterized by harmony of style and form. Their main advantage lies in functionality and reliability.
Conclusion
As you can see, despite its apparent simplicity, installing a gable roof rafter system with your own hands contains many pitfalls. However, based on the recommendations given, you can build a reliable structure without any problems.
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When planning the construction of low-rise residential, utility or commercial buildings, most designers choose a gable roof structure. This is due to the relatively simple installation technology, increased structural reliability, effective removal of precipitation from the roof and unpretentiousness to operating conditions. However, to achieve all the benefits, you need to competently design and install rafters for a gable roof with your own hands.
Exterior view of a house with a gable roof
Gable roofs represent two inclined planes rectangular shape(ramps) that rest on the rafter system. The side parts are made blank or windows and trim are installed on them. The main parameters of such a roof are: the angle of inclination and the location of the ridge relative to the center line passing through the walls perpendicular to the slopes. That is gable design it does not have to have the same slope of the slopes or have a symmetrical appearance.
A bunch of original projects They use an asymmetrical design of slopes to take into account certain climate features, or to improve the design of the facade. It is worth noting that such solutions are very original, but in practice they are quite difficult to implement. This is due to the following reasons:
- The load on the walls and foundation increases where the roof ridge is displaced. As a result, calculations can become significantly more complicated, especially when using heavy roofing materials such as slate or ceramic tiles.
- It is necessary to manufacture separate structural elements for each slope, which can significantly increase construction time.
- The pressure of wind flows can have a significant influence on the roof at large angles of inclination of the slopes. Therefore, it will be necessary to take into account the preferential direction of the winds when making calculations.
Basic elements of a pitched roof system
Before making rafters for a gable roof, you need to create a project and also study all the structural elements. You will need to design the following main components:
- Mauerlat. Provides load transfer of the roof structure to load-bearing walls object, creating its uniform distribution. The timber is made from hardwood wood such as larch, oak, ash. The minimum permissible cross-section is 100x100 mm. It is allowed to use not only solid timber, and also glued, but with a section of 100x150 mm.
- Rafters. The main structural element, which is designed to form a load-bearing frame, absorb the load of the roofing material through the sheathing and transfer the load to the mauerlat. The distance between the rafters of a gable roof ranges from 0.6 to 1.2 m, depending on the weight of the roofing material and the amount of precipitation in a particular area.
- Puff. A special design used to fix two inclined beams of slopes at a given angle of inclination, which is mounted at a level just above the beams or slightly below the ridge. It is used in layered types of roofs.
- Rack. It is a vertically installed and firmly fixed element that performs the load-bearing functions of the roof. It is usually installed on the walls of a building to partially transfer the roof load. Gives additional rigidity to the structure.
- Run. There are two types: side and ridge. The side beam is a beam supported on posts and located parallel to the ridge beam. Allows you to prevent the slope from bending under significant loads. The ridge run is installed along the line where one slope joins another and serves as a support for the ridge.
- Strut. It represents auxiliary supports for racks, which are located at an angle of 45 0 to the load-bearing beams of the slopes in order to increase the area of contact with the racks and reduce the risk of deformation of the slope.
- Sill. Serves as a fulcrum for the strut and stand.
- Lathing. It is used to fix the rafter system in the transverse direction, transfer the load of the roofing material and its fastening, as well as provide resistance to loads in the runs between the load-bearing beams.
Helpful information! Due to increased snow and ice loads on roofs, struts for northern regions can be installed not only longitudinally, but also diagonally. Thus, a significant part of the load is carried by the racks, and not the walls of the building.
Calculation of the length and pitch of rafters
When installing rafters for a gable roof with your own hands, you need to observe a fastening step of 0.6-1 m. The choice depends on the design loads, taking into account the safety factor. The smaller the step, the stronger design And more consumption building materials. A large interval of 0.8-1 m can only be used when laying light roofing sheets and inclination angles of 15 0 -20 0. It is recommended to choose a step within 0.6-0.8 m.
The length of the beams, knowing the angle of inclination of the slopes and the distance between the two walls of the object, can be easily calculated using the Pythagorean theorem. However, the actual length needs to be increased by 60-70 cm, which will be used for their joining, as well as for the overhang of the slopes of approximately 0.5-0.6 m.
At the heart of every roof is a large number of beams, rafters, posts and purlins, which are collectively called the rafter system. Behind centuries-old history Many types and methods of its organization have accumulated, and each has its own characteristics in the construction of nodes and cuts. Let's talk in more detail about what the rafter system of a gable roof can be and how the rafters and other elements of the system should be attached.
Design of a gable roof truss system
In cross-section, a gable roof is a triangle. It consists of two rectangular inclined planes. These two planes are connected at the highest point into a single system by a ridge beam (purlin).
Now about the components of the system and their purpose:
- Mauerlat is a beam that connects the roof and walls of a building, serves as a support for rafter legs and other elements of the system.
- Rafter legs - they form the inclined planes of the roof and provide support for the sheathing under the roofing material.
- Ridge purlin (bead or ridge) - combines two roof planes.
- A tie is a transverse part that connects opposite rafter legs. Serves to increase structural rigidity and compensate for thrust loads.
- Lezhny - bars located along the mauerlat. Redistribute the load from the roof.
- Side purlins - support the rafter legs.
- Racks - transfer the load from the purlins to the beams.
There may still be fillies in the system. These are boards that extend the rafter legs to form an overhang. The fact is that to protect the walls and foundation of the house from precipitation, it is desirable that the roof ends as far from the walls as possible. To do this, you can take long rafter legs. But the standard length of lumber of 6 meters is often not enough for this. Ordering non-standard is very expensive. Therefore, the rafters are simply extended, and the boards with which this is done are called “fillies”.
There are quite a few designs of rafter systems. First of all, they are divided into two groups - with layered and hanging rafters.
With hanging rafters
These are systems in which the rafter legs rest only on the external walls without intermediate supports (load-bearing walls). For gable roofs, the maximum span is 9 meters. When installing a vertical support and a strut system, it can be increased to 14 meters.
The good thing about the hanging type of gable roof rafter system is that in most cases there is no need to install a mauerlat, and this makes the installation of rafter legs easier: there is no need to make cuts, just bevel the boards. A lining is used to connect the walls and rafters - wide board, which is attached to studs, nails, bolts, crossbars. With this structure, most of the thrust loads are compensated, the impact on the walls is directed vertically downwards.
Types of rafter systems with hanging rafters for different spans between load-bearing walls
Gable roof rafter system for small houses
Exists cheap option rafter system when it is a triangle (photo below). Such a structure is possible if the distance between the external walls is no more than 6 meters. For such a rafter system, you can not make calculations based on the angle of inclination: the ridge must be raised above the tie to a height of at least 1/6 of the span length.
But with this construction, the rafters experience significant bending loads. To compensate for them, either rafters of a larger cross-section are taken or the ridge part is cut in such a way as to partially neutralize them. To give greater rigidity, wooden or metal plates are nailed on both sides at the top, which securely fasten the top of the triangle (also see the picture).
The photo also shows how to extend rafter legs to create a roof overhang. A notch is made, which should extend beyond the line drawn from interior wall up. This is necessary to shift the location of the cut and reduce the likelihood of the rafter breaking.
Ridge knot and fastening of rafter legs to the backing board when simple version systems
For mansard roofs
Option with installing a crossbar - used when. In this case, it serves as the basis for lining the ceiling of the room below. For reliable operation systems of this type, the crossbar cut must be hingeless (rigid). The best option is in a semi-frying pan (see picture below). Otherwise, the roof will become unstable to loads.
Please note that in this scheme there is a Mauerlat, and the rafter legs must extend beyond the walls to increase the stability of the structure. To secure them and dock them with the Mauerlat, a notch is made in the form of a triangle. In this case, with an uneven load on the slopes, the roof will be more stable.
With this scheme, almost the entire load falls on the rafters, so they need to be taken with a larger cross-section. Sometimes the raised puff is reinforced with a pendant. This is necessary to prevent it from sagging if it serves as a support for ceiling cladding materials. If the tie is short, it can be secured in the center on both sides with boards nailed to the nails. With a significant load and length, there may be several such belays. In this case, too, boards and nails are enough.
For large houses
If there is a significant distance between the two outer walls, a headstock and struts are installed. This design has high rigidity, since the loads are compensated.
With such a long span (up to 14 meters), it is difficult and expensive to make the tie in one piece, so it is made from two beams. It is connected by a straight or oblique cut (picture below).
For reliable joining, the connection point is reinforced with a steel plate mounted on bolts. Its dimensions must be larger than the dimensions of the notch - the outermost bolts are screwed into solid wood at a distance of at least 5 cm from the edge of the notch.
In order for the circuit to work properly, it is necessary to make the struts correctly. They transfer and distribute part of the load from the rafter legs to the tie and provide structural rigidity. Metal pads are used to strengthen connections
When assembling a gable roof with hanging rafters, the cross-section of lumber is always larger than in systems with layered rafters: there are fewer load transfer points, therefore each element bears a greater load.
With layered rafters
In gable roofs with layered rafters, the ends rest on the walls, and the middle part rests on load-bearing walls or columns. Some schemes push through the walls, some don't. In any case, the presence of a Mauerlat is mandatory.
Non-thrust schemes and notch units
Houses made of logs or timber do not respond well to thrust loads. For them they are critical: the wall may fall apart. For wooden houses, the rafter system of a gable roof must be non-thrust. Let's talk about the types of such systems in more detail.
The simplest non-thrust rafter system diagram is shown in the photo below. In it, the rafter leg rests on the mauerlat. In this version, it bends without pushing the wall.
Pay attention to the options for attaching the rafter legs to the Mauerlat. In the first, the support area is usually beveled, its length being no more than the section of the beam. The depth of the cut is no more than 0.25 of its height.
The top of the rafter legs is laid on the ridge beam, without fastening it to the opposite rafter. The structure turns out to be two pitched roofs, which in the upper part are adjacent (but not connected) to one another.
The option with rafter legs fastened at the ridge part is much easier to assemble. They almost never push against the walls.
To operate this scheme, the rafter legs at the bottom are attached using a movable connection. To secure the rafter leg to the mauerlat, one nail is driven from above or a flexible steel plate is placed from below. See the photo for options for attaching rafter legs to the ridge girder.
If you plan to use heavy roofing material, you need to increase bearing capacity. This is achieved by increasing the cross-section of the rafter system elements and strengthening the ridge assembly. It is shown in the photo below.
Reinforcing the ridge assembly for heavy roofing material or for significant snow loads
All of the above gable roof schemes are stable in the presence of uniform loads. But in practice this practically never happens. There are two ways to prevent the roof from sliding towards a higher load: by installing a screed at a height of about 2 meters or by struts.
Options for rafter systems with contractions
Installing contractions increases the reliability of the structure. In order for it to work properly, it needs to be secured to them with nails at the places where it intersects with the drains. The cross-section of the timber for the scrum is the same as for the rafters.
They are attached to the rafter legs with bots or nails. Can be installed on one or both sides. See the figure below for attaching the screed to the rafters and ridge girder.
In order for the system to be rigid and not “creep” even under emergency loads, it is enough in this option to ensure rigid fastening of the ridge beam. In the absence of the possibility of its horizontal displacement, the roof will withstand even significant loads.
Layered rafter systems with struts
In these options, for greater rigidity, rafter legs, also called struts, are added. They are installed at an angle of 45° relative to the horizon. Their installation allows you to increase the span length (up to 14 meters) or reduce the cross-section of beams (rafters).
The brace is simply placed at the required angle to the beams and nailed on the sides and bottom. Important Requirement: the strut must be cut accurately and fit tightly to the posts and rafter leg, eliminating the possibility of it bending.
Systems with rafter legs. The top is a spacer system, the bottom is a non-spacer system. The correct cutting nodes for each are located nearby. Below are possible strut mounting schemes
But not in all houses the average load-bearing wall is located in the middle. In this case, it is possible to install struts with an angle of inclination relative to the horizon of 45-53°.
Systems with struts are necessary if significant uneven shrinkage of the foundation or walls is possible. Walls can settle differently depending on wooden houses, and the foundations are on layered or heaving soils. In all these cases, consider installing rafter systems of this type.
System for houses with two internal load-bearing walls
If the house has two load-bearing walls, install two rafter beams, which are located above each of the walls. The beams are laid on the intermediate load-bearing walls, the load from the rafter beams is transferred to the beams through the racks.
In these systems, a ridge run is not installed: it provides expansion forces. The rafters in the upper part are connected to one another (cut and joined without gaps), the joints are reinforced with steel or wooden plates, which are nailed.
In the upper non-thrust system, the pushing force is neutralized by the tightening. Please note that the tightening is placed under the purlin. Then it works effectively ( top diagram on the image). Stability can be provided by racks, or joints - beams installed diagonally. In the spacer system (in the picture it is below) the crossbar is a crossbar. It is installed above the purlin.
There is a version of the system with racks, but without rafter beams. Then a stand is nailed to each rafter leg, the other end of which rests on the intermediate load-bearing wall.
Fastening the rack and tightening in the rafter system without a rafter purlin
To fasten the racks, 150 mm long nails and 12 mm bolts are used. Dimensions and distances in the figure are indicated in millimeters.
If you are building your own house and have already reached the stage of erecting the roof, then from our article you can learn how to do it yourself. Roof - essential element any residential structure, so it should be given Special attention. Not only the comfort in the house in terms of temperature, but also the overall safety of the building depends on the quality of the roof. So, let's figure it out step by step instructions for the construction of this house assembly.
Preparation and calculations
It is important to understand that the roof of a house is a complex and important structural element. To construct it, it is necessary to clearly calculate the amount of material, as well as take into account future loads. We invite you to familiarize yourself (in the table) with the average options for building materials for constructing a gable roof.
IN mandatory calculate the exact volume of material based on the size of the roof of your house. You can purchase material with a small reserve, taking into account possible errors and defects. It is recommended to draw up a drawing of the future structure. To do this, by the way, you can use modern computer programs, which will help you calculate the amount of material needed. After the calculations, we proceed to the actual execution of the work.
Mauerlat is actually load-bearing beam, which is installed on the top of the erected walls and plays the role of support for the entire roof structure. For the Mauerlat we choose a beam with a cross section of 100×100 mm or 150×150 mm, depending on the size of the frame and its future weight.
The Mauerlat can be installed in several ways. The most common of these is to attach the timber directly to the top of the wall. To do this, metal studs are attached to the wall, and holes are made in the timber for fastening. A layer is laid under the Mauerlat insulating material, after which the timber is “put on” the studs and secured with bolts. If the wall is wide, the beam can be covered with brick, which will give the roof base greater strength.
You can also fix the Mauerlat using concrete putty, but the best option There will still be fixation of the timber on special studs. However, for greater strength, you can use several installation options at once.
The gable roof of a house is made with your own hands strictly step by step. After installing the Mauerlat, we proceed to the collection and installation of the rafter system. In our roof version, this design is an A-shaped element that works on the principle of expansion. Loads must be taken into account, so before installing the system it is necessary to strengthen opposite walls. For this, a beam is used (the cross-section can be selected similar to the Mauerlat), which is attached at the level of the ceiling beams.
By the way, the ceiling beams are laid before installing the rafters. The beams are fastened using corners. The installation step of ceiling beams depends on technical features your home, but should not be less than 30 cm. Fix the beams securely and constantly check the strength of the structure.
If it is possible to lift a fairly heavy load to the roof level, the system can be assembled on the ground. Otherwise, the system is assembled to ceilings. We take the beams necessary for the rafter legs and form a triangular structure, connecting the parts with nails. The triangle is installed with rafters on the mauerlat. Be careful and be sure to take into account the desired roof height right away so that you don’t have to redo the triangles in the future. Do not forget to check the vertical installation using a level and securely fix the structures to avoid distortions. You can temporarily use additional fasteners in the form of nailed boards, which can be easily dismantled at the end of the work.
Important: First of all, we install side structures on each side of the house.
We firmly attach the rafter leg to the mauerlat. For this we use metal pads. You should end up with a securely fixed triangular structure, which will act as a kind of “template” for continuing work. Taking into account the size of the beam and the angle of inclination of the rafters, we assemble new triangles and install them one by one on the mauerlat. The number and pitch of rafters depends on the size of the roof.
We strengthen the sides of the triangle with transverse boards (we nail them in the center of each side) and install the racks on the beds. They will play the role of additional support and will prevent the roof from deforming. We attach a ridge girder to the top of the entire system.
This element represents the front “wall” of the roof, continuing existing wall Houses. In order for the gable roof of a house to look beautiful and be strong with your own hands, it is necessary to strictly maintain the vertical levels of the gables and, accordingly, the rafter system. It is also important to ensure reliable fixation, since the roof will be exposed to precipitation and wind, which can lead to distortions. You should also take into account the weight of the future roofing, so you should never neglect attention to the reliability of fastening.
The pediment looks like a triangular structure, which can be assembled both on the ground and directly at the work site. You can provide for a window at the gable. The pediment is attached from below to the mauerlat, and from above to the ridge girder. You can sew up the pediment both at this stage and at any subsequent ones. As a rule, boards of 50×100 mm or 50×150 mm are used for this. The boards can be mounted either vertically or horizontally - your choice.
The inside of the pediment must be insulated and covered with an insulating layer. You can use materials and technology that we will describe in the next section. As for the outside of the gable, you can leave it as is, or you can cover it with siding, which will give your roof a beautiful look.
Lathing and insulation
To make your own gable roof reliable, be sure to insulate it. Can be used as insulation various materials, for example, the very popular mineral wool or other options based on it. Be sure to provide a vapor and waterproofing layer.
We lay the waterproofing layer directly on the rafters and fix it. Next we lay mats from thermal insulation material, placing them between the rafters with reliable fixation. Next, we lay a layer of vapor barrier, which we place with inside roofs. We fix the connections of the layers using a special adhesive tape. You can immediately install a finishing layer on top of the insulating material, or you can postpone this stage until later.
Now let's move on to the sheathing. Along existing rafters we lay the beam - counter-lattice. The task of this element is to create a gap between the roofing material and the insulation. This helps remove moisture generated by convection warm air from the ceiling and attic.
Next, we install the direct sheathing. Here everything depends on what kind of roofing material you are going to choose. For example, for tiles the sheathing pitch should be about 50 mm, and for slate or wide tiles - from 100-150 mm. In other words, it is necessary to take into account the size and weight of the future roofing material. In some cases it can be done at all continuous sheathing. By the way, this option is considered universal, that is, suitable for any type of coating. But this significantly increases consumption building material and the very weight of the entire roof.
Installation technology differs depending on the type of coating. For example, when installing bitumen shingles should first be laid on the sheathing underlay carpet with an overlap of layers of approximately 150 mm and fix it securely. The carpet can be laid both along and across the existing sheathing, the main thing is to fix it securely.
Next, we install the cornices, if they are included in the project. Cornice strip attached directly to the lining and secured with nails or self-tapping screws. Do not forget to install special brackets for installation into the cornice drainage system. After this, attach to the ends of the roof end strips and proceed to laying the tiles.
We start laying from the center of the eaves overhang, in both directions to the edges, moving layer by layer to the top of the roof. The tiles have an adhesive layer protected by film - tear it off and glue each tile to the lining. We fix it with nails in four places. Next, we repeat the procedure with each subsequent tile. At the ends, the protruding edges of the tiles must be carefully trimmed and the edges sanded. Don't forget to make roof penetrations - special holes for, for example, an antenna or a chimney. To do this, the tile is drilled into in the right place, and the hole is reinforced with rubber around the edges.
A special ridge tile of a suitable shape is mounted on the roof ridge. Here it is necessary to overlap the laying by about 5 mm to avoid rainwater from getting under the material. Installation of roofing using other materials is carried out in approximately the same way, taking into account certain nuances for each coating option.
Your DIY gable roof is ready. Now you can move on to interior decoration attic and work on covering wood with varnish, paint or other suitable materials. As you go, there is nothing complicated in this process: you will need necessary materials, several assistants, tools and 2-3 days to work.