Construction of a garage close to a residential building is a rational solution that allows you to save the useful area of the site and reduce the cost of building one of the walls. However, it is at the point where the two buildings are connected that the most complex engineering unit arises, requiring special attention. single-pitched roof In this case, it is the most common and technologically correct choice, ensuring efficient flow of water and snow.
Errors at the design stage of the roof can lead to leaks not only in the garage box itself, but also to wet load-bearing walls of the main house. This is fraught with the appearance of mold, the destruction of the insulation and even damage to the foundation. In this article, we will discuss in detail how to correctly calculate the angle of inclination, choose materials and, most importantly, qualitatively seal the adjoining roof to the wall.
The success of the entire operation depends on understanding the physics of moisture movement and the temperature expansions of materials. Tight ligament. The truss system of the garage and the house is prohibited, since the buildings may have different shrinkage. Competent approach will create a durable design that protects the car and retains heat in the home.
Selection of a constructive solution and calculation of the bias
The first step is to determine the geometry of the future roof. For attached garages, a one-stop scheme is almost always used, where the rafters rest one end on the garage mauerlat, and the other on the wall of the house. Inclination angle Ringray is a critical parameter that directly depends on the chosen roofing. If you make the stingray too flat, water will linger on it, which will lead to corrosion of metal or rotting of organic matter.
The minimum allowable slope for different materials is strictly regulated by manufacturers. For example, for asphalt shingles requires a steeper slope than for profnational flooring. Calculation of the height of the rear of the roof is made by the formula, taking into account the width of the garage and the sine of the angle of inclination.
When designing, you need to consider the height of the snow cover in your area. If the garage is wide, the ramp should be steep enough that heavy snow mass does not push the cover. For the middle strip of Russia, an angle of 15 to 25 degrees for metal coatings is considered optimal.
- 📐 For profnatsil minimum angle is 8-12 degrees, but it is better to do from 15.
- 🏠 For soft asphalt shingles, a solid flooring and a slope of at least 11-15 degrees are required.
- 🧱 Slate or ondulin requires a slope of 15 to 25 degrees depending on the model.
⚠️ Warning: Never make the roof of the garage below the level of the window or basement of the house. Water should drain from the roof into a storm drain or gutter, rather than washing away the foundation of the main building.
Materials for the truss system and coating
The frame of the roof of the garage is most often made of dry trimmed board or a beam of coniferous species. Wood It should be treated with flame retardants to prevent rotting and fire. The section of the truss legs is selected based on the length of the span: for a garage with a width of up to 4 meters, a board of 50×150 mm or 50×200 mm is usually enough.
As a roofing covering for garage extensions, sheet materials are the most popular. Fresh-natil with polymer coating has high strength and ease of installation. Metal roofing is more aesthetic, but requires more complex installation and has more waste when cut. For the budget option is often used floaterThey are placed on a solid base.
You should not save on fasteners. The screws must have EPDM-layers for sealing the hole and anti-corrosion coating. Using conventional nails or screws without rubber washers for metal is unacceptable, as it is guaranteed to lead to leaks in a few seasons.
☑️ Verification of materials
Technology of installation of the truss system
Installation begins with the installation of support bars - mauerlats. On the wall of the house is attached the upper bar, and on the walls of the garage - the lower. It is important to ensure the horizontality of the lower mauerlat, since the smoothness of the entire ramp depends on it. Mounting to the wall of the house is carried out through anchor bolts or chemical anchors, having previously drilled holes in brick or concrete.
The step of installing rafters depends on the weight of the roofing material. For lightweight flooring, the distance between the axes of the boards can be 600-800 mm, and for heavy tiles or with a large snow load, the step is reduced to 400-500 mm. The rafters are laid on the edge and fixed with metal corners or brackets.
Particular attention is paid to overhangs. The cornice overhang (front) should be at least 40 cm so that water does not flow on the wall of the garage. Side overhangs make about 20-30 cm. All wooden elements in contact with masonry must be laid with a layer of waterproofing, for example, two layers of ruberoid.
| Parameter | Value/Requirement | Note |
|---|---|---|
| Section of rafters | 50x150 mm | For a 4-meter span |
| Step of the rafters | 600-800 mm | Depends on snow and cover |
| The cornice's departure | 400-500 mm | Protecting walls from oblique rain |
| Fastening to the wall | Ankera/Kronsteins | Without a hard link to the house. |
⚠️ Attention: When attaching the support beam to the wall of the house (it is categorically impossible) to use the mounting foam as the main load-bearing or waterproofing element. The foam is hygroscopic and is destroyed by ultraviolet radiation.
The device of adjoining the roof to the wall of the house
The most important stage of construction of the annex is the organization of the adjoining node. This is where the leaks most often occur. There are two main ways to solve this problem: open and closed. The closed method, using wall stropping, is considered more reliable for brick and concrete structures.
The technology is as follows: at a height of 10-15 cm above the roof level in the wall of the house, a string (horizontal groove) with a depth of 2-3 cm is broken through. The upper shelf of the metal apron (adjacent bars) is injected into this pen. The place of the establishment is filled with sealant or cement mortar. The lower part of the apron is screwed to the rafters or crate on top of the roofing material.
If you can not lay the wall (for example, a house made of aerated concrete or with a ventilated facade), open adjoining slats with increased sealing are used. In this case, the upper edge of the bar is pressed against the wall with a pressurized slat, and the joint is abundantly smeared with a polyurethane-based roofing sealant. Hermetic It must maintain elasticity at temperature changes to compensate for thermal expansion of materials.
Nuances for wooden houses
If the house is wooden, you can not scroll the wall. Use special elastic tapes for adjoining or wide metal aprons that are winded under siding or skinning, but do not crash into the log rigidly. Make sure to leave a gap to compensate for the shrinkage of the log.
Waterproofing and insulation of the garage roof
Even if the garage is not heated, waterproofing is necessary to protect the truss system from condensation that forms on the back of the metal roof sheet. This is what is used for. waterproofing membrane Or a film that is placed on top of the rafters under the crate. The canvases are spread with a cover of 10-15 cm and glued with tape.
For a garage with a workshop or a room where temperature sensitive materials are stored, it is advisable to insulate the roof. As a heater, mineral wool or plates of extruded polystyrene are most often used. The thickness of the layer for the middle band should be at least 100-150 mm.
It is important to ensure a ventilation gap between the insulation and waterproofing (or between waterproofing and the roof if a membrane is used). This space allows air to circulate, removing moisture from the structure. Without ventilation, the insulation will quickly gain moisture and lose its properties, and the tree will begin to rot.
- 💧 Waterproofing is laid with sagging about 20 mm between rafters for condensate drain.
- 🌬️ The ventilation gap should be at least 40-50 mm for free air current.
- 🧱 Steam insulation (if there is insulation) is put from the side of the garage.
For the garage, it is ideal to fit the flooring with the marking of NS or H (carrying). It has a high wave and rib stiffness, which allows you to withstand the weight of a person when servicing the roof and snow loads better than the wall profile sheet C.
Water drainage system and finishing works
Organized drainage is a sign of high-quality construction. The roof slope of the attached garage is directed away from the house, so water drains from the front edge. Installation of the trough along the entire length of the cornice will collect water and take it through pipes to a storm sewer or drainage well. This will prevent soil erosion at the garage foundation.
For fastening the gutters, special brackets are used, which are mounted either on the front board or on the extreme rafters before laying the roof. The step of the brackets is 50-60 cm. It is important to ensure the slope of the gutter towards the drain pipe (2-3 mm per 1 linear meter), so that the water does not stagnate.
The final stage is the installation of wind slats on the sides of the roof and overhangs. The filing can be made with soffits (perforated panels) to ensure the flow of air into the ventilation, or boards. All metal slices and the site of damage to the coating must be painted with a special paint to prevent corrosion.
⚠️ Note: Do not use water-based bitumen mastics to seal adjoining areas in the cold. They'll lose adhesion and crack. Choose polyurethane or thiocol sealants that are resistant to UV and frost.
The main secret of the durability of the annex is not the roof material, but a properly made node adjacent to the wall of the house and the presence of an organized drain that diverts water away from the foundation.
FAQ: Frequently Asked Questions
Do I need to make a gap between the roof of the garage and the house?
Yes, the rigid connection of the roof structures of the garage and the main house is prohibited. The house and the annex can have different shrinkage, especially if the foundations are different. Adjacent should be made through a sliding connection or an elastic sealant so that when the ground moves, the roof of the garage does not damage the wall of the house or deform itself.
Can I make a flat roof on an attached garage?
Technically possible, but not recommended for a garage attached to a residential building. Flat roofing (sloping less than 3 degrees) requires the use of specific fused materials and perfect sloping. The risk of water stagnation and leaks on a flat roof is much higher, and cleaning from snow is more difficult. A single-sided roof with an angle of 10-15 degrees is more reliable and cheaper to maintain.
What waterproofing to choose for the junction of the roof and wall?
The optimal option is a combination of materials: a metal adjoining bar (fartuk) of galvanized steel with a polymer coating, wound in a sling, and a polyurethane roof sealant for filling the seam. Using only a sealant without mechanical protection (slats) will lead to its rapid destruction by the sun.
Do I need a heating drain on the roof of the garage?
If in your region heavy snowfall and frequent thaws, heating the gutter and cornice zone is desirable. This will prevent the formation of icicles and ice stoppers, which can damage the drainage system. For a garage, it is enough to lay a self-regulating heating cable in the trough and on the edge of the ramp.