Thanks to the construction of a mansard roof, it is possible to significantly increase the usable space of a low-rise private house. However, this is a very time-consuming process that requires a preliminary calculation, compliance with certain rules and techniques. Properly created truss system mansard roof is the key to creating a comfortable, reliable, functional and durable residential home.
Rafter roof system: design features
Before the construction of the attic requires a good project. The appearance of the future roof should be in harmony with the general appearance of the building. There are several types of truss frame construction, which depend on the type of roof, the step of the rafters and the variant of the mansard roof. Having stopped the choice on a concrete configuration, it is necessary to know precisely of what structural elements the rafter system consists. It is the supporting skeleton of the roof, and can withstand not only its weight, but also the effects of precipitation.
Proper installation of the truss system ensures its reliability, functionality and durability.
When you create a project attic roof should:
- perform the correct calculation of the load on the supporting bearing walls and the foundation, preventing it from exceeding;
- select high-quality insulation to avoid uneven heating of the room;
- choose a good sound insulation due to properly selected roofing materials;
- pick up a good waterproofing;
- choose lightweight facing materials for finishing the attic room.
Rafter system may have an inclined or hanging design. In hanging structures, the rafters are based on the mauerlat and ridge girder. To distribute the load on the rafters are installed lower and upper puffs. When the length of the slope is more than 4 m, to prevent sagging in the lower part of the structure, the rafter legs are supported using struts and struts. The main advantage of this design is that all its elements are placed in unused places in the attic, which creates more free space.
The inclined structure is used in houses where the bearing partition, on which the construction legs rest, is located in the middle of the building. On the internal bearing structure there is a floor plank, which plays the role of a power plate, and racks supporting the ridge girder are mounted on it. This system is used for large areas of the attic roof of a private house, the device of which can be seen in the photo. Here you can use roofing materials with high weight, such as slate or ceramic tiles.
There are projects of mansard roofs of private houses, where both versions of truss systems are used. To free space, the frame elements can be shifted to one of the sides, where they will be used as the basis for wall decoration, and the bolt is suitable for facing the ceiling. In some architectural styles, beams and racks can be used as decorative elements.
For arranging a large eaves overhang, the mansard roof is performed with an emphasis beyond the limits of the supporting walls. No power plate is installed here. The system is mounted using beams. Be sure to install the strut, special racks cut into the beams of the ceiling, and the rafters are fixed using a reliable anchor connection and wire twist.
Rafter system under the roof roof consists of the following structural elements:
- rafter legs or racks of beams;
- vertical racks;
- ridge beam;
- additional beams, regel and runs.
The basis of the whole structure of the roof is the mauerlat, which consists of square wooden beams, fastened to the external walls of the building. These boards are attached to the remaining elements of the mansard roof frame. The main purpose of the power plate is the perception and uniform distribution of the entire load from the common roof system onto the bearing walls of the building.
Rafter legs or racks of beams form the frame of the roof structure. For these elements, boards should be selected that are able to withstand the load of the roofing pie together with the outer coating. To maintain the racks of beams or truss legs, angled runs are used. Vertical racks hold the central part of the rafter bars, protecting them from bending. They also create support for the ridge bar.
In order to ensure the rigidity of the future roofing structure, a ridge beam is mounted on long truss systems. Lathing is an additional wooden structure that is attached to the roof system, and is the basis for future roofing.
Today, there are several variants of roofs of the attic type, which have a different structure of the rafter frame:
- broken lines consist of two or more slopes with different angle of inclination;
- hip have two triangular slopes on the short sides of the roof and two trapezoidal slopes with long;
- half-hinges have two short end hips over the frontal part of the roof;
- domes are characterized by a round or polygonal shape;
- vaulted are in the form of an arc.
Shed roof is the simplest option. It is often referred to when it is necessary to make an attic in a small country house. The most popular among other types of mansard roofs of private houses, the photo clearly confirms this, is a gable roof. Its design and construction with their own hands does not cause difficulties. Especially when it comes to the gable roof.
When choosing a broken roof, it is possible to get a large, functional and comfortable attic room without additional work related to the construction of walls. Today, many zealous owners of private houses prefer the truss system of a gable roof under corrugated flooring, the construction of which does not need numerous technological and technical tricks and unjustifiably high expenditure of funds for building materials.
The most difficult to install are hip, dome and vaulted mansard roofs. Their device requires a professional approach. These mansard roofs, photos of private houses clearly reflect this, have an unusual and very aesthetic design. They are characterized by a large number of pitched kinks, for which the device ends. The scheme of the truss system clearly shows the peculiarity and uniqueness of this design. The unsatisfactory condition of each of the valleys (internal corners) can carry a potential hazard to the integrity of the entire roof.
The most simple, reliable and cheap option is a shed roof mansard type. The result is an unconventionally designed building. This type of roof is used for industrial and commercial buildings. Also, often used for single-storey small private houses. All roofing materials can be used here.
The design involves the creation in the high part of the attic roof of the window. In this design there is no ridge, which simplifies its installation. Mauerlat is fixed on the walls with different levels, due to which a bevel is formed. Beams lean on it.
The angle of the slope should be in the range of 35-45 degrees. The smaller the slope, the more snow will accumulate on the roof surface, which will require the creation of additional supports and reinforcement of the supporting beams. In addition, it will significantly reduce the attic space. The design is able to withstand strong winds with the correct orientation of the roof slope, which is necessary to increase the stability of the structure.
Helpful advice! If the distance between the opposite bearing walls is not more than 4.5 m, you can not mount the supporting elements, but simply lay long wooden bars on the walls. This further reduces the cost of the construction of the roof.
This type of roofing involves the use of simple elements to create ventilation of roofing spaces. It is enough to sew two overhangs with a perforated soffit, or to mount a ventilation grill.
However, it is not necessary to choose a shed roof for narrow buildings, where it is impractical to arrange an attic floor in this way.
Duplex roof is the most common and rational solution that allows you to get a comfortable attic. Photos of houses with a mansard roof of this configuration confirm the demand for the design.
Designing and building a two-sided mansard roof doesn’t cause any difficulties. It is formed by two inclined planes (ramps), which intersect in the area of the ridge at a certain angle. Thanks to the correct choice of the optimal angle, you can create a reliable protection of the building against heavy rainfall, strong wind gusts, excessive snow pressure during heavy snowfall.
There are variations of the configuration of the roof system of dual-roof mansard roofs:
- Gable symmetric roof is a classic option, which makes it possible to evenly distribute the load on the load-bearing walls and roof support. The disadvantage of this design is the presence of sharp corners, which take the free space of the attic;
- Asymmetric roof is a non-standard design, where the ridge can move to one side. If one of the corners is more than 45 degrees, you will get a rather spacious attic room. However, in the calculations should take into account the uneven distribution of the load on the mauerlat and load-bearing walls.
- a broken roof attic has a surface of slopes, bent in the middle, forming faces that resemble two rectangles.
When the question arises how to make a mansard roof with your own hands, you should choose the most simple and practical option for further operation. Therefore, for private houses, preference is given to broken roofs.
This design allows not only to create a significant attic mansard room, but also due to the overhangs, which descend rather low, to protect the upper part of the building walls and the foundation from precipitation. In addition, it is a good solution for creating the original exterior of a private house.
Today, among the possible projects of houses with a mansard roof, you can choose the most acceptable and attractive option, and bring it to life for your own private dwelling. To make the house visually beautiful and aesthetic, you need to seriously address the issue of choosing the type of mansard roof, which should be in harmony with the building structure. Properly constructed roof truss system is capable of perfectly performing all of its operational and protective functions, which will allow you to create a warm, cozy and comfortable room.