Such an element of the house as an attic is a kind of challenge to standards and the destruction of the erroneous opinion that the attic is a terrible, cold and even dirty room. The attic roof can be a deliverance from prejudice if you take up its construction with your own hands.
Attics are becoming more and more popular, as only recently people have begun to realize on a large scale that this is a great opportunity to expand the usable living space of a house with a minimum investment.
The ideal option would be the layout of such a room at the stage of the building project, in which case a well-chosen type of roof will make it possible to use almost the entire attic, while the heavy roof will not overload the walls of the house.
So, how to build a mansard roof and what are the features?
Mansard roof features
For each type of mansard roofs, the following requirements are valid:
- Coating mansard roofs they are made only from light materials - metal profiles, metal tiles, etc. In rare cases, if it is necessary to preserve the ensemble of an existing building, the coating can be made of clay, cement-sand tiles and a number of other types of roofing.
- The lining of the internal partitions of the attic is made of plasterboard sheets.
- Since the attic, in comparison with the lower floors, is more susceptible to heat loss due to the extensive surface of contact of the roof with the external environment, thorough and effective roofing thermal insulation is necessary. As a thermal insulation, such a proven heater as mineral wool in the form of plates can be used. A vapor barrier layer is usually attached to the inner side of the insulation facing the room, and a waterproofing layer is usually attached to the opposite side.In addition, a ventilation space is left between the roofing and the insulation, which helps to remove warm, moist air that enters from the lower floors and penetrates through the layers of vapor and thermal insulation.
Building materials for mansard roofing
The most common, or even traditional, material for building a mansard roof truss system is wood, although attic roofing can be made from other materials.
Advice! Lumber is suitable for the manufacture of not only rafter legs, but also other structural elements - various screeds, crates and others.
A very popular material for building a roof frame is metal beams or channel bars. Roof trusses can also be made of reinforced concrete.
However, such structures have a rather large mass and require the organization of a more fortified foundation of the house.
The distance between truss trusses is designated differently in each individual project. As a rule, this distance ranges from 60-100 cm.
When using wooden rafters, the span can be up to 15 m.
You can lengthen the span using metal roof trusses that do not require the organization of additional supports. Among other things, the use of steel structures in the construction of the supporting frame of the roof has a decent number of advantages in comparison with wooden structures of a similar type.
Wooden materials are prone to aging, decay, damage by harmful insects.Steel structures are devoid of such shortcomings, but they have another predisposition - the possibility of corrosion.
Such a problem can be easily fixed with proper processing (usually just painting the metal). An additional advantage of steel rafters is their implementation in finished form. They do not require processing, but are simply assembled and strengthened at the construction site.
It can be concluded that, nevertheless, the use of a metal truss system, which has superiority over wooden and reinforced concrete prospects in almost all respects, can be considered the most high-quality and effective.
Calculation of the attic roof
By calculating area and structure mansard standard roof it is possible not only to determine the type and material for the device of the carrier system, but also to calculate the useful area of the attic, which is necessary when using the attic space as a living space.
Moreover, both the design of the attic roof and the calculation of the attic space, its useful, as well as the deaf area are carried out.
Calculations are carried out according to the following rules:
- Useful area is a zone, the distance from the ceiling bend to the floor of which is 90 cm or more. The rest of the space is considered a dead zone, which can be used, for example, as a pantry.
- The calculation of the total roof area is relatively simple. Using a ready-made roof plan, of course, if there is one, the roof is conventionally divided into geometric shapes of a simple type. Then the area of each geometric figure is calculated separately, after which the resulting values \u200b\u200bare summed up.In this way, you can determine the exact area of \u200b\u200bthe roof.
- It is also necessary to determine the most suitable roofing material for a particular case. At the same time, the choice of material for the roofing base, as well as the angle of inclination of the slope, will depend on what material the roof of the house will be covered with. The fact is that different types of roofing have different technical characteristics that affect the reliability and quality of the roof as a whole. In addition, the choice of the type of lathing system depends on the roofing material. The crate can be performed in three main ways: thinned out, solid and mixed. Each type is designed for a specific roofing. For example, ondulin and rolled materials are laid exclusively on a solid crate, while a thinned crate is more suitable for metal and piece tiles, as well as slate. At the request of a practical for each roofing material, a mixed type crate can be used. Before choosing a roofing material, it is necessary to clarify the climatic conditions characteristic of the area in which construction is underway. For example, if strong winds prevail in the construction area, in no case should light roofing materials be used, otherwise the roof may be torn off by a strong gust of wind.
In other words, in order to correctly calculate the attic roof, one should be guided by a wide range of factors that play an equally important role.
Do-it-yourself installation of a mansard roof at home
The device of the attic roof requires an understanding of its general design. As a rule, a mansard roof on a cut looks like this:
- Roof covering.
- waterproofing layer.
- Crate.
- Rafter system with insulation.
- Vapor barrier layer.
- Ceiling.
The attic truss system is arranged in the following sequence:
- Mauerlat installation.
- Installation of roof trusses.
- The device of additional fastenings between neighboring farms and within farms.
- Lathing installation.
Let's take a step-by-step look at each stage of the construction of the attic roof.
Mauerlat installation
Mauerlat installation rules:
- Mauerlat is mounted in places where the rafters are inclined. With a gable type of roof, the Mauerlat is mounted on both sides, with a four-slope - around the entire perimeter of the roof.
- The most common type of fastening of this element to the wall of the house is a monolithic pouring with concrete with studs at least 1 cm in diameter sticking out of it (about 3 cm) for docking with holes in the Mauerlat bars. The cross-sectional dimensions of the Mauerlat bars, depending on the load of the attic roof, can be 10 * 10, 15 * 15, 20 * 20 cm.
The step between the studs is calculated so that they are located between the joints of the Mauerlat with the rafters, otherwise closely spaced cuts into the rafter boards can lead to cracks.
For example, if the pitch of the rafters is 1 m, then the pitch of the studs should ideally also be 1 m, only in the center between the rafters.
- Before installing the Mauerlat, a double waterproofing layer (roofing felt or other similar materials) is laid on the studs. On the bar itself, through holes are drilled exactly opposite the studs.After laying the Mauerlat, the studs are screwed with nuts and washers of the appropriate size.
- To a brick wall, a Mauerlat beam can be attached to studs inserted into the masonry even at the stage of wall construction.
Installation of roof trusses
Further, the installation of the attic roof continues with the installation of roof trusses. Before installing the roof trusses, a template is made, according to which all other trusses are measured in the future.
To this end, it is required to climb to the top of the house, connect the boards at the required angle, attach them with a crossbar and mark for possible cutouts near the Mauerlat and the wall.
Then, on the ground, the roof trusses are assembled, and then they are lifted and mounted. First, it is necessary to mount the extreme trusses in order to install a thread level along their ridge for the rest.
The rafters are attached to the Mauerlat with studs, brackets on self-tapping screws and brackets. Between themselves, the rafters can be attached with brackets and side flat brackets to the upper corner.
With a significant thickness of the rafters (more than 20-25 cm), studs with brackets can also be used. A typical cross-section of a rafter leg is 10 * 15 or 15 * 20 cm.
After installing the trusses, it is advisable to additionally fasten them together using light boards to avoid their involuntary tilt and displacement from rain and wind.
At the end of the installation and fixing of all rafter legs, their design can be complicated to give them, in addition to rigidity, also a mansard look.
As a rule, a crossbar is installed near the upper connection of the rafter legs, which simultaneously acts as a retainer for the rafters and the basis for the ceiling of the attic room.
If an attic broken roof is provided on the roof, the crossbar is set at the “break” level.
If it is planned to install side additional walls in the attic, then an even vertical rack or an inclined brace is attached between the rafter legs and the Mauerlat.
Windows in the mansard roof can be installed either under a slope directly in the roof, or with a removal for the purpose of vertical installation.
The removal requires additional construction of the truss system, while the built-in inclined windows are arranged in the corresponding openings of the existing rafters.
This is followed by laying a vapor barrier film on the inside of the rafters, after which a heater is laid between the rafters and a waterproofing layer on top of the rafter structure. At the end of these works, a crate is mounted for laying roofing material.
Lathing device
The crate can be performed both solid and discharged. The construction of the first type is suitable for rolled roofing materials, metal tiles, soft tiles, flat slate, while the second option is suitable for natural tiles, corrugated slate, metal roofing (copper or aluminum).
If the discharged crate is easy and understandable in execution, then before installing a continuous crate, it is necessary to install a discharged one under it.
In this case, the attic roof will turn out with a double crate. Antiseptic or tongue-and-groove boards, as well as OSB boards, can be used as a continuous crate.
Advice! Soft and metal tiles can serve as the best material for a mansard roof.
If, nevertheless, you do not want to experiment with your own attic, but get a guaranteed high-quality living space, it is better to leave the installation of all elements of the installation roof to specialists.
And if, when installing a roof, it is possible, following competent recommendations, to achieve a more or less tolerable result, then the installation of inclined windows should still be entrusted to the masters.
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