After lofts came into fashion, that is, in fact, attics converted into housing, sloping roofs became extremely popular. This is a kind of variation on the gable roof theme, but with a slightly more complex geometry. Thanks to the arrangement of a sloping roof in your house, it becomes possible to increase the useful living volume of the attic - significantly raise the ceiling at the extreme points of the slope. In addition, according to many, such a roof looks more unusual and much more spectacular than a simple gable.
The construction of a sloping roof is somewhat more complicated than a gable, but easier than any four-slope - hip, half-hip, tent, as well as others with more exotic geometry. However, before proceeding to the study of this topic, it is recommended that you familiarize yourself with the basic terms and concepts and learn how to build simpler versions of roofs - shed and gable.
Broken roof: where to start
In construction without planning, even a dog house is not built, so the zero step in the construction of a sloping roof will be the construction of a drawing. It can be done on a computer or manually. To begin with, we build a frontal projection of the foot (the foot in short is the basis of the house without a roof) of our house. Now, also observing the proportions, we build on the drawing such a roof as we like. At the same time, do not forget that there will be an attic under it, so you need to consider the height of the ceilings in it. So we get the approximate height of the roof, the degree of slope and other parameters.
On the proposed plan the break is located at a height of 3.1 meters, which, in fact, will be (conditionally, without taking into account the roofing pie) the final height of the ceiling in the attic. If the finishing is done with drywall, then in the end the ceiling in the attic floor will be about 2.5 meters - very good. The outer angles of the slopes with the horizon are: ridge - 30 °, side - 60 °. By the way, if the slope angle is 60 ° or more, then the snow load may not be taken into account in the calculations - snow will not be retained on it. Your own drawing may have other options.
Calculation of the components of the truss system
So that our roof does not collapse under its own weight and the weight of the "roofing pie", you need to accurately select the sections of the beams and boards of the truss system, as well as calculate their maximum strength. To do this, you need to use a special program " Calculation of rafters and floor beams».
To calculate the cross section of the beams of the side slopes, you need to open the tab (they are at the bottom of the window) “Sling.1”. Next, we set a suitable section and bring in plan our house is an indicator of the vertical reaction force (in the figure in the program it is a red arrow pointing upwards) at the highest point of the rafter. Let's call this indicator Q1 kg.
When installing puff boards, we install a temporary support under each somewhere in the middle of the length. This allows you to reduce the degree of sagging. Supports 2.5×15 cm can be used (in the illustration you can see the support for only one puff). They are necessary so that during the installation of the rafters you can not be afraid that one of the bars will break, and also to prevent sagging.
We put a 2.5 × 15 board on top of the puffs, which will pull them together and make the whole structure more stable. Important: this board cannot be installed exactly in the center - it will interfere with further installation. It will be enough to retreat from the central axis about 20 cm to the right or left.
Now we put the bars of the side rafters, as shown in the illustration. Do not forget that, despite all our efforts, the geometry of the base of the roof could turn out to be by no means ideal. Therefore, first we make a template along the end beam. Then, on all subsequent rafters, we only do the top washed down. After that, we put the rafter in the place we need and only then we finally saw it down. Only after that we fix the rafters.
If the length of the beam is not enough, it can be increased, but an additional rack must be placed under the junction.
Now you can mount the plugs for the insulation material, as shown. in the illustration.
Next, you can put the rafters of the upper ridge slope. We make a temporary rack: we take a board 2.5 × 15 and put it exactly perpendicular to the extreme puff, as it is done in the illustration. The right (or left) edge of the board must be aligned exactly with the center axis. Now we take a board of the same section, apply it to our central stand and make marks with a pencil where the upper and lower cuts will be located - we got a template.
Probably the best way to increase the usable area of your own house is to replace the gable roof of the house with a mansard. In this way, one, two or even three additional rooms can be purchased without carving out additional space on the site and without getting involved in the very laborious processes of pouring a new foundation and erecting walls. And in order to find out how to make the attic correctly, you need to consider all the stages of its arrangement, starting with calculations and ending with the roofing of the roof and finishing the resulting additional premises.
In order for all work to be successful, first of all, you need to make sure that the existing walls (if the add-on will be built in the old house) are able to withstand the additional load. It will depend on this factor whether it is worth starting such a construction site, and if so, on which design of the mansard roof it would be better to stop.
It should be noted that the load on the load-bearing walls will increase significantly - due to a larger number of rafters, due to the mass of interior decoration of walls and floors, windows and doors, insulation systems, as well as all elements of the interior filling of attic rooms. All these factors indicate that you need to start with choosing the optimal attic design, with calculations, drafting and drawings of the future superstructure.
Types of attic superstructures
According to current building codes, an attic is considered to be a room under a roof that has a height from ceiling to ridge of at least 2500 mm. If this parameter is less than the specified limit, then the room is considered an ordinary attic.
- If the vertical racks that determine the height of the walls of the room are 1500 mm in size, then the attic space can be considered a full-fledged floor.
- A semi-mansard is an attic room in which there are no vertical racks, or if they have a height of 500 to 700 mm.
At the heart of any roof structure are always triangles with their “rigid” structure. There are several types of attic superstructures, but the most popular of them are high gable and broken structures. Their popularity can be explained by simpler calculations, relatively simple installation work and ease of use. In third place, after gable and broken structures, one can name a shed version of the roof, which is also sometimes used to equip the attic. Unfortunately, this type of superstructure can not be used in every house design, since it requires not only the reconstruction of the roof, but also raising the height of already built walls, which significantly increases the load on them and on the foundation.
If a new house is being built, and a second floor is planned in the form of an attic, then a shed roof option is well suited for this purpose. In addition, it will help save on roofing material.
More complex structures - domed, four-pitched, as well as with various protrusions-consoles arranged in roof slopes (single-level and multi-level), are used extremely rarely and only in exclusive projects, as they have a complex design both in engineering calculations and in installation.
The figure below the numbers shows:
1 - Gable attic.
2 - Broken attic
3 - Single-level console attic
4 - Multi-level attic.
Gable attic
attic space under d with a wuska roof, which is arranged at an angle between the slopes of 80 ÷ 90 degrees on the ridge, it may well be converted into an attic. To create full-fledged living quarters under it, it will be necessary to carry out a number of necessary reconstructions, for example, very often it is not possible without strengthening the attic floor. All these alterations and plus to this - the necessary insulation will certainly “eat up” a significant part of the usable space under the roof, so you should not expect that the rooms in such an attic will be spacious and with high ceilings.
Of course, if the dimensions (length and width) of the house are large enough, and the roof has a significant angle of inclination (45 degrees or even higher), then after the alterations it will be possible to count on a relatively spacious attic room.
broken roof
A room under a sloping mansard roof will be much more spacious and with a fairly high ceiling. Such an attic can be easily divided into two separate rooms.
The interior of the attic, made according to the "broken" type The sloping roof has four planes of slopes. They are located at different angles - the upper slopes are called ridge, and the lower ones are lateral. They, for the most part, play the role of walls.
This type of mansard roof is somewhat more difficult to design and install, but the result will please you with spacious rooms and a respectable appearance of the house.
One-level console attic
This type of attic has an even more complex design than the previous one, as it implies a displacement of the attic space to one side or the other.
Using this version of the attic device, you can get spacious rooms, much larger in area than under a gable roof.
The design of a single-level mansard roof can repeat not only a gable, but also a shed version - this will depend on how much it is supposed to take the console out of the attic and raise its ceiling.
Layered add-on
A multi-level structure is the most difficult to design and install. In its development and construction, the help of qualified specialists will definitely be needed. The supports for the levels of the attic rooms are different truss systems and ceilings, which are combined with the main one. A multi-level system involves the location of rooms at different levels of the attic, which is why the consoles should be located that way.
Having chosen the most desirable type of attic, it is necessary to determine whether it is possible to arrange it on the old walls of the house, or whether they will have to be strengthened. Therefore, it is necessary to carry out accurate calculations and draw up a project.
Roof truss basics
Most roofs, and the attic in this matter is no exception, have one of two types of truss system, or a combination of them. Each of these varieties has its own characteristics, which depend on the location of the load-bearing walls of the building.
Hanging system
The hanging truss system is determined by the fact that it is supported only by two external capital walls located along the length of the building, in which there are no internal capital partitions.
Such a system is used provided that the distance between the main supports is no more than 13 ÷ 14 meters. In any case, this design gives a fairly large load on the walls and foundation of the building.
To reduce the loads in this system, various support structures are used. elements - crossbars, grandmas, struts, puffs, racks and other details.
For example, headstocks, as it were, suspend the entire system to the ridge beam with the help of a puff, and struts pull the overlapping beams to the rafter legs.
For the attic floor in this system, it is necessary to use thick bars, logs or boards that are installed on the edge. Their thickness can be determined from the table given in this publication, based on the distance between the support points.
In order for the floor to be reliable and durable when using a hanging system, you need to carry out accurate calculations, and if it is difficult to do it yourself, then it is better
Layered construction
The layered system is distinguished by the fact that it has supports not only on external main walls, but also on internal partitions, which have a foundation under them.
Therefore, starting the construction of a house in which an attic is planned, you need to think in advance about the location of the internal capital partitions.
For a house with an attic, a layered system is the best option, since the beams overlapping the house will be firmly and securely fixed to the walls and partitions.
When erecting a broken attic roof structure, you can use a combined version of the truss system, that is, use elements of both a hanging and a layered system.
Attic design
When drawing up a project for the construction of any type of attic, it is recommended to consider it in different projections in order to visually determine the location of all supporting elements. Calculating all the parameters of the attic, they must be immediately included in the project.
Based on the calculations made, the places and methods of installation of all structural elements of the truss system are determined. The calculation is also necessary to accurately determine the materials needed for the construction of the attic and their parameters.
Structural elements
Any of the wooden structures of the mansard roof consists of certain elements that are interconnected by connecting nodes that have different configurations. To better understand the design of these connections, it is recommended to draw each of them, and when carrying out installation work, be sure to have this drawing on hand.
The design of a broken mansard roof includes the following components of the system:
- Mauerlat - element, made of a wooden beam and laid on the main walls of the building in its length. It serves to evenly distribute the load from the structure of the truss system to the wall and foundation. Rafter legs are installed and fixed on the Mauerlat. This element is mounted both in a gable and in a broken structure of the attic roof.
- Floor beams, which are laid on the main walls of the building and are the basis for the future floor of the attic and the ceiling of the first floor, as well as for the installation of the entire truss system.
- The rafter leg consists of one straight element - bar or boards in a gable type of roof, or from two parts - in a broken structure. In a broken mansard roof, the upper part fixed to the ridge is called the ridge, and the lower part, which forms the walls of the attic, is called the side. Obviously, the side leg will be installed on a layered basis, while the upper ridge rafter - usually becomes hanging
- For the ridge, a beam or board of a certain thickness is used. Sometimes they do without it, connecting the upper ridge parts of the rafter legs together, which form the ridge.
- Racks are the supporting elements of the system. They support the rafter legs and take some of the load off the walls and foundation of the building. Racks in the future will become a crate for the walls, which will be installed in the process of finishing the attic.
- Bevels or other elements installed diagonally are additional supports that hold the rafters and retaining beams together, making the system more reliable.
- Between the rafter legs for rigidity, bars are installed, called inter-rafter runs - they also give the system rigidity.
Carrying out basic attic calculations
It is quite difficult to develop a mansard roof project on your own, since this process requires certain knowledge and skills in designing and carrying out specific architectural calculations. If you make mistakes at the same time, the design of the attic will be unreliable, and besides, with its weight it can damage the walls and foundation of the building.
Everything must be taken into account in the calculations - from the beginning of construction to the finishing of the premises. However, if a not too complicated design is conceived, then you can try to cope on your own.
Skate Height Calculation
The size usable area of the attic room depends on the height of the roof ridge, and the latter is determined by the selected slope of the slopes - the smaller this angle, the lower the ceiling and, accordingly, less effective area attic space.
H=L×tgα
H- the height of the skate;
L- ½ the width of the building (if we are talking about a gable symmetrical roof);
α - the angle of inclination of the slope of the truss system.
Scheme - for clarity As an example, you can substitute the above data into the formula:
Building size 8×10 m, slope angle 30°, tangent 30°= 0.58
H \u003d 8/2 × 0.58 \u003d 2.32 m
The height of the skate will be 2,32 m.
In great detail, with all possible nuances and necessary reference tables, the process and all other parameters associated with it are described from a separate publication dedicated to this particular issue.
The area of the interior space of the attic
The technique used to determine the area of the attic space will make it possible to calculate the amount of material needed for the construction of the truss system, for insulation and decoration. Especially accurate calculations are important if the attic will be used to equip additional living rooms, as they require special design.
Usually the entire area of \u200b\u200bthe room under the roof is calculated, that is, both useful and the so-called "deaf". The living space is limited to the installed racks, which will be the basis for the installation and finishing material of the walls. The zone behind them is considered deaf, that is, most often not used.
The total area is calculated quite simply: the width of the overhangs on both sides is added to the width of the building. The resulting amount is multiplied by the length of the building.
It is also easy to find the area of \u200b\u200bliving space: for this you need to measure the width of the attic space between the racks installed under one and the other slope of the roof, and multiply the resulting parameter by the length of the attic from gable to gable.
Roofing area
To determine in advance the amount of roofing material, it is necessary to calculate the total area of \u200b\u200bthe roof slopes.
If a decision is made to install a broken or even more complex structure, it is necessary to calculate the area of \u200b\u200ball sections of the roof. To do this, you need to break it into separate geometric shapes, and then calculate the area of \u200b\u200beach of them and add the results.
For those who do not firmly remember the formulas for calculating the areas of flat figures, a "cheat sheet" scheme is given.
Shed roof area
If the attic roof is pitched, then its area can be calculated using the formula: Sabcd = Lcd × Lbd.
The area of one slope - there is nothing easier Pay attention to the drawing. When calculating, not only the length and width of the roof structure of the slope are taken into account - we must not forget about the cornice overhangs from all sides.
gable roof
With a symmetrical arrangement of roof slopes, for calculating a gable roof, it remains only to multiply the value obtained above by two.
For example, take the same example as discussed above. The size of the building is 10×8 m. The angle of the slope is 30 °, the height of the ridge H = 2.32 m. It is easy to determine the length of the rafter - S
S = H / sin α = 2.32 / 0.5 = 4.64 m
We accept cornice overhang 0,7 m, gable overhang 0,7 m. According to the shed roof formula, the area of \u200b\u200bone slope is calculated.
(10 + 2 × 0.7) × (4.64 + 0.7) = 60.88 m²
Then, to get the total area of the two slopes, the resulting result is multiplied by two.
Q = 121.76 m²
This technique is designed to calculate the continuous surface of slopes, excluding windows, ventilation channels and a chimney.
If the roof has a very complex structure, then it is better not to take risks and still seek the help of professionals who will make the necessary calculations using special computer applications.
When using slate, soft roofing, other profile materials, you can use a simplified calculation formula.
Starting from the drawing:
So, the following formula is applicable for calculation:
Q\u003d K × (B + 2A) × (L + 2C)
Q- the required amount of roofing;
AT — the width of the building (along the gable wall);
BUT- the width of the planned eaves of the roof;
L- total length of the building;
C- the width of the side overhangs of the roof.
To is a coefficient that takes into account the angle of inclination of the slope with respect to the horizon (α). By and large, it is a trigonometric function of secant (sec), equal to the reciprocal of cosα.
In order not to delve into the theory, it is easier to give a coefficient table To in absolute, that is, numerical measurement:
| Tilt angle, degrees | K factor | Tilt angle, degrees | K factor | Tilt angle, degrees | K factor | Tilt angle, degrees | K factor |
|---|---|---|---|---|---|---|---|
| 1 | 1.0002 | 18 | 1.0515 | 36 | 1.2361 | 53 | 1.6616 |
| 2 | 1.0006 | 19 | 1.0576 | 37 | 1.2521 | 54 | 1.7013 |
| 3 | 1.0014 | 20 | 1.0642 | 38 | 1.2690 | 55 | 1.7434 |
| 4 | 1.0024 | 21 | 1.0711 | 39 | 1.2868 | 56 | 1.7883 |
| 5 | 1.0038 | 22 | 1.0785 | 40 | 1.3054 | 57 | 1.8361 |
| 6 | 1.0055 | 23 | 1.0864 | 41 | 1.3250 | 58 | 1.8871 |
| 7 | 1.0075 | 24 | 1.0946 | 42 | 1.3456 | 59 | 1.9416 |
| 8 | 1.0098 | 25 | 1.1034 | 43 | 1.3673 | 60 | 2.0000 |
| 9 | 1.0125 | 26 | 1.1126 | 44 | 1.3902 | 61 | 2.0627 |
| 10 | 1.0154 | 27 | 1.1223 | 45 | 1.4142 | 62 | 2.1301 |
| 11 | 1.0187 | 28 | 1.1326 | 46 | 1.4396 | 63 | 2.2027 |
| 12 | 1.0223 | 29 | 1.1434 | 47 | 1.4663 | 64 | 2.2812 |
| 13 | 1.0263 | 30 | 1.1547 | 48 | 1.4945 | 65 | 2.3662 |
| 14 | 1.0306 | 31 | 1.1666 | 49 | 1.5243 | 66 | 2.4586 |
| 15 | 1.0353 | 32 | 1.1792 | 50 | 1.5557 | 67 | 2.5593 |
| 16 | 1.0403 | 33 | 1.1924 | 51 | 1.5890 | 68 | 2.6695 |
| 17 | 1.0457 | 34 | 1.2062 | 52 | 1.6243 | 69 | 2.7904 |
| 35 | 1.2208 | 70 | 2.9238 |
Let's go back to our example:
Q= 1.1547 × (8 + 2 × 0.7) × (10+2 × 0.7) = 123.74 m²
With considering overlaps slate sheets - it turns out almost the same as in calculations carried out by a different method. Of course, on the advice of experienced builders, another 10 ÷ 15 %
(The figure shows a gable roof, however, the formula is fully suitable for calculations with the required level of accuracy for shed or hip roofs. True, with a caveat - at the hip roof, the steepness of the main and side slopes must match. If not, then the calculation is carried out for each pairs of rays separately, and then the value is summed).
Total weight from truss system and roofing
It is equally important to correctly choose the optimal material for roofing and correctly make a crate for it. This calculation is carried out taking into account the length of the rafters and the angle of their slope.
The crate for roofing material can be sparse, mixed or solid. For example, a metal tile, corrugated board or slate is fixed to a sparse crate, and a soft roof - only to a solid one.
When choosing a roof, you need to get information about its operational characteristics. It is from them that the durability and reliability of the roof structure will depend. Roofing material must also be selected taking into account the specific region and its climatic conditions, especially factors such as temperature changes and strong winds.
An important factor is the weight of the roofing, especially if the mansard roof is installed on old walls. Therefore, you should estimate the weight of the roof in advance and find out how much the load on the building structure will increase, and whether it will be acceptable.
| Roofing material for mansard roof | Roof slope | Material weight kg / m² |
|---|---|---|
| Asbestos cement slate sheets with medium profile | 1:10 to 1:2 | 11 |
| Slate with reinforced profile | 1:5 to 1:1 | 13 |
| bituminous tiles | From 1:10 and more | 6 - 8 |
| Soft roofing, taking into account the continuous lathing | From 1:10 and more | 9 - 15 |
| Galvanized metal sheets with single seam | From 1:4 and more | 3 - 6,5 |
| With double folds | From 1:5 and more | 3 - 6,5 |
| Ceramic tiles | 1:5 to 1:0.5 | 50 - 60 |
| Cement-sand tiles | 1:5 to 1:0.5 | 45 - 70 |
| metal tile | From 1:5 and more | 5 - 7 |
| Ondulin | From 1:10 and more | 3 - 3,5 |
Most often, soft roofing or ondulin is used to cover attics, since these materials are one of those that have the lightest weight and are easy to install.
For example, you can calculate the weight of 1 square meter of roofing, where ondulin is used for coating, taking into account the crate and insulation - sprayed polyurethane foam. To do this, you need to find the sum of the weight of each of the materials and multiply by a factor of 1.1 (this factor takes into account the overlap on adjacent sheets of roofing material).
- The weight from a flat crate, 20 mm thick (plywood or OSB) is 14 kg / m².
- Insulation - polyurethane foam, 100 mm thick, has an average weight of 3 kg / m²
- The average weight of ondulin is 3.3 kg / m²
We get in total:
(14 + 3 + 3.3) × 1.1=22.3kg /m²
To calculate the total weight load of the roof on the walls, you need to multiply the weight of one square meter by the area of \u200b\u200bthe entire coating. In our example, this will work:
M = 123.74 × 22.3 = 2751.82 kg.
A lot - almost 3 tons gives only a very light roofing with a crate and also a very light type of insulation.
But that's not all! The roof is affected by snow loads in the winter, plus wind pressure, all year round. These parameters are also necessarily taken into account when calculating the necessary wooden structural elements of the truss system and floor beams, and when taking into account the total load of the roof structure on the walls and foundation of the building.
- Then, the whole system is closed with a vapor barrier film, which is fixed on the logs with brackets.
- Boards or plywood sheets can be laid on top of it.
- A decorative coating is laid on them - it can be linoleum, laminate, parquet board and other materials.
Additional insulation can be created by laying an electric cable or infrared warm floor under the decorative coating. It is better to read about these possibilities separately in the article devoted to
- If the floor is mounted on floor beams, you will have to work from the side of the first floor.
- From the side of the lower room, boards are mounted on the floor beams. It is desirable that they be even, you can even use a floorboard for the subfloor.
- After that, a vapor barrier film is laid on these boards from the side of the attic, which will cover not only the subfloor, but also the floor beams.
- On top of it, another layer of vapor barrier is laid and attached to the beams.
- Then, logs are fixed to this coating perpendicular to the beams.
- Another layer of insulation is mounted between the lags, it is better to choose mineral wool for it, since, when straightened, it is tightly installed between the bars, leaving no voids.
- Then it should also be covered with vapor barrier material.
If it is decided to cover the floor with one of the decorative coatings, then plywood sheets are laid on top of the log, and then laminate, linoleum or other materials are laid on them. Again, nothing prevents in this case from using, for example, film floor heating.
Installation of insulation on the walls and ceiling of the attic
Having finished the installation of the floor, you can proceed to the installation of insulation on the walls.
- If material in mats is chosen for this process, then before laying it, sheets of vapor barrier material are fixed on the rafters.
It is fixed in such a way as to close the entire space and deepen it between the rafters.
If the vapor barrier is fixed on the other side of the rafters, then the mats will independently hold between two wooden surfaces.
- If one of the is selected, then it is not necessary to fix the vapor barrier film under it. It will be enough waterproofing, which is laid on the rafters outside the structure.
Spraying polyurethane foam - quickly and efficiently, but requires special equipment and work skills To use this insulation technology, you must have special technological equipment, or you will have to invite a specialist who will do the work in one day. It is not easy to carry out this operation on your own without experience - in order to do the work without harming your health, you need to know the process technology and have the necessary protective equipment.
After carrying out insulation work, wall cladding is carried out.
Prices for popular types of heaters
insulation
Attic wall decoration
Before you start finishing the walls, you need to resolve the issue of electrical wiring, the cable of which must be well insulated with double-layer corrugated pipes.
After the wiring of the electrical cable is done, you can safely proceed with the installation of the finishing material.
For decoration, they usually use wooden lining, drywall or plywood with a beautiful textured pattern.
For any of these materials, it is desirable to make a crate of slats on the rafter legs and vertical racks with a section size of approximately 20 × 70 mm. These guides are fixed in increments of 500 ÷ 600 mm. In addition to the fact that the crate of the slats becomes the basis for fixing the finish, it also forms a ventilation gap between the finishing material and the vapor barrier.
- made quite simply. It leaves walls smooth and neat, ready for painting, traditional wallpapering or even liquid wallpapering.
Therefore, drywall finishing should be chosen by those homeowners who like to often change the interior design of the premises.
- Clapboard wall decoration is a longer and more laborious process than. For such a sheathing, a crate with the above parameters is also perfect. The only thing to think about is the direction of the lining boards, that is, it should be located vertically with the horizontal orientation of the crate and vice versa.
If desired, after installation, the wood can be varnished with a water-based varnish or give it a deeper color using a stain.
Wood is an amazing material that can create a special atmosphere in the room with the aroma of the forest, which has a positive effect on the structure and well-being of the residents. That is why natural lining is very often chosen for flooring, walls and attic ceilings.
Video: insulation of the attic room and finishing it with clapboard
- You can come up with a beautiful plywood finish. But that's only if it will not be covered with paint on top, then you need to choose a quality material that has a beautiful natural pattern. Plywood is mounted much faster than lining, and makes the walls even, covering large surfaces at once.
This material can be covered with varnish, paint or any kind of wallpaper, but you can leave the walls in their natural state only by carefully cleaning possible defects in the form of protruding splinters or burrs.
The construction of an attic is a rather laborious and complex process that requires high experience in the construction craft. If there is no one to understand about the above technological operations, then you should not take it on your own - it is better to invite professional masters to perform the work. They will save you from unnecessary problems and build an attic according to the project conceived by the owner of the house.
Video: an example of the construction and decoration of the attic
broken roof- this is essentially a kind of gable roof. Most often, people choose this design when they want to get more living space on the attic floor. And someone just visually likes this form more than the usual gable.
This article will describe the sequence of erecting a sloping roof when the rafters are supported on the floor beams. Further, I will often refer to previously published articles and. Therefore, I recommend that you first familiarize yourself with their content, if you have not already done so.
So, we start by taking a piece of paper (preferably in a box) and drawing on it the foot of our house with the obligatory observance of scale. Anyone who can draw on a computer is great. Now, based on our personal preferences, we draw (also on a scale) the future roof. At this stage, you need to decide on the height of the structure, with the angles of inclination of the slopes and with the location and size of the window openings.
As an approximate recommendation, I can give you a diagram with proportions that I usually use in my practice. In the figure, the height of the break location of 3.1 meters allows you to ultimately get the final height of the ceilings on the attic floor (with plasterboard trim on the frame) of at least 2.5 meters. The angles of inclination of the side slopes and the upper ones are approximately 60 ° and 30 °, respectively. By the way, the angle of inclination of 60 ° allows you to ignore the snow load when calculating the rafters of the side slopes. All these dimensions are optional and you can adjust them at your discretion.
Now we need to select the sections of the elements of the truss system and calculate them for strength. For this we use the program that we talked about in the article. We calculate the rafters of the side slopes in the tab “Sling. 1″ Having chosen a suitable section, you must also write out from the diagram the value of the vertical reaction force (red arrow up) at the top of the rafter. Let it be "Q1, kg".
We calculate the rafters of the upper slopes in the "Arch" tab. On the schematic, first of all, specifying the value of L, we substitute the value of h0 equal to h. Having selected the section of the rafters, we also write out the value of the vertical reaction force from the diagram, but already at the lowest point of the rafter. It will be designated "Q, kg".
Adding the values of Q1 and Q, we get the concentrated load N, which is transmitted through the racks to the floor beams. We use it when choosing the section of racks and floor beams.
Having decided on all the dimensions, we proceed to the direct construction of a sloping roof. As an example, let's again take a box of a house measuring 8x8 meters:
Step 1:
We install the Mauerlat and floor beams. The details of this process have already been described in the article, so I will not repeat myself. The cross section of the floor beams according to the calculation is 100x200 mm.
Step 2:
We expose the racks along two lines (strictly vertically), first the outer ones from the bar 100x150 mm, then pulling the laces - intermediate ones, with a section of 50x150. The distance between them is no more than 3 meters. We fix all racks with temporary struts. In order not to clutter up the drawing, I showed the spacers on only one rack. We take the height of the racks 10 cm more than the desired height of the finishing ceilings in the rooms.
Now I want to make one important remark. It often happens, especially when a new roof is being made on an old house, that by expanding the floor beams when looking at them from above, we will not get a strict rectangle. The house may be slightly narrowed in any direction. This is not scary, but to facilitate the work, you need to put the racks so that a rectangle is sure to turn out of them. This will allow us to make all the rafters of the upper slopes according to one template. Otherwise, the rafters will have to be placed along the cord and cut in place, and this takes a lot of time and effort.
Step 3:
We put runs from a 50x150 mm board on top of the racks and install the remaining missing racks also with a section of 50x150 mm. No more spacers are needed. The resulting structures will play the role of the frame of the future side walls of the attic room.
Step 4:
We install and fasten on the runs, for example, with the help of roofing corners, puffs (crossbars). Their cross section for this example (the length of the puffs is 5.5 meters), I calculated according to our program in the “Beam” tab in the “Distributed load” plate. At the same time, “Load (normal)” and “Load (calc.)” were taken equal to 150 kg/m². There is no operational load on them.
The calculation showed that with a section width of puffs of 50 mm, the section height should be at least 210 mm. But I still took boards with a section of 50x200 mm. We will eliminate the unacceptable deflection by installing hangers (see below). Of course, this will give an additional load on the rafters of the upper slopes, and therefore, we will increase the cross-sectional dimensions of the rafters of the upper slopes obtained during the calculation from 50x150 mm to 50x200 mm.
When installing puffs (crossbars), we put a temporary support under each of them approximately in the middle of the span. In this case, the resulting sagging can be reduced. It is enough to use an inch 25x150 (only one such support is shown in the figure). They are needed so that when installing the rafters of the upper slopes, calmly walk on puffs, without fear that they will break, and, as I said, to reduce sagging.
Having installed all the puffs, we fasten them on top with a board (25x150 mm). The structure will become more rigid. Do not place this board strictly in the middle. Step back from the axis in any direction by about 20 cm. Why, it will be clear later.
Step 5:
We install the side rafters (left figure). This is done in the same way as described in the article on the gable roof. We also prepare a template, make the upper washed down, mark the lower washed down in place and fasten the rafters.
We install plugs for insulation (right figure). By the way, when I wrote about the gable roof, I completely forgot about them.
Step 6:
We begin the installation of the rafters of the upper slopes.
To begin with, we make a rafter template. To do this, take a suitable piece of board 25x150 and temporarily fix it strictly vertically on the extreme crossbar according to the figure. One of the upper corners of this board (for example, like my right one) should coincide with the geometric center of the roof, i.e. the right side of the board coincides with the axis of the roof (dashed line in the figure). Now we take a suitable board (also an inch, to make it easier), apply it and draw the lower and upper cuts with a pencil.
We make two rafters according to the template and install them. Three people need to work. We do not use a ridge beam here. Having installed the first pair of rafters, we fix it with a brace so that it does not fall.
Next, we put all the other rafters. On a roof like ours (length 8 meters), it will be enough to install four struts, two in different directions. The remaining pairs of rafters, while there is no crate, are temporarily fastened with an inch board (see figure).
Step 7:
According to the picture we sew pendants (board 25x150). They will prevent the puffs (crossbars) from sagging when we remove the temporary props. Now we see why we didn’t put the board fastening all the puffs strictly in the middle. Otherwise, she would be in the way now.
Step 8:
We install the gable frame and sheathe it.
After that, we make cornices, lathing, gable overhangs and gable ebbs. How to do all this, read the article about the gable roof. Again, I will not paint everything over again.
I hope this article will be useful for someone.
With the help of the attic, you can not only increase the number of usable rooms. A building with a high roof slope looks more solid and presentable, while its construction is less expensive than the construction of a full-fledged two-story building. How to make a mansard roof with your own hands, read this article.
Choosing the type of roof and truss system
For the arrangement of the attic, two types of roofs are most often used:ordinary gable: the roof has two inclined slopes, its ends are closed by triangular walls - gables;
broken line: each of the slopes is additionally divided into two more, located at a different angle; while the angle of inclination of the upper is much smaller; the ends (pediments) have the shape of a pentagon.
Sloping and gable roofs
Building a gable roof is certainly much easier. But the attic rooms in it, unfortunately, will be cramped, and the ceilings will be too low. Therefore, for arranging a comfortable attic, broken gable roofs with a small (40-45 °) slope angle are more often used. Moreover, the smaller this angle, the more spacious the attic rooms will be. However, when erecting a more complex broken structure, it will be necessary to make additional connections between the rafters (inclined beams that serve as the roof frame).
There are two types of truss systems:
layered: rafters rest only on the outer walls;
hanging: additionally rely on capital partitions.
The first option is used only in the absence of such partitions. But, since the load on the load-bearing walls in this case is quite high, it is possible to build layered structures only with a distance between the main walls of up to 8 m. In other cases, it is better to use more durable hanging structures.
Overhead and hanging truss systems
On broken mansard roofs, they are most often mounted combined systems, in which the rafters coming from the ridge are made hanging, and the lower side rafters are layered. Such a device is especially effective for roofs with a slight slope.
Combined truss system
Gable sloping roof frame
To get a full-fledged attic with a ceiling height of 2.5 m roof height before breaking should be equal to 3.1 m. Recommended tilt angles- 60 and 30 ° (it is allowed to tilt the upper part of the rafters 15-45 °).
Mauerlat device
Mauerlat- the lower roof support, laid on the upper part of the load-bearing external walls:1. When installing a gable roof, the Mauerlat is attached on both sides of the building at the locations of the rafters. Thanks to him, the load from the weight of the roof is evenly distributed over the entire surface of the wall. With a small mass of the roof, it is allowed to lay it only under the rafters, but in our case it should be laid along the entire perimeter of the wall.
Mauerlat mount
2. For the manufacture of Mauerlat, a bar is used coniferous wood 100×150 mm. So that the tree does not rot, it is better to separate it from the wall. waterproofing layer. For these purposes, roofing material or bitumen is most often used.
Mauerlat waterproofing
3. Mauerlat is attached to the base with threaded studs for a wide washer. To do this, holes are drilled in it exactly the size of the fasteners. At the same time, their frequency should not be less than the number of rafter legs, but no more than 2 m.
4. In brick walls, it is attached to wooden plugs. To strengthen the fastening of the Mauerlat in the masonry, it is possible to provide special pockets where it will be placed. It is allowed to bookmark a special masonry wire (rolled wire), with which the Mauerlat is screwed to the base. During the construction of buildings made of aerated concrete or concrete slabs in the walls, an armored belt with inserted thick metal studs is provided for it. Their length should be enough to girth the Mauerlat and tighten the locknut.
5. in wooden buildings as a Mauerlat, the upper log of a log house or timber is used.
In wooden houses, the top log of a log house can serve as a maeurlat
Installation of runs and struts
The most common way to build a mansard roof is the following algorithm:1. Mauerlats are laid first.
2. For ease of movement on the roof, a temporary flooring is being prepared to replace scaffolding.
Installation of a U-shaped frame for the roof
Terms used in construction
Runs are called additional horizontal beams. They may be:
skating: the upper part of the rafters rests on such a run; they may not be used in broken mansard roofs;
lateral: are evenly distributed along the entire slope of the roof, their number can be different and depends on the size of the roof itself and its angle of inclination.
4. Rafters made of durable timber 50×150 mm. Additional rigidity to the rafter legs is given with the help of braces(diagonal beams that serve to reinforce the structure, installed at an angle of 45 °, sometimes they are called rafter legs).
Rafter leg attachment
There are two types of fastening rafters:tough: on metal staples, bolts or with a combination of wire and nails;
sliding (articulated): in the case of house movement, the rafters move along the Mauerlat along the "sled" provided in the mounts.
Rigid connection of rafters
The hinged version is more reliable, as it allows you to avoid displacement or even rupture of roof elements during seasonal ground movements. When erecting wooden houses subject to shrinkage, such fastening also helps the roof to “adjust” to the new position of the walls.
Articulated rafter legs
Types of rafter fastenings
Advice. To determine the location of the upper rafters, a temporary rack should be made from several beams and nailed to the Mauerlat so that the upper part falls exactly on the center line of the roof. On it, you can easily align the upper rafters.
The upper part of the Mauerlat should be bevelled. To avoid mistakes, it is better to make a template from a thinner board, which is applied to the run and a washed down shape is drawn on it. If the lower part of the rafters is attached to the cuts, they are cut out already in place.
Watch a video on how to make a mansard roof with your own hands:
The attic is not only a beautiful appearance of the house, but also a real opportunity to increase living meters, to use all the space under the roof of the house in the most practical and functional way. The most relevant is the installation of a mansard roof in individual private construction, in a country house or in the country.
In order for the building to be reliable and safe, not to collapse under additional loads, you should choose the right type of roof, calculate the slope, size, materials.
In the article, we will analyze in detail how a mansard roof is built with our own hands, we will dwell on construction technologies and structural features.
Types of mansard roofs
Today it is difficult to surprise with architectural delights in private buildings, people strive for the comfort and aesthetics of their homes. The design of the attic is striking in scope: high and low, broken and ordinary pitched, turrets and domes, complex multi-level and most ordinary mansard roofs crown the buildings, giving each one its own unique individual style.
Shed mansard roof the simplest in design, it is supported by a truss system, or truss, on external load-bearing walls located at different levels. Typically, such roofs are arranged during the construction of attics on small country houses, verandas.
Gable or gabled mansard roof- a classic design, which is erected using inclined or hanging rafters. The slope angles of the slopes can be uniform or uneven.
The hip roof is a four-pitched structure that does not have gables. Two large slopes - trapezoids, slopes from the end walls - triangles-hips. Half-hipped roofs are roofs that have trapeziums on the sides, and a vertical wall comes first from the fronts, and it is cut off at an angle to the ridge.
Hipped mansard roof- it's almost hip, but all the slopes are isosceles triangles that meet at one point. This design is symmetrical and has no ridge, suitable for square buildings.
- this is, in fact, a combination of several gable roofs. The design is arranged on houses with complex geometry, with kinks and a polygonal base. Such a roof has many ribs and slopes, therefore it requires complex calculations and professional skills; making such a roof with your own hands is a very difficult task.
A sloping roof is a classic of the attic structure, the shape of the attic roof allows you to significantly increase the usable area and equip a full-fledged living room, bedroom, nursery, study, etc. inside. stingrays. The design of the roofing system of the attic is complicated to the farm, the slopes consist of two rafters, reinforced with racks and reinforced at the break points with stretch marks. The lower belt of the truss is also the basis of the floor.
Vaulted, conical, domed attic roofs are used in elite private housing construction, the design of such attics impresses with its delights. The truss structure of such attic floors is quite complex and is made of materials that can be bent.
When combining several types of roofs, complex and unusually spectacular, beautiful attic structures are obtained. Such an unconventional approach to the design of a mansard roof is necessary if the house has a complex shape: with ledges, height differences, and additions. Despite the aesthetics and bewitching appearance, complex mansard roofs have significant drawbacks - this is a lot of internal corners (valley) with a small slope, pitched breaks, which are a risk zone for the integrity of the roof, and cause leaks and snow gathering. The calculation of this type of mansard roof requires special skills and knowledge, if you intend to make such an attic roof with your own hands, try to minimize the presence of complex elements.
Mansard roof, photos of the main types of floors applicable in individual construction: 1. Single-pitched 2. Double-pitched 3. Multi-pitch 4. Hip 5. Sub-hip 6. Hipped 7. Vaulted 8. Conical 9. Dome 10. Classic mansard sloping roof
A simple gable or sloping attic roof will not produce the same effect as a combined one, but such a mansard roof design is much more reliable, it can be calculated and built with your own hands. The choice of the type of mansard roof depends on the architectural design and plan of the house, on the slope of the slopes laid down in the project, the characteristics of the supporting structure and the choice of materials for the roof.
Mansard roof calculation, slope angle and choice of materials
Note that the roofing materials and the scheme of their installation affect the slope of the attic slopes, but mainly the slopes depend on the geography of construction. In snowy regions, steep roofs with a small overhang should be arranged; in southern and almost snowless regions, a small slope and a larger overhang can be made. If there are strong gusts of wind in the region, then the roof should be flat, which will reduce the windage of the roof.
The standard scheme of the mansard roof, this arrangement of rafters allows you to make the most of the area of the attic floor
Thus, the calculation of the slope of the mansard roof is based on the starting points:
- the desired height of the attic interior;
- architectural solution;
- in what climate zone the object is located;
- what roofing material will be used.
It is optimal if the gable roof of the attic is tilted by 45 ° and above, and the classic broken mansard roof with its own hands has a slope of the lower slopes of 60 °, the upper 30 °. Such slopes allow you to create a comfortable room for living inside, if you correctly think over the interior of the attic.
Roofs of houses with an attic, photos of the advantages and disadvantages of the interior space with different types of roofs
Do-it-yourself classic broken mansard roof, in addition to rafters, includes racks, struts, puffs, suspensions in the design. The size of the section of structural elements is calculated when calculating the truss system.
How to build a mansard roof, the optimal proportions of the roof relative to the width of the house
Important: The angle of inclination of the roof slope of 60 ° allows you to neglect the loads from precipitation. The greater the slope of the truss structure, the longer the rafters and the larger the roof area, but the less useful internal area.The maximum load from precipitation on the roof is achieved with a roof slope of 30 °, at 45 ° rain and snow do not linger.
Table, how the choice of roofing material depends on the angle of inclination of the slopes of the mansard roof
- the width of the end (pediment) is 10 m, we divide it in half: 8/2=4;
- the optimal roof height in the ridge is 2.4 m.
Here we need a school geometry course: The sine of an angle in a right triangle is equal to the ratio of the adjacent leg to the opposite leg:
Sin B \u003d 4 / 2.4 \u003d 1.67
We open the Bradis table and see that this value of the sine corresponds to an angle of approximately 59 o, we round the value. Thus, our desired slope angle is approximately 60 o.
Mansard roof construction technology
A broken mansard roof, the drawings of which are presented in the article, is the most popular type of attic floor construction for a private developer, so we will analyze the key stages of its construction. Standard mansard roof designs do not require additional calculations, which greatly facilitates installation and reduces financial costs for the manufacture of an individual project.
Mansard roof frame, diagram of the main structural elements
Before you make a mansard roof, a special support bar is laid around the perimeter. If the house is wooden, a beam or a log, then the upper crown of the walls will serve as a Mauerlat. In a brick, stone, monolithic concrete or foam concrete house, a layer of waterproofing is laid along the perimeter (2 layers of roofing material, bitumen-polymer mastics), a wooden bar - Mauerlat is installed flush with the inside of the load-bearing walls, which allows you to evenly distribute the load from the roof and precipitation on the base and along all supporting structures. Outside, the mauerlat is laid with facing material, it should be visible that 30 mm of timber should remain so that the loads fall solely on the timber, and not on the lining.
Scheme of installation and fastening of the Mauerlat and rafters
Advice: the timber for the Mauerlat should be with a cross section of 100 * 100 or 150 * 150 mm.Then we install the floor beams, first we lay the timber along the edges, check the correctness of the geometry with a level, and attach it. We stretch the cord along the upper plane and install the remaining beams at a distance of 500-600 mm from each other. If there is not enough height to the desired level, then we put the slats, if on the contrary, then we squeeze the Mauerlat. The removal of the beams sets the width of the cornice, usually 300-500 mm. Next, we install short beams with a step of 1000 mm for the front ebb device.
Advice: Fasteners to the Mauerlat can be 150 nails, rafter corners for self-tapping screws.Installing the frame
To install the skeleton, we expose the vertical rack-beams along the plumb line or level and fix it on temporary struts. First, we install the extreme ones, in the corners, pull the cord and set the middle ones in increments of no more than 3 m.
The height of the racks depends on the shape of the roof provided by the project, usually it is equal to the distance from the ground to the mauerlat (height of 1 floor) or +100 mm from the desired height of the finished ceiling. We tighten the racks from above with girders - boards 150 * 50 mm.
Construction of a mansard roof, how to properly install a side run
On the girders with the help of roofing corners we fasten crossbars-puffs - in the attic roof these are bars that connect the side girders, with a cross section of 200 * 50 mm. The deflection of the puffs is eliminated with the help of the subsequent suspension device to the rafters, and until the rafter system is installed, it is recommended to install temporary supports.
Installation of a mansard roof, puffs from above are fastened with a board, which gives the structure rigidity
truss system
First you need to make a template from boards 20x150 mm: we apply the board to the Mauerlat and to the side run, make notes, saw off, and the template is ready. Since buildings often have errors in geometry, it is better to make a wash down along the upper run, and to cut down the Mauerlat in place.
Mansard roof, installation of side rafters
If the length of the slope is longer than the standard 6-meter board, then it is recommended to order special lumber for your measurements. But if this is not possible, then the boards are spliced, for this a piece of board 1.5-2.0 m long is sewn from below, but a rack will have to be installed under it.
The rafters are attached to the side run with three nails, to the Mauerlat on metal plates, self-tapping screws and nails, or on brackets.
Attic roof, do-it-yourself installation of side rafters, fastening methods
We make a template for the upper rafters. We take the board and fix it on the extreme crossbar in the middle, strictly vertically, one edge of the board should coincide with the central axis of the mansard roof. We apply the beam, draw the lower and upper washed down.
Gable roof attic, how to make a template for the upper slopes
On the ground, we cut out the template, make the left and right rafters and mount them on the roof. A ridge beam is not used on a mansard sloping roof, so the rafters are attached with a strut. By the same principle, we install the rest of the upper truss system.
How to properly build a mansard roof, install struts (top) and install the top slope
Hanging rafters are a triangle - the simplest truss, but this design does not transfer expansion loads to load-bearing walls, so puffs should be installed.
Mansard roof frame, methods for installing puffs on hanging rafters
After the installation of the truss system, a gable (end) frame is installed and sheathed, the structure is reinforced in places where windows will be installed. Then the crate, cornice, overhangs and ebbs are made.
Four-pitched mansard roof, installation of gables
Rest of the way
A vapor barrier membrane is laid along the rafters, which is pressed by a counter-lattice of 40 * 20 mm, 50 * 50 mm rails, additionally creating a gap for ventilation. The crate, depending on the material for the roof, can be solid or indented. Next, waterproofing is laid, on which the roofing material is laid.
The attic should be insulated from the inside, the heat-insulating layer is additionally covered with a vapor barrier to protect the insulation from condensation. Then you can finish the room with the selected facing material.
Be sure to see how the mansard roof is built with your own hands, the video will help you understand the key stages in the construction of the attic floor.
