Many private households become much more attractive if a gable roof with an attic is added to the project. It's not a bad idea to use the free space under the roof. You will receive not only the design and architectural appeal of the house, but also additional rooms for living. But the drafting of the project is also fraught with many problems - for example, you need to correctly calculate the roof and choose a convenient device. It is about how to make an attic with a gable roof, we will tell in our article. But let's also touch on the broken construction a little, since it is one of the most common.
Features of the roof with an attic
Attic is a building in which people live. Its purpose, frankly, is specific. Therefore, the roof will have the following features:
- The shape of the roofing system willspecial, it is very different from the "classic".
- The roof has a lot of windows.
- A full-fledged heat-insulating layer is being arranged, which allows for comfortable living for people inside.
- You will definitely have to lay internal communications in the attic floor.
In the article we will present projects of houses with a gable roof and an attic, which are most often used by people during construction. But you should always remember that, in addition to standard projects, there are individual ones - you can always order them from an architect, but you will have to pay a certain amount.
Roof truss construction
The most important element of the attic is the roof structure. If you do it right, you can not only correctly implement the arrangement of the attic, but also ensure the normal operation of the whole house. If you focus on practice, you can equip the attic floor in any version of the roof. In the article, we have given photos of houses with a gable roof with an attic. You can also see the broken structure of the roof and see the differences between the two systems.
Depending on what kind of building project, you can even use a shed roof structure. It is also allowed to use hip or multi-panel roofs. In other words, it all depends on your capabilities, desires and project. Nevertheless, it is worth noting that the design of a broken rafter system has a number of advantages - it allows you to increase the free space under the roof due to the fact thatthat the tilt angle changes.
This option would be almost ideal, unless you take into account the high costs of construction. Increases, and significantly, the consumption of materials. But it is impossible not to mention that it is technically more difficult to make such a roof than a simple gable one. Its design contains the following elements:
- Riding and side rafters.
- Riding and side rafters.
- Braces.
- Racks.
Rafters are hanging and inclined. The latter are used if the project contains intermediate load-bearing walls. In other words, one of the sides of the rafters should rest against the Mauerlat along the outer, and the second along the inner wall. As for hanging rafters, they have two tiers - lower (side) and upper (ridge). In order to give rigidity to the structure, racks and jumpers are installed.
Where to start building a mansard roof?
It should be noted right away that the calculation of the attic under a gable roof is the first step that must be completed before starting work. Usually the construction of the attic is included in the overall work plan. But sometimes homeowners change the roof and at this stage they realize that they want something more from their home.
For example, increasing living space. In order to properly organize construction work, you need to develop a drawing and plan. And then you need to strictly follow these documents. Let's start from the very beginning - with the calculationattic.
How to calculate the parameters of the attic floor
It is necessary to adhere to a certain sequence when calculating a gable truss roof with an attic. The rules are as follows:
- In the first step, you need to choose a truss scheme.
- Now you need to calculate the parameters of the attic room.
- Calculate the amount of materials and maximum allowable loads.
- Create a detailed construction plan.
It is imperative to approach all calculations very carefully so that all indicators are calculated correctly. Otherwise, the integrity of the structure during operation may be violated.
How to calculate indicators correctly
When calculating the attic plan and putting it into practice, an important place is occupied by how correctly all indicators were found. First you need to find the value of the attic floor area. Pay attention to what sizes he has the most optimal:
- Floor height - 2 m.
- Optimal width - 3 m.
If you make an attic room with this size or more, you will ensure comfortable living in it. Be sure to determine the deaf area of the floor. The article provides a photo of the attic of a gable roof and a broken line. They have differences, in particular, in the usable area of the floor.
The basic rule when calculating the usable area is that you need to take into account the distance from the ceiling bend to the floor surface. It is recommended to stick to the valueat 0.9m or more. The rest of the attic floor area can be considered deaf, it is simply irrational to use it for living.
To calculate the roof area, you need to add the corresponding values of the individual elements. In other words, if the attic is under a gable roof, then you need to add up the areas of two slopes. If the structure is broken and symmetrical, then you need to add the areas of the ridge and side slopes, and then multiply by 2. The photo of the attic with a gable roof shows what differences there are from the broken structure.
And now let's talk about how to calculate the parameters of the truss system:
- Calculate the angles of inclination of the side and ridge rafters.
- Calculate the amount of material that is needed to make the truss system (ridge and side parts).
- Determine the parameters of the crate.
- Consider how much material you need to spend to make the crate.
- Combine all the data and make a complete list of materials.
And the last step is to calculate the cost of materials. It all depends on the size of the structure and the version. You also need to consider manufacturing costs - if you hire workers, then prepare to give at least another 75% of the cost of the material.
Rafter angles
When drafting an attic with a gable roof, you need to take into account the angle of inclination of the side elements. Of course, it all depends on the particular house andvalue can be anything. For example, when calculating the angle of inclination of the side rafters of a sloping roof, its minimum value of 60 degrees should be taken. When calculating, you should rely on the following methods:
- The simplest and most reliable is the geometric one. When making calculations, it is enough to use the Pythagorean theorem.
- You can use reference books to determine the angle of inclination.
- Method based on geometric constructions. In this case, a plan is built to scale, then all the necessary parameters are calculated.
- You can use construction calculators offered by roofing companies.
If you decide to install a broken roof, then you must adhere to the angle of inclination of the ridge rafters at 30 degrees. This is the most optimal value. When making an attic with a gable roof with your own hands, this value is not taken into account. We will talk about the parameters of the gable design later.
How to calculate roof area
In order to purchase roofing material, insulation, lathing, finishing panels, you need to correctly calculate the roof area. For convenience, you need to break the entire surface into simple components. So, in the case of a gable roof, it is necessary to break it into two identical elements. To calculate the area of one, you need to multiply the length by the width. Multiply the resulting value by 2 and get the total surface area.
But this is for the case when you make a gable roof on a house with an attic. IfIf you decide to make a broken roof, you will have to break the entire surface into 4 sections. To calculate the area of one slope, you need to add the corresponding parameters of the side and ridge parts. The total area value can be obtained by multiplying this result by 2.
Calculating the area of the attic room
The parameters of the attic floor are determined by the area of the room on it. In order to calculate the area, you need to determine the line of the walls. To calculate the area, you need to multiply the length of the room by its width. If the walls of the attic room pass along the lines of the racks, then you need to resort to a different calculation method. Multiply the length by the distance between the opposite posts.
If the room has a complex shape, then you need to divide it into simpler sections (triangles, squares, rectangles) and first calculate their areas. Then all the obtained values must be summed up.
How to calculate the mass of roofing material
Of course, the accuracy of the calculations is quite low, but the approximate mass can still be calculated. This data will be useful to you when calculating the maximum load and choosing the material for the truss system. Yes, 1 sq. m has the following mass:
- Soft types of tiles - from 9 to 15 kg.
- Slate - from 11 to 13 kg.
- Metal tile - from 5 to 6 kg.
- Ceramic tiles - from 50 to 60 kg.
- Galvanized sheet metal - from 3 to 6.5 kg.
How much insulating material is needed
When insulating the attic of a gable roof, you can use both rolled andand board materials. It is not worth using bulk (for example, expanded clay). We will focus on roll materials, as they are the most convenient to use. When making a calculation, you need to take into account an overlap of 10 cm. Standard sizes of roll insulation: length - 10-15 m, width - 1 m.
Be sure to find out what sizes the material actually has before buying. Depending on which manufacturer, sizes may vary. After all, the technical conditions for manufacturing are different for all manufacturers. Knowing the dimensions of the roll, you can calculate its area. To find the number of rolls, you need to divide the roof area by the same amount of insulation material. But you need a margin - do not forget about the overlap.
How to calculate the load on the rafters
It is necessary to take the average value of the load - about 200 kg per linear meter. If you make the rafters with this load in mind, your roof will be able to withstand the effects of wind and snow. When making calculations, it is recommended to use reference data and tables with snow and wind load coefficients. For example, in various regions of our country, the load created by snow (maximum) can be 220 kg or a little more. 220 kg is the average value for all regions of the Russian Federation.
When calculating a specific design, it is necessary to take into account correction factors that depend on the angle of inclination of the roof:
- More than 60 degrees - the coefficient does not need to be taken into account.
- 25-60 degrees - ratio1, 25.
- Less than 25 degrees - factor 1.
Consequently, when calculating the load created by a layer of snow, both the average value (220 kg) and correction factors must be taken into account. So, if the angle of the ridge part is 30 degrees, then you need to multiply 220 by a factor of 1.25. You get 275 kg per square meter.
When calculating the length and width of the roof, you need to use the simplest mathematical formulas. To make calculations easier, divide the entire structure into simple components.
Rafter lengths
There are rafters in the device of a gable roof with an attic. They are located directly on the walls of the house. Be sure to make a removal outside the walls of the order of half a meter. See an example of a gable roof design with an attic.
The attic room is highlighted in the picture. H is the height from the floor surface of the room to the ridge, L is the length of the rafter leg. Removal outside the outer walls - 0.5 m. To find L, you need to use the Pythagorean theorem (you should get a rectangular triangle). But you will need to know the length of two legs - this data is in the project. The article also contains photos of the inner attic. Gable roof projects are the most attractive as they are easier to build. For example, you have a height of 3 m, and the second leg is also 3 m. The formula for calculating is:
L2=H2+A2
L=(H2+A2)1/2
L=(9+9)1/2
L=4, 24 (m).
The calculation of a polygonal structure is somewhat different. This happens due to the fact that the shape of the rafters is somewhat different. The system also contains ridge rafters.
How many rafters do you need?
When calculating the number of rafters, you need to take into account what linear dimensions the house has, as well as what area of \u200b\u200bthe roof. Be sure to install the rafters at the same distance. Standard wood rafters with a section of 50 x 100 mm are mounted at a distance of 70-80 cm. Provided that the leg length is over 6 m. If the leg length of the rafters is 3-6 m, then you need to put them at a distance of 1.2 m.
When calculating broken and gable roofs, you must adhere to the following parameters - the cross section of both side and ridge elements should be from 50 x 100 mm. When making calculations, you need to take the average wood density at a relative humidity of 18%. This is 500 kg per 1 cu. m.
Crate
But not everything is still taken into account, before you make an attic with a gable roof, you need to calculate the amount of material for the crate. Consider the following data:
- For a soft type of roofing material, you can make a sheathing from OSB boards or plywood.
- If semi-rigid materials are used, it is best to mount a compacted or sparse crate.
- If the roofing material is hard (for example, slate), you need to make a sparse crate.
- For semi-rigid large-size material, you need to make a continuous crate.
To find the number of rows, you needuse these guidelines:
- For a roof with a small slope (less than 12 degrees), you need to make a solid type crate.
- When the slope is less than 60 degrees, the crate must be laid in increments of 0, 2-0, 23 m.
- If the slope is more than 60 degrees, then the crate is mounted in increments of 0.6 m.
Usually equip a crate of edged boards with a width of 0.2 m. Lay them at a distance of 0.2-0.3 m from each other.
How many rows of battens do you need?
So, let's say you decide to use an edged board 200 x 20 mm for the manufacture of the crate, and the distance between adjacent rows is 200 mm. Therefore, three rows of crates must be laid on one meter. But if you increase the distance between adjacent rows (for example, make 300 mm)? Only two rows will fit on one meter. If you are calculating a broken system, then you will need to add two more rows - a cornice and a ridge.
The distance between the rows must be maintained the same so that the strength is maximum. After all, it is necessary to take into account the fact that the entire system must withstand both the mass of the roofing material and the effects of snow and winds. And most importantly - with the same distance between the rows of the crate, you will be able to mount the heat-insulating cake with the highest quality.
Number of boards for making crates
Standard lumber is used, both hardwood and softwood can be used for the manufacture of lathing. Standard lumber:
- From softwood - length 4, 5 and 6 m.
- Hardwood– no more than 5 m.
- Softwood for special needs - 9 m long.
Based on this, we can say that for a house of 8 x 10 m on a roof slope 10 m long, you need two boards of 6 m each. Be sure to take into account the protrusion of at least 20 cm.
But after all, all boards are usually sold not in pieces, but in cubic meters. To find the volume, do the following:
- Count the number of boards needed to make the crate.
- Convert all linear dimensions to meters for further calculations.
- Multiply the number of boards by all sizes of one.
For example, you need 10 identical boards measuring 200 x 20 mm and 6 m long. 200 mm is 0.2 m, 20 mm is 0.02 m., 24 (cubic meters).
The total mass of wood from which the crate is made can also be calculated and it will not be difficult. So, at a relative humidity of 18%, a cubic meter has the following mass:
- Common spruce - 450 kg.
- Cedar pine - 440 kg.
- Scotch pine - 510 kg.
- Siberian fir - 380 kg.
- Caucasian fir - 440 kg.
It is recommended to use the average value of the mass of rafters and battens in the calculation - 500 kg per 1 cu. m. Therefore, if you need to spend 10 boards on the manufacture of the crate (from the calculation above), then their mass will be equal to 0.24 x 500=120 kg. This is the total mass of the entire structure of the crate.
A little about design and calculations
During the construction of the attic (projects withgable roof and a photo of the internal space are given in the article) you need to adhere to the general design of the building. Be sure to draw up a detailed plan of the roofing system, build the most detailed drawing showing all dimensions to scale. It is recommended to rely on the standard sizes of building materials that are produced by the industry. For example, you need to take into account that the boards will have a standard length - 4, 5 or 6 m.
When carrying out finishing work, you will also need the data that was obtained at the design stage. After all, the amount of material for wall cladding can be calculated by referring to the data on the area of \u200b\u200bthe roof. All these calculations must be made as accurately as possible so that during the manufacture of a gable roof with an attic there is not a large amount of "extra" building material.
