For low-rise buildings, a rafter roof is perfect. It will decorate the facade of the house, and with a sufficient slope, snow does not accumulate on such a roof, unlike a flat structure.
One of the types of roof rafters - gable. This is enough simple system, which is formed by two slopes. The slope of the roof is the entire inclined plane, with the help of which a drain is provided.
The structure rests on two parallel walls. Such a roof forms two triangular side pediments. A pediment is the end of a building's facade.
Advantages of a gable system
- Ease of Design.
Calculation of the bearing capacity and necessary materials for the installation of such a roof is quite simple, since there are few options for the types and sizes of supporting structures; - Ease of installation.
The gable roof does not have complex structural elements. A small number of standard sizes allows you to quickly install all the elements of the roof; - Ease of use.
The fewer different breaks the roof has, the more reliably it protects the home. In the simplest version, a gable roof has only one break - a ridge. Such a roof is easier to repair in case of defects; - Free space.
For the arrangement of the attic, a gable roof is preferable, since it “eats up” space less. For comparison, consider a 6x6 m house with an attic. At the outer walls, the height from the floor of the room to the roof is 1.5 m, at the ridge - 3 m. For a gable roof under such conditions, the volume of the room will be 81 cubic meters, and for a hip roof with four slopes, 72 cubic meters. For large sizes building volume loss will increase.
Construction types
There are four main types of gable roofs:
- symmetrical.
Reliable, stable, easy to perform, based on an isosceles triangle; - Asymmetrical.
The ridge is not located in the center, the roof slopes have different slopes; - Polyline symmetrical.
Roof slopes are broken. Significantly increases the height of the room; - Polyline asymmetrical.
The attic or attic room is smaller than in the previous case. The roof has a very unusual appearance.
The choice of the type of gable roof depends on the purpose of the room located directly under it and the architectural appearance of the building.
General principles for calculating the truss system
The most important bearing parts truss system The gable roof of the building is the Mauerlat, crossbar and rafters. Mauerlat works in compression, so its cross section can be taken conditionally.
The crossbar and rafter legs experience a bending moment.
The calculation of such structures is carried out in terms of strength and stiffness. For small buildings, you can choose their cross section approximately, but for serious buildings, for safety and material saving purposes, the calculation of the truss system should be performed by a professional.
Roof self-weight load
To perform the calculation, you need to know the load per 1 sq.m. roofs.
To do this, you need to add the masses of 1 sq.m. all roofing materials:
- filing(if it is, it is most often performed from drywall);
- rafter legs. To calculate the weight of the rafters per square meter of the roof, you need to find the mass of the linear meter rafter leg and divide this number by the pitch of the rafters in meters. For the calculation, you can take the approximate cross section of the rafter, the area of \u200b\u200bthis section must be multiplied by the density of the wood;
- heater (if any). The density of the insulation must be indicated by the manufacturer, it must be multiplied by the thickness;
- crate. To ensure a margin, a continuous crate can be taken into account. For example, 1 sq.m. lathing from a board 32 mm thick will weigh approximately 25 kilograms;
- roofing material. Weight 1 sq.m. coatings are usually specified by the manufacturer.
Snow load
The snow load for each area is different and is equal to the weight of the snow cover on a horizontal plane.
On the territory of Russia, it can take values from 80 to 560 kilograms per square meter. On the Internet, you can easily find a snow load distribution map and select the right number based on the construction area.
Roof pitch
The angle of inclination of the roof is quite easy to calculate, knowing the geometry and having an engineering calculator or a standard calculator on a personal computer at hand.
If we divide the height of the roof rise by the distance from the ridge to the cornice in the plan, we get the slope of the roof in fractions or the tangent of the angle of inclination. In order to calculate the angle, it is enough just to find the arc tangent.
If using an engineering calculator is difficult, the arc tangent can be found using an online calculator.
Rafter step calculation
Rafter step mansard roof should be chosen for reasons of ease of installation of insulation. Mats usually have a width of 60 centimeters, so the pitch of the rafters should be chosen so that the distance between them in cleanliness is 58 or 118 centimeters. Two centimeters will allow you to install the insulation boards very tightly, which will allow it to stick between the rafters and improve thermal insulation.
Rafter leg length
Leg length is easy to calculate using the formula:
L/cosα,
where L is the distance from the roof ridge to inner surface outer wall in plan, and cosα is the cosine of the angle of inclination of the roof. With rigid fastening, you need to add the size of the notch.
Section of the rafter leg
The cross section of the rafter leg must be selected as a multiple of the size of the boards and timber.
An example of a simple calculation of the section of the rafter leg:
- find the load on 1 running meter rafters.
q =(1.1*weight of 1 sq.m. of roof*cosα + 1.4*normative snow load*cosα2)* rafter spacing; - find W.
W= q * 1.25 * flight of rafters / 130; - solve the equation:
W= b*h2/6.
In this equation, b is the width of the section of the rafter leg, and h is the height.
To solve, you need to ask for the width and find the height by solving a simple quadratic equation. The width can be set to 5 cm, 7.5 cm, 10 cm, 15 cm. For small spans, a width of 15 cm is impractical.
To calculate the truss systems, there are all kinds of tables, programs, online calculator s.
The main elements of the roof
The main elements of a gable roof, like any other roof truss, are:
Rafter roof with attic
To fully use the space under the roof, you can design an attic.
Attic floor- This is the floor in the attic space. The facade of the attic is completely or partially formed by the roof surfaces. According to regulatory documents, in order for a room to be considered an attic, the line of intersection of the roof plane and the outer wall should not be higher than 1.5 m from the floor level. If this requirement is not met, the space will be considered a normal floor.
Roof attic floor differs from the attic roof by the presence of a heater in its design. Mostly for insulation. mansard roof mineral wool boards are used.
Lighting of the attic space can be carried out in three ways:
- window openings in the gables;
- dormers;
- roof windows.
dormer window - This window construction, which has a frame mounted simultaneously with the truss system. This frame is made of wood. The dormer has its own small roof, which can be gable or cylindrical. The double-glazed window is installed vertically.
roof window- This is a window specially designed for use on a rafter roof. It is installed in the plane of the slope in an inclined position. The roof window must withstand the calculated snow load. It is better not to use this type of windows in roofs with a slight slope.
The choice of roofing material
After the appearance of the roof is determined, you can proceed to the choice of material. There are several types modern coatings. In the list below, material options are listed in descending order of average market value.
- Ceramic tiles.
Ceramics, as a roofing material, has long history. The ceramic roof is reliable and durable. The disadvantages of this material are the price and the large mass. Under the roof of ceramic tiles, you will have to arrange a reinforced truss system and crate; - Cement-sand tiles.
It has almost all the characteristics of ceramic, but costs a little less; - flexible shingles
.
It has good soundproofing characteristics. Thanks to the rough surface, the tiles are able to prevent snow from moving off the roof. Requires a continuous crate, usually a layer of moisture-resistant plywood is used. Cannot be used on roofs with large slopes; - Metal tile.
Compared to previous coatings, it is lighter in weight. Easy to mount. The disadvantage of a metal roof is that it can be too noisy when it rains. - seam roof.
The most attractive option in terms of cost. It requires special qualifications during installation, since it will be difficult for a non-professional to make high-quality connections. Installation is more laborious than that of metal and shingles. The same "noisy" as metal tiles.
The material of the roof depends entirely on the desires and capabilities of the customer. The exception is roofs with too much or too little slope, since all materials have limits on the slope of the slope.
Types of truss systems
Structural roof truss systems can be of three types:
- Rafters.
The rafters rest on two sides. From below - on the Mauerlat, from above - on the crossbar. Racks and struts can be used as intermediate supports. Most often used in buildings with a small distance between the ends or, if possible, put racks or a wall in the middle of the attic.
With large spans of rafters (large distances between the longitudinal walls), racks, struts or puffs can be additionally used.
Laminated rafters are easy to calculate.
Usually the most powerful element such a system is a crossbar, which bears half the load of the entire roof structure. - Hanging rafters.
In the absence of the possibility of using a crossbar as an upper support, it is reasonable to use this truss system.
Hanging rafters rest only on the Mauerlat, and at the top point they are interconnected with the help of an overlay.
This truss system works like a truss under load. Maximum pressure falls on the outer walls. There is a horizontal force - thrust, which can lead to displacement of the walls. In the design of hanging rafters, the expansion force is perceived by a puff, which tightens the rafter legs and prevents them from moving apart.
Hanging rafters are classified depending on the location of the puff:
1) Triangular three-hinged arch.
The puff and rafters form a triangle. The puff is located at the level of the overlap;
2) Triangular three-hinged arch with suspension.
With a large span of rafters, the tightening may not pass according to the deflection requirements. To prevent it from sagging, the puff is suspended from the ridge. But with such a system, as well as with a system of layered rafters, a row of racks is formed in the middle of the attic;
3) Triangular three-hinged arch with a raised puff.
The puff is most often located at the level of the ceiling attic space. Such a scheme is less beneficial from the point of view of the design. The higher the puff is located, the greater the thrust it perceives.
Hanging rafters must be considered as a triangular truss, which complicates the calculation. - Combined rafters.
The combined system includes spacer layered rafters. They need both bolt installation and tightening. Unlike the previous options, in which the rafters are hinged to the Mauerlat, here the rafter leg is rigidly attached, so there is a thrust in the system. For such a system, the Mauerlat must be securely attached to the wall, and the wall itself must be strong and thick. Great option camp execution along the perimeter of the reinforced concrete belt.
Installation of the truss system
Installation takes place in the following order:
- mauerlat laying;
- installation of a crossbar (if any);
- layout of rafters;
- insulation (if any);
- crate;
- roofing material.
Attaching the rafter leg to the Mauerlat can be rigid and articulated.
Hinged fastening
It makes it possible to compensate for the expansion of wood under the influence of humidity and temperature changes.
Fastening can be done in several ways:
- using special fasteners, a metal "sled";
- using a mounting plate;
- washed down on the rafter leg. The junction of the rafter leg and the Mauerlat is fixed with nails.
Rigid fastening
The rafter is attached to the Mauerlat with a notch and securely fixed with nails hammered at an angle with respect to each other. One nail is driven vertically into the surface of the Mauerlat. Such a connection excludes displacement in any plane.
The gable truss system has undeniable advantages. You can design and install it yourself, you just need to take this issue responsibly and think through everything to the smallest detail.
The website of our company provides the most wide choose roofing materials from the best manufacturers for full or partial replacement roofing: natural ceramic tiles, soft bituminous tiles, metal seam roofs, roofs from metal profile sheets, metal tiles with various types protective and decorative coatings.
Prices from the manufacturer
Our company FS-Group is the official dealer of roofing materials manufacturers presented on our website, which guarantees the best prices for you.
Roofing material and installation warranty
When concluding an agreement with us for the installation of a turnkey roof, you simultaneously receive warranty for both roofing materials and installation work in one contract.
Calculation and selection of materials
At present, the range of roofing materials is quite wide, because of this, it is difficult to make right choice. Call our qualified managers and they will help you choose exactly the material for your roof that you need.
field manager
If you need to accurately determine the cost of replacing the roofing, order the service of a manager to visit the facility. He will not only give advice on the choice of roofing material, but also calculate the required amount of it, as well as the required amount of additional materials, and show samples of materials.
All types of payments and credit
We accept all types of payments: cash, bank transfer, payment by bank card in our office and online. All operations for payment for goods are carried out on the principles of confidentiality and security of payment. It is possible to pay for goods on credit, for details, contact our managers.
Delivery to the object
When concluding a contract for the purchase of goods, a delivery service from our warehouse to the object is possible. In this case, you must contact our managers, as the cost of delivery depends on the distance to the object.
Experience over 12 years
We have been in the market of installation services for more than 12 years. We successfully apply the accumulated experience at the facilities of our clients. The experience of our teams allows us to take on the most complex projects and implement them with maximum quality.
All parameters must be specified in millimeters
B- The length of the roof.
Y- Height.
C- Overhang distance.
X- Roof width.
Y2- Additional height.
X2- Additional width.
This program will help you perform an accurate calculation of building materials for the construction of a roof: the number of rafters and sheathing boards, roofing material (roofing material, glassine), the amount sheet material(metal tile, slate, nulin or ondulin).
Our online calculator will calculate other useful roof sizes.
The presented program performs the calculation in two versions: type 1 - simple gable roofs, type 2 - gable roofs with 2 side gables.
If the projected roof has only one side pediment, then in this case we perform the calculation by type - 1, and then by type - 2. Based on the results of the calculations, you can determine the required amount of materials: roofing, sheet, rafters and sheathing board.
Otherwise, you will make an error in the calculation, since the program takes into account the cutouts for the side fronts when calculating the parameters of the main roof.
Based on the results of the calculation, you get the volume and size of the material for one roof slope, and the entire volume and size will be indicated in brackets.
When calculating the volume and useful dimensions of an additional roof, you get two parameters in parentheses: the volume and size of one or two additional roofs.
Important! It is worth considering that the program performs a calculation over the entire area of the roof, when determining the number of sheets of roofing material.
For example, a row takes 7.7 sheets, and only 2.8 rows. Based on the results of the calculation, you will receive 3 real building rows.
In the event that you want to get the exact number of sheets for the future roofing, you need to reduce their height until you get an integer number of rows.
Do not forget to set the exact length of the overlap.
Important! In type 2 mode, while calculating the amount of material for rafters main roof, the program does not take into account the cutouts for the side gables. This calculation of the gable roof truss system is associated with the design of the program itself.
Also, the remaining building material for the rafters, you can use to build or repair a house, otherwise you can make corrections to the calculations.
The exact calculation of the approximate cost of the roof depends on the correct basic measurements.
Important! Do not forget to purchase building materials with a margin of 5-10% for waste.
Do-it-yourself gable roof
First of all, we need a diagram (drawing or design) of a gable roof, according to which we will perform all calculations (listed above).
The procedure for erecting a roof is quite simple, but the sequence of certain steps must be followed.
Before you install beams or transfers for future flooring, you need to determine whether an attic or just an attic space will be equipped. As a rule, for a simple attic, it is enough to choose a board 150x150 mm. In the event that you plan to build an attic, then it is best to choose a bar with the same size. To increase the strength of the frame, you should mount the bars or boards exclusively on the walls.
The process of fixing the beams is carried out taking into account the release from the outer edge by about 400 mm in order to prevent precipitation or wind from entering under the roof.
We will use a board edged under 50X150 mm when arranging the attic frame, and fixing is carried out with roofing nails. To give gable roof stability, it is necessary to perform all measurements correctly, trying to eliminate the error.
Now we turn to the assembly of the truss structure, starting the installation from the gables, using the method already described above. At the same time, we saw off the lower parts of the boards, which will give our rafter structure additional stability.
When the structure is fully erected for a gable roof, we begin to cover with roofing materials.
Advantages of a gable roof:
- This design is quite simple to build, which allows you to perform all the work yourself without the expensive help of specialists;
- The building materials used are affordable;
- The large angle of inclination of the roof perfectly removes water during precipitation;
- Absence complex structures and kinks, greatly facilitate the construction and cladding of the roof.
When carrying out any construction works, and roofing including, an accurate calculation of the material is necessary, both the main and the auxiliary. Thanks to a thoughtful approach to determining the right amount finish coat roofing, as well as accessories and Supplies(insulation, waterproofing, crate, fasteners) you provide yourself with several advantages at once:
- You buy everything at once in one place, guaranteeing yourself a complete match of the material in color. The need to purchase material elsewhere, from a different batch, can lead to the fact that the difference in shades will be clearly visible on the finished roof. Why do you need it?
- Accurate calculation of the roof will help to avoid the need to subsequently buy additional material, and this requires time, effort, additional costs (there is a difference, bring everything you need with one car or hire special vehicles several times).
- Calculation of the roof from specialists is a guarantee of the absence a large number unnecessary surplus. Then you also need to do something with them (sell, take them out of the site), and this is also a waste of time and money.
Before starting the construction of the roof, it is necessary to calculate the material. Especially for this, we have an online calculator on our website. Its main purpose is to help the buyer estimate the approximate cost of roofing material. Knowing the amount of metal tiles, corrugated board, flexible tiles that you will need to buy to cover the roof, you can calculate the approximate cost of the roof (excluding discounts and possible bonuses).
Also, the roof calculator will allow you to calculate the approximate cost of the roofing work itself, since knowing the amount of material you can calculate this value. Knowing these figures, you will be able to fully prepare for such an important and responsible event as the purchase of material and the conclusion of a contract for roofing work.
Calculation results
Above the roof layout there are product profile switches, they will allow you to select the required profile, taking into account its working width and forbidden lengths. To view the layout of sheets on a ramp, select the ramp by clicking on it. Use the arrows to change the length of the sheets according to your need for the selected slope.Calculation results
Below are the parameters of your roof and the amount of material needed, taking into account the forbidden lengths and overlaps of the sheets. Then you can add the product to the cart and, if necessary, refuse any items in the cart.How does the online roof calculator work?
First of all, the determining factor in the calculation of the roof is its shape. When filling in the fields of the online calculator, you can select the type you need, this step will be the very first. You will be able to calculate a single-pitched, double-pitched, four-pitched hip, mansard roof, etc.
Also included in the online calculation of the cost of the roof are other parameters that affect the amount of material - the need for insulation, additional elements (overhangs, gutters, etc.). The greatest attention, of course, should be paid to the size of the roof. In order to obtain the most accurate calculation possible, refer to the drawing when specifying the dimensions.
As a result, the online calculator for the roof of the house will give you all the necessary numbers, taking into account the choice of the type of metal tile profile and the cost of all the necessary materials at Roofing No. 1. The program will calculate the total area of the roof, the cost of the finish coating, additional elements, fasteners, as well as the cost additional elements, if you indicate this when filling out the form (insulation, waterproofing, drainage system, spotlights). Also, the roofing cost calculator will calculate the amount for turnkey installation work. The final amount will reflect all your expenses, both for the purchase of material and for the installation process.
How to buy materials after calculating the roof?
You can order and buy everything you need for roof installation right here without leaving the calculator page. The order will be automatically generated in the basket, you can make all the changes you need to it, refuse some of the goods or services and calculate the final cost. You can pay for the purchase directly through the site using a bank card, cashless transfer. Cash payment is made at the office of the company.
It is very convenient, it allows you to save your time and money, and also to purchase everything you need for the roof in one place, without tiring trips in search of the necessary materials.
This online calculator allows you to get a fairly accurate preliminary calculation, which is especially suitable for those who plan to build a roof of a simple form. If there is a project for a complex, multi-pitched roof with skylights, for the calculation of the cost, it is best to contact the specialists of the Roofing No. 1 company.
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During the construction of a new house, the question often arises about the amount of lumber for the roof. And this question is really important. After all various materials for the roof they are not cheap at all and if you buy too much, then the money will simply fly out into the pipe. At the same time, if there is not enough material, this will cause construction downtime and, possibly, additional costs for the delivery of a new batch. That is why the calculation of materials for the roof is a burning issue, on which the final stage of building a house depends.
As you know, when designing a house, a preliminary calculation of the forest on the roof is made. On this stage work is determined by the strength of the structure, its resistance to climatic conditions. If structural strength calculations have not been carried out, then the roof may eventually turn out to be unstable to the action of wind and snow, which can lead to inevitable consequences.
Well, let's take a closer look at the calculation of the material on the roof of the house. In preliminary calculations, the thickness and type of insulation, the material for creating the crate, must be taken into account.
Types of roofs, materials
Roofs can be made in classical form, and in a completely fantastic one, but basically it is:
- classic single or multi-slope;
- broken line;
- hip, semi-hip, tent;
- oblique;
- domed;
- folded;
- cruciform;
- flat;
- spherical;
- spire-shaped.
Various loads act on the rafters - their own weight and the weight of the roofing material, wind loads and the impact of precipitation. For the arrangement of rafters, battens and Mauerlat, high-quality and well-dried lumber from conifers tree. It is this wood that is most resistant to moisture and decay.
A roof is laid on the rafters, the calculation of materials and the method of fastening of which depends on the type chosen. It can be nails, dowels or special glue. Can be used as a roof different materials- aluminum, copper, ondulin, ceramic or metal tiles, bitumen, polymers, etc. Styrofoam and glass wool are most often used as insulation.
How to calculate the materials for the roof
After the rafters are installed on the waterproofing, you can start laying the counter-lattice. It is designed to drain condensate and circulate air. can be either solid or certain step. It all depends on the chosen material of the roof and the angle of its inclination. The step should be considered carefully so as to avoid deformation or collapse of the roof.
Calculation of lumber on the roof
The calculation of the material for the roof of the house is affected by the step or distance between the bars. In order to determine it, you must first (primary and secondary). In this case, the main point is to provide some margin of safety to maintain the integrity of the roof in extreme conditions (heavy snowfall, hurricane).
The main load is the weight of the roof elements and the weight of the roofing cake. The secondary load is the force of the wind, rain, snow, etc.
The calculation of the roof is carried out according to the following scheme:
The calculation of roofing material for the roof and the main loads is best done using a calculator or Excel program. This will help avoid mistakes. Also on the Internet you can find various calculator programs that help calculate the various characteristics of the roof.
Below we give some examples of calculations of various roof parameters for several types of materials. Suppose that we have already calculated the Mauerlat parameters, also we, the slope and height of the roof. Using the normative table, it can be determined that the total load on the roof structure will be 2400 kg / m, while permissible load 1 linear meter of wood is 100 kg. Thus, it can be done by calculating the required footage of the rafters. To do this, simply divide the first indicator by the second: 2400/100 = 24 m.
If the length of one rafter is 3 meters, then their total number will be: 24/3 = 8 pcs. Naturally, the number of pairs will then be 8/2 = 4. The maximum step is calculated based on the length of the roof (in our case, it is 4.5 m) and the number of pairs: 4.5 / (4-1) = 1.5 m. In this formula we subtracted the very first from the number of pairs, that is, in total there are three gaps between the rafters.
In order to provide the roof with greater stability and strength, the rafters are installed at a smaller pitch. To do this, you can add a few more pairs to the estimated number of rafters so that the distance between them does not exceed 100 cm.
Calculation of materials for construction, detailed video:
Based on this, to fill one row, it is necessary to use 6 sheets of metal tiles. Next, the number of rows of material from the ridge to the cornice is calculated.
- the distance from the eaves to the ridge is measured;
- the overhangs of the eaves are calculated;
- the value of the vertical overlap is determined (no more than 15 cm).
For example, the width of the slope is 4 m, and the overhangs are 30 cm. Thus, the total distance from the lower edge of the roof to the upper one is 4.3 m. The standard length of a metal tile sheet is 1 m. This means that the effective indicator of this parameter will be 85 cm ( subtract the amount of overlap). We divide the indicator of the total length of the roof by the effective length of one sheet and we get that 4.3 / 0.85 = 5.05 sheets must be used for laying. Since rounding down we will have a shortage of material, in reality we will have to use 6 rows.
We multiply the indicator of the number of sheets vertically and horizontally and get the total amount of material per slope: 6 * 6 \u003d 36 sheets.
