Techniques for lengthening rafters from boards 50x150. Do-it-yourself gable roof

What is a rafter?
rafters- these are the main boards of our roof, on which the roofing rests. This is how they usually look in a frame house:

What do you need to know about?

The angle of the rafters.

Usually it is chosen according to your taste and color, for example, someone likes a sharp roof, someone sloping.
Sloping roof example:

An example of a sharp roof:

I decided to make myself something in between and chose angle of inclination of the rafters 26 degrees. As in this photo of a frame garage:

Section of rafters.

The rafter board is also an important point. Usually for rafters used board 150×50 or 200×50. The required section for the rafters can be calculated. If a very clear video on how to do it:

An example of calculating using the formulas from the video above for my house:
Snow load= 240kg/m2. Because the roof angle is 26 degrees, then the MJ coefficient remains = 1. 240x1=240.
Wind load 32kg/m2. I multiply it by 0.65, since there are many obstacles near the house 32 * 0.65 = 25.6 kg / m2.
The weight of bituminous tiles is 10 kg/m2.
OSB-3 weight 8 kg/m2
Inch weight 20kg/m2

Total. Total load per 1m2 = 240+25.6+10+8+20= 305 kg
My roof area is 110m2. Total load on the entire roof is 110 × 305 = 33.5 tons.
We are looking for a load on the p.m. rafter leg \u003d 305 * 0.8 (rafter pitch) \u003d 244 kg/m.
We consider the cross section of the rafters.
Rafter section >= 8.6 * 3 (area in the rafter before the braces) * Square root of (305/ 0.05 * 130) >= 176.73 mm.
This means that the cross section of my rafter with a thickness of 50 mm should be more than 176 mm, which is why I chose the board 50×200.

Rafter step.

Now that you have decided on the cross section of the rafters and their angle of inclination, you need a specialist who will design the correct truss system and choose the step with which the logs will go, as well as how they will be attached to other elements of the frame roof. Standard rafter pitch 600 mm, but there are also 400 mm, and 800 mm, and 1 meter. Rafters are a complex element, but their calculation is often templated and can be done even according to regulatory documents. Ready-made solutions for typical floor spans are present in large numbers on forumhouse.ru.

Rafter attachment points in pictures.

Now you know what rafters are, how to calculate the cross section of rafters, how to choose boards for rafters, and much more. If you have any questions about the rafters or any other questions about the construction of a frame house, you can order a frame house construction.
I also did not begin to mention truss systems and their types in this article. This is a topic for a separate detailed analysis.

Roof installation is a complex multi-stage process. In order to independently assemble and install the truss system, it is necessary to carefully study the methods of connecting the elements, calculate the length of the rafters and the slope angle, and select the appropriate materials. If you do not have the necessary experience, you should not take on complex designs. The best option for a small residential building is a do-it-yourself gable roof.

A standard roof of this type consists of the following elements:

Mauerlat is a beam laid on top of the walls along the perimeter of the building. It is fixed with threaded steel rods immured into the wall or anchor bolts. The beam must be made of coniferous wood and have a square section of 100x100 mm or 150x150 mm. Mauerlat takes on the load from the rafters and transfers it to the outer walls.

rafter legs- these are long boards with a section of 50x150 mm or 100x150 mm. They are attached to each other at an angle and give the roof a triangular shape. The design of their two rafter legs is called a truss. The number of farms depends on the length of the house and the type of roofing. The minimum distance between them is 60 cm, the maximum is 120 cm. When calculating the pitch of the rafter legs, one should take into account not only the weight of the coating, but also the wind load, as well as the amount of snow in the winter.

It is located at the highest point of the roof and most often represents a longitudinal beam connecting both slopes. From below, the timber is supported by vertical racks, and the ends of the rafters are attached to the sides. Sometimes the ridge consists of two boards, which are nailed to the top of the rafters on both sides and connected at a certain angle.

Racks - vertical bars with a section of 100x100 mm, located inside each farm and serving to transfer the load from the ridge run to the load-bearing walls inside the house.

The struts are made from timber scraps and set at an angle between the uprights and the rafters. The side faces of the truss are strengthened with struts, the bearing capacity of the structure is increased.

Puff - a beam connecting the lower parts of the rafters, the base of the truss triangle. Together with struts, such a beam serves to strengthen the truss, increases its resistance to loads.

Lying is a long bar with a section of 100x100 mm, laid along the central load-bearing wall, on which vertical racks rest. Lying is used when installing layered rafters, when the run between the outer walls is more than 10 m.

The crate is a board or timber stuffed on the rafters. The crate is solid and with gaps, depending on the type of roof. It is always attached perpendicular to the direction of the rafters, most often horizontally.

If there is no more than 10 m between the outer walls and there is no load-bearing wall in the middle, arrange hanging rafter system. With such a system, the upper ends of adjacent rafters are sawn at an angle and connected to each other with nails, excluding the installation of racks and ridge timber. The lower ends of the rafter legs rest on the outer walls. Due to the lack of racks, the attic space can be used to equip the attic. Very often, floor beams perform the function of puffs. To strengthen the structure, it is recommended to install the upper puff at a distance of 50 cm from the ridge.

In the presence of a central supporting wall, the arrangement is more justified layered truss system. A bed is laid on the wall, support posts are attached to it, and a ridge beam is nailed to the posts. This installation method is quite economical and easier to perform. If the ceilings in the interior are designed at different levels, the racks are replaced with a brick wall dividing the attic into two halves.

The installation process of the roof includes several stages: attaching the Mauerlat to the walls, assembling the truss trusses, installing the rafters on the floors, installing the ridge, and attaching the batten. All wooden elements before assembly are carefully treated with any antiseptic composition and dried in the air.

For work you will need:

timber 100x10 mm and 150x150 mm;
boards 50x150 mm;
boards 30 mm thick for lathing;
ruberoid;
metal studs;
jigsaw and hacksaw;
hammer;
nails and screws;
square and building level.

in wooden houses Mauerlat functions are performed by logs of the last row, which greatly simplifies the workflow. To install the rafters, it is enough to cut grooves of the appropriate size on the inside of the logs.

in brick houses or buildings from blocks, the installation of the Mauerlat is as follows:

Mauerlat bars should form a regular rectangle and be in the same horizontal plane. This will facilitate further installation of the roof and provide the structure with the necessary stability. In conclusion, markings are made on the bars for the rafters and grooves are cut along the thickness of the bar.

When choosing a hanging truss system, it is necessary to assemble the trusses on the ground, and then install them above the floors. First you need to draw up a drawing and calculate the length of the rafter legs and the angle of their connection. Typically, the roof slope is 35-40 degrees, but in open, heavily ventilated areas, it is reduced to 15-20 degrees. To find out at what angle to connect the rafters, you should multiply the angle of the roof by 2.

Knowing the length of the run between the outer walls and the angle of connection of the rafters, you can calculate the length of the rafter legs. Most often, it is 4-6 m, taking into account the cornice overhang 50-60 cm wide.

The upper ends of the rafters can be fastened in several ways: overlap, butt and "in the paw", that is, with cut grooves. For fixing use metal pads or bolts. Next, the lower and upper puffs are mounted, and then the finished trusses are lifted up and installed above the ceilings.

The extreme trusses are attached first: with the help of a plumb line, the rafters are set vertically, the length of the overhang is adjusted and attached to the Mauerlat with bolts or steel plates. So that during the installation process the farm does not move, it is strengthened with temporary jibs from a bar. After installing the extreme rafters, the rest are exposed, keeping the same distance between them. When all the trusses are fixed, they take a board with a section of 50x150 mm, the length of which is 20-30 cm longer than the length of the eaves, and nail it along the upper edge of the slope. Do the same on the other side of the roof.

The first option: a rectangular groove is cut out on the rafter leg at the point of contact with the Mauerlat by 1/3 of the beam width. Stepping back from the top of the box 15 cm, a steel crutch is driven into the wall. The rafter is leveled, the grooves are aligned, then a wire clamp is thrown on top and the beam is pulled close to the wall. The ends of the wire are securely fixed on the crutch. The lower edges of the rafters are carefully cut with a circular saw, leaving an overhang of 50 cm.

The second option: the upper rows of walls are laid out with a stepped brick cornice, and the Mauerlat is placed flush with the inner surface of the wall and a groove is cut in it for the rafter. The edge of the rafter leg is cut at the level of the upper corner of the eaves. This method is simpler than the others, but the overhang is too narrow.

The third option: ceiling beams are extended beyond the edge of the outer wall by 40-50 cm, and roof trusses are installed on the beams. The ends of the rafter legs are cut at an angle and rest against the beams, fixing with metal plates and bolts. This method allows you to slightly increase the width of the attic.

The device of layered rafters

1 shows the cutting of the struts of the rafters into a bed laid on intermediate supports, and in Fig. 2 - supporting the rafter leg on the Mauerlat

The procedure for installing a layered truss system:

When the main elements are fixed, the surface of the rafters is treated with flame retardants. Now you can start making the crate.

A beam of 50x50 mm is suitable for the crate, as well as boards with a thickness of 3-4 cm and a width of 12 cm or more. Waterproofing material is usually laid under the crate to protect the truss system from getting wet. The waterproofing film is laid in horizontal stripes from the eaves to the roof ridge. The material spreads with an overlap of 10-15 cm, after which the joints are fastened with adhesive tape. The bottom edges of the film must completely cover the ends of the rafters.

It is necessary to leave a ventilation gap between the boards and the film, so first wooden slats 3-4 cm thick are stuffed onto the film, placing them along the rafters.

The next stage is the sheathing of the truss system with boards; they are stuffed perpendicular to the rails, starting from the roof eaves. The step of the lathing is affected not only by the type of roofing, but also by the angle of inclination of the slopes: the larger the angle, the greater the distance between the boards.

After the installation of the battens is completed, they begin to sheath the gables and overhangs. You can close the gables with boards, plastic panels, clapboard, waterproof plywood or corrugated board - it all depends on financial capabilities and personal preferences. The sheathing is attached to the side of the rafters, nails or self-tapping screws are used as fasteners. Overhangs are also hemmed with various materials - from wood to siding.

Video - Do-it-yourself gable roof

Before installing the truss system, the question arises with what step to put the floor beams. Correctly calculating the distance between the rafters means preventing later deformation or even destruction of the roof frame. After reading the article to the end, readers will find out what the distance between the rafters should be for various types of roofs and how to correctly calculate.

Even at the stage of designing a house made of wood, you need to make all load calculations. This also applies to the truss system. This is especially important in wooden housing construction, since the upper link is often used instead of the Mauerlat. Correcting errors in such a design is subsequently difficult. For the correct calculation of the distance between the beams, there is a technique.

The span of the roof frame for the construction of a house from a bar standardly exceeds 1 m, and the smallest allowable value is 60 cm, such indicators are indicated in GOSTs (see figure). Correctly calculate the length of the rafters, their step can be the following option:

Using a tape measure, the length of the roof slope is measured, the result is divided by the step size of the roof frame. For example, if the distance between the rafters is 1 m, then you need to divide by 1, if 70 cm, then by 0.7. The resulting figure is summed from 1 and rounded up to the nearest higher number. So you can determine the number of beams for one roof slope.

By the result you need to divide the length of the future slope. The result is the distance between each rafter.

For example, consider a roof whose slope is 25.5 m and a step of 0.6 m. You need to calculate the following indicators: 25.5: 0.6 \u003d 42.5, to 42.5 + 1 \u003d 43.5. We round this figure to the nearest larger integer, we get 44. This is the number of rafters per 1 slope of the future roof.

Now we calculate the span between the rafters: 25.5:44 \u003d 0.58 m. It turns out that you need to put the legs of the frame after 58 cm. So you can easily calculate the step of any roof frame, shed or complex, without taking into account the roof. But professionals recommend their calculations for a certain type of roof.

Rafter leg step depending on the material

Since each forging material has its own characteristics and features. Among the most common are:

Decking. It has a different thickness and shape of a tropezoidal bend. It costs from 120 rubles.
Ceramic tiles. Expensive material from 670 rubles. Has 12 color options.
Metal tile. This is a cheaper material, unlike ceramic, and costs from 320 rubles.
Ondulin. Soft roofing insulates the house from rain, hail, etc. It costs from 340 rubles.
Slate. The most economical option from 90 rubles.

The step size for the most common types of coverage will be discussed below.

The step of the rafter beams under the corrugated board

Envy the distance between the roof beams on the size of the sheet that the corrugated board has. The step of the roof frame beams under the corrugated board is taken as a standard not less than 60 cm and not more than 90 cm.

If this distance is greater, then boards with a large section are attached between the rafters. The cross section of the rafter legs for corrugated board is selected 50x100 or 150 mm.

The most important thing to consider when planning to fix corrugated board is the crate. They make it from a board with a section of 30x100mm, you need to mount it with a span of 50 cm or more. It depends on the brand and thickness that the corrugated board and the slope of the roof have.

So a roof of 15º grade C 10 corrugated board is mounted on a solid crate, C 21 corrugated board is mounted on a crate with a span of 30 cm. The largest C 44 corrugated board is mounted on a crate in increments of 50 cm, up to 1 m. passage of a chimney, ventilation hood, etc.

Step of rafter beams under ceramic tiles

The specificity of the installation of a truss system for laying ceramic tiles is related to the weight of this roof. Ceramic tiles are made from clay, and this roof has a weight greater than that of a metal tile by 9-10 times. The calculation of the load on the roof system for ceramic tiles is 40-60 kg / m 2.

Beams are made for the roof truss system under ceramic tiles only from dried material. The cross section is suitable for 50x150 or 60x180 mm. The standard distance between the rafter legs when roofing tiles is 80-120 cm. The span depends on what kind of slope the roof has. At an angle of 15º, the span between the rafters is 80 cm, at 750 after 1 m 30 cm.

When calculating the step, you need to take into account the length of the beam. Taking the maximum length, the distance between the rafters is minimal. And, on the contrary, with a minimum length of rafters, the step is maximum.

When laying ceramic tiles, it is important to consider that you will need to move along the roof. The maximum safe step of the rafter legs for such a movement is 80 cm.

When laying ceramic tiles, it is important to calculate the span of the crate. This distance is directly related to the size of the roofing material. A standard tile sheet is 40 cm long. Laying occurs with an overlap of 50 to 90 mm. When calculating the step of the crate, the size of the overlap is subtracted from the length of the tiles. The result is a step of 305-345 mm.

For a shed roof for the construction of a house from a profiled beam, it is not difficult to make a calculation. If the roof is of a complex multi-pitched shape, then each distance between the rafters is calculated separately for the step of the crate. By fixing the cord on the opposite side of the roof slope, you can easily mark the rows.

Features of the roof frame under the metal tile

Metal tiles are used more often than ceramic or corrugated board. Externally, the roof resembles ceramic tiles, but unlike it, it is easier to install and lighter.

The metal tile weighs from 35 kg / m 2 of the roof. This makes it possible to lighten the design of the rafters and use beams of a smaller section. In this case, the step between the rafter legs of the roof frame increases and is equal to 60 to 90 cm. A beam is used with a section of 50x150 mm.

To create a ventilated space in the beams under the roof, holes are drilled with a diameter of 12-13 mm.

The design of the roof frame for metal tiles is not much different from corrugated board or ceramic tiles. But there is a small peculiarity: the support from above is attached to the ridge run from above, and not from the side, as in other cases. So a ventilated gap will appear under the metal tiles, which will eliminate the accumulation of condensate.

Features of rafter legs for ondulin

Ondulin is a soft roof used for the construction of a house made of glued laminated timber or other material. Ondulin is produced in the form of sheets, it looks like painted slate, but light. This material is great for wooden houses, both low-rise and large.

Rafter beams under ondulin are placed with a distance of at least 60 cm, maximum 90 cm. For the rafter system, a beam of coniferous wood with a section of 50x150 or 50x200 mm is used. A smaller section will not provide sufficient strength to the rafters.

The crate on the rafters is placed from a material with a section of 40x50 mm in increments of 60 cm. This is quite enough for attaching sheets of ondulin with an overlap of 30 cm. Ondulin is fastened with special nails that are sold in the kit.

Features of the truss system for slate

Slate is rarely used to cover the roofs of modern houses. But in summer cottage construction and households. buildings, this material is indispensable. It is low cost and easy to install.

Rafter under slate

Rafter legs for slate are used with a section of 50x100 or 50x150 mm. The fastening step between the rafters is not less than 60 cm and not more than 80 cm.

The crate for slate is made of bars 50x50 mm or a wide board 30x100 mm. The crate is laid from the steps, depending on the slope of the roof. For a steep shed roof, it is 45 cm. The consumption is 4 bars per 1 sheet of slate. For a flat shed or gable roof 63-65 cm, so the consumption is reduced to 4 bars per sheet.

The step of the rafter system under the slate roof structure differs. For the host buildings are often mounted shed.

A feature of the size between the rafters of a shed and gable roof

Whether a safety margin is needed during installation depends on what shape the roof is. And the distance between the beams of the rafters directly depends on this.

single truss system

Shed roofing is more durable and easier to assemble. The thickness of the rafters is selected depending on the type of wood, its strength and the specifics that this or that design has. The step between them can be 60-140 cm. The distance also takes into account whether the structure will be insulated. If yes, then the step should correspond to the width of the insulation.

The thickness of the rafters must be calculated depending on the slope of the roof. For a slight slope of 15-20º, you can use a material with a section of 50x100 mm. For a steep slope of 45º, stronger ones with a section of 50x150 mm are needed.

Gable truss system

If the calculation of the foot step of the frame of a shed or other type of roof is not correct, then the roof can be taken away, and the beams will sag and bend due to the severity of the structure. In this case, simple repairs are not enough, you will have to redo the entire structure. Therefore, it is so important to correctly calculate the distance between the legs of the rafters, depending on the roofing material used: corrugated board, ceramic or metal tiles, ondulin or slate, etc.

Making the roof of the house is an important and responsible task. The integrity of the structure and the peace of the residents will directly depend on the quality of the upper structure. Before starting work, it is necessary to choose the right boards for rafters and other roof details, perform their high-quality pre-treatment and correctly connect them, preparing them for the roofing material.

Roof types

Currently, about ten different types of roofs are used for residential buildings and outbuildings. Some of them are more familiar to us, others are very rare. The main designs are.

Pitched roofs made using direct truss systems:

lean-to;
gable;
four-slope - hip and half-hip (with a ridge) and tent (without a ridge);
multi-forceps:
conical.

Pitched roofs with curved rafters:

semicircular;
hemispherical.

Almost all types of roofs are based on special parts that provide the roof with the necessary strength and give it the desired shape. It's about rafters.

Requirements for the quality of rafters

For the manufacture of rafters, edged boards of various sections are used. The most common parts with a section of 50x150 or 50x200. A bar of square or rectangular section is not used, since it cannot provide the necessary strength to the structure or will significantly make it heavier. Do-it-yourself rafters are always installed on edge. In this direction, the parts are stronger and not subject to bending.

Installation of the truss system of the outbuilding

For work it is better to choose softwood boards. This is due to several of their features:

the presence of resin prevents the formation of rot in the material;
such parts have a relatively low weight, unlike, for example, boards of the same section made of birch;
coniferous material is more affordable, and it is much easier to find it at sawmills.

In addition, be sure to pay attention to such elements in the wood as knots. The presence of rotten drop-down elements, which can lead to a decrease in the strength of the rafter leg in the future, is not allowed.

Preparing rafter system parts for installation

Before proceeding with the installation of the roof truss system with our own hands, we recommend that you carefully treat the surface of all wood parts used in the work.

Pre-inspect the purchased lumber, select the highest quality. Boards with falling knots can be used in pieces, for example, when lengthening or for making racks (headstocks), struts, crossbars and other roofing details. After selecting a sufficient amount of lumber, it is treated with special protective compounds that prevent rotting and burning.

You can apply flame retardants and antiseptics with your own hands in the following ways:

immersion;
brush or paint roller;
spraying.

Each method is good for one purpose or another. After one layer of impregnation has dried, it is recommended to re-treat. It is advisable not to mix formulations for different purposes in the same container.

Choosing the best truss system

Having selected high-quality boards 50x150, and having completed their processing with our own hands, we proceed to the installation of the truss system. Before starting work on the perimeter of walls made of bricks or blocks, it is necessary to lay a mauerlat - a beam that will serve as a support for the lower parts of the rafter legs.

It is fastened with threaded studs recessed into the wall or steel wire laid in the seam of the masonry. In buildings made of timber or logs, the role of the Mauerlat is played by the upper crowns of the log house.

Depending on the size of the span between the walls of the house, we choose the option of installing rafters. There are systems with hanging rafters or layered, based on an intermediate load-bearing wall.

Roof options: 1) With hanging rafters. 2) With layered rafters

The first type of construction has a horizontal transverse beam - puff. In the second, this element is missing. For support, the ridge beam rests in several places on the intermediate wall of the house. This is not very convenient in the case of manufacturing an exploited under-roof space - an attic, but it is optimal for large flights between walls.

Determine the number of roof trusses

To determine the amount of lumber needed for the manufacture of rafters, for example, 50x150 boards, it is necessary to calculate the required number of truss trusses - pairs of rafters connected at the required angle. On average, the span between them is 0.9-1.2 meters or slightly less. The determining criterion is the roofing material intended for use.

So, for ondulin, the manufacturer recommends a rafter installation step of 0.6-0.9 meters, for metal tiles - one of the most common materials in recent years - 0.65-0.95 meters. Of great importance when choosing the inter-rafter distance is the slope angle of the slopes, which depends on the snow and wind load in each particular area.

Having determined the step size, we divide the length of the walls by this indicator and add one, taking into account the installation of gable trusses. We get the number of rafter pairs. Multiplying this number by two, we determine the required number of rafters. We calculate the length of the boards according to the Pythagorean theorem, knowing the same slope angle of the slope and the span of the walls.

We mount the truss system - we collect trusses

Having decided on the number and size of the rafters, you can begin to assemble the roof truss system with your own hands. As a rule, they try to install pre-assembled farms. You can make them both on the attic floor of the house, and on the ground and raise them ready-made.

In any case, a few templates will greatly facilitate the work.

The first of them is a rafter of the required length with ends sawn at the required angle. If necessary, the edges can be cut not in a straight line, but with ledges that facilitate the installation of parts. For example, if the rafters rest on a beam, fastening can be done with steel angles, perforated steel tape, or nails. In all cases, a figured cut will increase the quality of the installation.

The second template is a sheet of plywood with stops nailed at the required angle, into which the upper ends of the rafters are inserted and connected by crossbars - transverse boards with a section of 50x150, providing the necessary rigidity of the rafter pairs. If free space allows, you can use one self-assembled farm as a template.

Installing farms

Do-it-yourself farms are lifted up. Installation is convenient to start with the extreme pairs, called gables. They are installed vertically, controlling the position along a plumb line or a board nailed to the wall of the house, and fix the position with the help of additional slopes. The lower ends of the truss rest on the mauerlat beam or on the log crowns. They are nailed to them with nails No. 100.

Methods for attaching the rafter leg to the Mauerlat

Having fixed the extreme farm, the rest are fixed, observing the span between them. To control this value, you can first cut spacers from a 50x150 board with your own hands and do not measure the distance for each pair. The corners of the roof trusses after their installation are additionally connected with a ridge beam or board. In addition, the crate will help fix the rafters.

let `s talk about construction of a simple gable roof. There is nothing complicated in the design of this roof, and you can easily make it. do it yourself. This type of roof can be used on any other building (house, sauna, outbuilding, garage...).

We begin the manufacture of the roof with taking measurements, making drawings and calculations. There are online services for roof calculations on the Internet.. If you forgot the theorem Pythagoras, then the online calculator for calculating roofing materials will help you. With the help of such a calculator, we calculate the length of the rafters and the corners of the roof. Knowing these parameters, we make sample, according to which we produce the required number of rafters. For the manufacture of rafters, a board 50x150 mm is suitable.

We do not cut the rafters from below to size, but leave them a little longer.

First of all, we install the extreme rafters. When installing the extreme rafters, we check the vertical distance from the upper harness (Mauerlat, ceiling, wall) to the ridge board.

Boards nailed vertically to the walls will help us install the end rafters evenly and safely.

Install (if needed) a beam that will support the ceiling and prevent it from sagging. The ceiling beams will be attached to it from below, and the slopes and supports of the ridge board from above. Also on this beam are installed vertical supports and slopes that support the ridge board. You can make a beam from a board 50x150mm or from a bar 100x150mm.

If the width of the ceiling and its weight with insulation are not large, then you can do without a supporting beam.

Then we install the supports and slopes on the ridge board ( so that it does not sag under its own weight and is fixed from longitudinal movement).

Trim the rafters after they are installed. When all the rafters are installed, we check the diagonals of the slope (they must match exactly), pull the cord and mark the cutting points, and only then we cut all the rafters.

Since metal tiles will be used in this roof structure, we proceed to laying the roofing material ( waterproofing). A waterproofing film is overlapped on the rafters, then a counter-lattice is nailed to the rafters. A 50x30 mm board is suitable for a counter-lattice.

The counter-lattice fixes the film and sets the necessary air gap between the film and the metal tile.

Then we nail the crate to the counter-lattice with a certain step, which depends on the profile of the metal tile.

For the crate, you can use a board 30x150mm or 30x100mm.

We start from the bottom and move towards the ridge, sequentially installing a film-counter-batten-batten.

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