Slate sheet, consisting of a mixture of asbestos and cement, is a fairly economical raw material for roofing, which has a number of undeniable advantages. Strength is the main one: a slate sheet can easily support an adult. It is also characterized by durability: slate does not burn and is absolutely resistant to corrosion. That is why asbestos slate is a priority for developers of small and large construction companies. And this despite the fact that every year more and more various options for the roof. Let's take a closer look step by step instructions How to cover a roof with slate so that you don’t think about it for many years.
Description of the material. Advantages and disadvantages
Asbestos slate is produced in accordance with GOST 30340-95. It is mainly made in sheets of various sizes and number of waves, which is convenient for roofs of various widths. Due to the spread of opinion about the negative impact of the composition, which was not subsequently confirmed, on the human body, manufacturers began to produce slate with chrysotile-asbestos filler.
The bulk of producers are located in Russia, Ukraine and Belarus.
Advantages of using asbestos slate:
- low price;
- increased strength is achieved through reinforcement and a specific sheet shape;
- ease of use and installation;
- excellent noise absorption;
- low thermal conductivity compared to other roofing materials;
- absolute non-flammability of the coating.
Disadvantages of using slate:
- very fragile material when subjected to pinpoint impacts;
- the ability to absorb and retain moisture from the air;
- likelihood of cracking in the heat;
- very heavy weight when compared with a metal profile;
- exposure to ultraviolet radiation and wind reduces the strength of the coating over time;
- growth of lichen and moss on outer surface slate.
How to lift slate onto a roof manually?
At large high-rise construction sites, a variety of construction machines and equipment are available. Therefore, such questions do not even arise there. And the slate is lifted onto the roof in large piles at once.
But in the construction of a private house, using a crane is extremely expensive and not profitable. Therefore, builders got used to lifting slate using a mechanized single or double block, or a mechanical winch. But the winch is convenient for large quantity sheets because it has a low speed.
If you need to lift one sheet, regardless of whether using a block or not, you must tie the slings correctly for a more even distribution of weight. It is better to use natural fiber for ropes.
First, two corners are tied from the bottom, and then they are connected to the center of the top of the sheet. A hook attached to a rope clings to this top and the slate is lifted onto the roof.
If the height of the walls is small, you can use a ladder, like on rails, to lift the sheet to the top.
Correct calculation of slate for the roof
For different types of roofing, different calculations of the required raw materials are used. Let's look at the main methods:
Shed roof
This is a very practical type of covering because it requires much less slate and workers. And installation is easy and quick. Such a roof has a slope on one side, the angle of which depends on the difference in the height of the walls and their spacing. The calculation of the material begins precisely with the angle of inclination. It is recommended to make the slope as steep as possible; in winter, the snow will fall off the roof on its own without requiring your intervention.
On average, the angle of inclination is from 10 to 50. In Russia, it is recommended building codes, build a roof with a slope of 20-30 degrees, and in regions with high rainfall - up to 45.
So, when calculating the exact number of slate sheets, it is important to know exactly the angle of inclination, the width of the roof and its length. These values just need to be inserted into the formula. Where tg of the angle (we take the value according to the Bradis table) is multiplied by the width of the house. For example, a house with a roof angle of 30, a wall width of 4 m, and a value of tg = 0.577. The difference according to this formula is 2.308 m = 0.577 x.
Gable roof
The main thing to understand here is that there is a real and effective width. The real one is calculated from edge to edge on the other side. Effective is the coverage width of one profile, but it will certainly be less than the actual width.
After calculating these indicators, the length of the entire roof is taken and divided by the width of the sheet. Be sure to add an additional 10% overlap. This will be the exact length of the first row.
How many nails do you need for a sheet of slate?
In fact, calculating the amount of slate is not a difficult matter; the main thing is to correctly calculate the area of the roof itself, but questions often arise regarding fasteners. For example, how many nails are needed for a sheet of asbestos slate. Let's figure it out.
Basic rule: to thoroughly fasten a sheet of roofing material, on average, 4 specific nails are required. More is possible, less is absolutely not possible!
Each nail is an additional hole in the roof, which can lead to precipitation leaks. Let’s say for a roof with a slope of 45-90 degrees, the optimal number of nails is 6-8 pieces.
Slate installation. Stages of work
The first and basic rule of roofing is to carry out work only from the bottom up. The rest can be selected individually for each roof. For example, the side from which to start laying the roof. The priority will be the one from which the wind blows most often in a given area.
There are two main ways to lay roofing materials:
- slate fastening with offset;
- fastening slate with cut corners.
And the method of fastening will depend on the shape of the roof. Let’s say that for a roof with a wide slope along the horizontal line and a narrow slope along the vertical line, the first option is best suited. It is more convenient to install a roof with a wide slope in a vertical line using the second method. To ensure an even roof cut line during installation, it is imperative to set either laser level, or nail the rail.
Installation steps:
- The preparatory stage is the calculation of the required materials, purchase and delivery directly to the work site.
- Installation - installation of rafters and construction of sheathing for slate with laying of insulation materials on it.
- The final stage is securing the slate to the sheathing using profile nails. Most main stage, the service life and quality of operation of the roof depend on it.
Overlap when laying sheets
If before purchasing required amount material for roofing works, you have studied in detail the principles of its installation, you should have already followed the main stages.
- Development of a detailed layout of sheets on the sheathing. It is produced at the stage of purchasing materials. This way you will avoid purchasing extra sheets.
- Bringing the sheets to the required shape using a grinder. To prevent the material from crumbling, it should be moistened in advance. Checking sheets for defects.
- Laying slate sheets. Work begins from below. Attach the slate to one of the upper corners of the sheathing, making sure it is flush with the roof. And then fix three more nails in the crest of the wave, at different angles.
- Each subsequent sheet of slate along a horizontal line is fixed in the same way, making an overlap of 1-2 waves.
- Go through the entire row along the perimeter in this way, hammering in four nails.
- The next row begins with an overlap of at least half over the first, continuing this way with each corner.
- So we go through the entire roof slope, do not forget to leave an opening for ventilation. Then the same thing is repeated on the other side. Ultimately, the roof will resemble a chessboard in design.
Laying slate with corners trimmed
This method requires the application of great forces. But the result is worth it, since the roof laid in a similar way, looks perfectly smooth, without unnecessary gaps, which extends its service life significantly. And the consumption of used sheets is an order of magnitude lower.
List of main stages:
- Draw a roof plan; further calculations on materials depend on the correct drawing. Calculate the required amount of material.
- Decide on the side to start laying the roofing material. In fact, it doesn’t matter what suits you.
- Adjusting slate sheets for installation. The exact dimensional angle cut on the sheet is 103mm at the top and 130mm at the side.
Be sure to consider the following aspects:
- the very first roofing sheet in the bottom row and the last one in the top are never cut on each slope.
- processing sheets of the lower first row are cut according to the direction.
The second row is laid in accordance with the following order:
- The 1st sheet is the corner from the bottom left;
- the sheets in the middle will go lower on the left and upper on the right;
- the outermost leaf is the top right.
The last row goes the same way, but the outer profile is not cut to get a complete picture of a flat roof.
How and with what to attach slate to the roof? Mounting options
The most reliable fixation of a slate sheet is made with a nail; it prevents the sheet from deforming and leaves it motionless. There is one nuance in fastening with nails: to securely fasten and not allow leaks, the nail must be placed along the highest point of the wave and strictly along a vertical line.
The length of the nail should allow it to pass through two sheets of roofing and go far into the sheathing. Typically, nails with a length of 7 to 12 cm are selected. A special feature of roof nails is the increased head width of up to 14mm. The nail head is also made of galvanized steel to avoid corrosion. Although the best are considered to be roofing nails made entirely of galvanized steel.
Roofing nails are made in two types:
- smooth;
- ruffled.
When choosing the first ones, it is necessary to take longer ones, so that after driving them into the roof, the protruding tip can be bent. This will prevent them from loosening during operation and extend their service life.
When choosing the second option, there is no need to take a larger size, since the nail has special notches that securely fix the fasteners in the sheathing. The only disadvantage of these nails is that they will be very difficult to dismantle in the future.
The roofing nail must have an elastic gasket that is not exposed to external factors. The shape of the washer completely follows the curve of the slate sheet, which ensures complete sealing of the coating.
Roof fastening is allowed in the usual way construction hammer, but in this way you can ruin the slate sheet, leaving the smallest cracks on it, which in the future will not affect its service life for the better.
It is better for these purposes to use a drill with a diameter 2 mm larger than the fastener. When driving, you should hold the nail with pliers so as not to damage the slate sheet with an accidental blow. The impact force also needs to be calculated so as not to deform the wave of the sheet with the nail spacer.
The use of self-tapping screws in fastening slate sheets
It is possible to secure slate sheets to the sheathing without using nails, using self-tapping screws. This method has its advantages:
- increased strength due to hardening of the metal of the screws;
- a huge selection of screws according to the length and shape of the cap;
- wide range of colors of self-tapping screws;
- The screws are supplemented with a special seal that reliably seals the roof surface.
When fastening with self-tapping screws, you will also need to make a hole with a drill. The self-tapping screw is driven into the hole with a screwdriver. This significantly reduces the time it takes to cover the roof.
Installation of ridge and wind strip
No less attention should be paid to the ridge and wind strips, since these elements bear the most high pressure, ridge guarantees the tightness of the slate ends on top of the roofs. The end one reduces the pressure on the slate sheets on the sides, which is why it got its name.
Installation of the ridge, main nuances:
- before fixing the ridge, it is necessary to complete the ventilation space under the roof;
- to avoid snow drifting under the ridge, all smooth slopes are covered with special strips;
- work should begin from the planks outside the end strip with an allowance of 20-30cm;
- be sure to overlap at least 10cm on each side;
- To facilitate the work, bars of the required size are secured under the workpiece.
Installation of the end strip:
- the end strip is fixed to the level along the first wave of the entire row, while covering the corner;
- attach it with self-tapping screws on the side, top and on the ridges;
- join them with a 10cm overlap;
- All joints of the planks are sealed with a silicone mixture specially designed for roofing.
When attaching the end strip, make sure that it covers the end of the wave so that sediment does not leak inside.
Installation of snow guards
Basic principles of fastening all types of snow guards:
- To secure this device, it is necessary to strengthen the sheathing.
- fasten snow guards flush to the lower slope of the roof;
- the minimum distance to the roof cut from the snow guard is not less than 400 mm;
Although traditional asbestos-cement slate cannot be classified as an innovative material, it is being replaced by more modern coatings, and in many European countries they abandoned it completely, for Russian market it does not lose its former popularity, as it is quite durable and reliable. In this regard, the question is how to produce correct styling DIY wave slate , is still of interest to homeowners. Moreover, this material can easily be transformed by painting it in the chosen color, which will be in harmony with the color of the facade. Therefore, slate can be used not only for covering country houses or outbuildings, but also for full-fledged residential buildings.
However, in order for the slate to serve for more than fifty years, as the manufacturer promises, it must be laid correctly, that is, some nuances of this process must be taken into account. First of all, it must be said that slate is not such a universal material as many people think, since it is mainly suitable for covering one and two pitched roofs with a slope of at least 15 degrees. If you plan to lay this covering on a flatter slope, you will have to install a sheathing under the covering according to special rules, reliable membrane or roofing material waterproofing, and also increase the mutual overlap of the sheets.
Types of slate and its sizes
Slate was originally called roofing material, made from cement mortar and asbestos fibers, which act as a reinforcing component, giving the sheets durability and strength.
Since the wave version of the sheets has higher mechanical strength, rigidity, and is more resistant to external influences, this form was taken as the basis for the manufacture roofing sheets from other materials, such as ceramic plastic, cellulose fibers impregnated with bitumen, Various types polymers and sheet metal. Therefore, these materials also began to be called, with reference to the material of their manufacture.
Asbestos cement slate
The current GOST defines several standard parameters traditional asbestos-cement wave slate, differing both in the number of waves and in the length of the sheets. But in practice, material with a length of 1750 mm is most often used, as it is the most convenient to use. In turn, it is also divided into several types.
- The six-wave sheet has dimensions of 1750 × 1125 mm and a thickness of 6 or 7.5 mm. Its weight is respectively 26 or 35 kg. The wave pitch is 200 mm, and its height is 54 mm. Such sheets are considered the most durable of all asbestos-cement wave slate options, so they are most often used to cover industrial buildings.
- The seven-wave sheets have dimensions of 1750×980 mm, a thickness of 5.8 mm and a weight of 23.2 kg. The wave pitch and height are already smaller - 150 and 40 mm
- The eight-wave version is a sheet measuring 1750×1130 mm, thickness 5.2÷5.8 mm, weighing 23÷26 kg. The step and height of the wave are the same as for the seven-wave one. It is this type of slate that is most often used in residential construction.
Infrequently, but still, sheets of a more “modest” format are also used - 1200 mm long, 680 mm wide, with the same 40 mm wave as eight-wave slate, and weighing only 9 kg.
The technical documentation may contain letter designations wave slate parameters. To figure this out, you should pay attention to the diagram below, where: B – width; L – sheet length; S – distance between wave crests; t—slate thickness; h – height of the ordinary wave; h1 and h2 are the height of the overlapping waves.
GOST also established a standard marking for wave slate in the form of a fractional value: the numerator is the height, and the denominator is the wave pitch, for example, 54/200 or 40/150.
Before purchasing this material and proceeding with its installation, you should have an idea of its positive qualities and existing shortcomings.
- The advantages of asbestos-cement slate include:
- relatively affordable cost of the material;
— sufficiently high strength, thanks to the reinforcement and characteristic shape of the sheets;
— ease of processing and roofing work;
— good noise absorption;
- low thermal conductivity - the roof will not heat up in the sun as much as one covered, for example, with metal corrugated sheets or metal tiles;
- non-flammability of the material.
- The disadvantages of such slate are its following properties:
— fragility under point and impact loads;
- hygroscopicity of the material - it can become saturated with moisture;
— possibility of fracture due to sudden temperature changes;
- quite heavy weight compared to other types roofing coverings, which complicates the transportation and lifting of sheets to a height;
— gradual decrease in strength under the influence of ultraviolet rays and wind (weathering);
- asbestos-cement surface with high humidity air becomes a favorable environment for the appearance of colonies of moss and lichen;
— asbestos-cement slate is not an environmentally friendly material, mainly due to the content of asbestos fibers in its composition, which is why European countries decided to ban products containing asbestos.
In fairness, it should be noted that the carcinogenic properties of this roofing coating are too exaggerated. And in order to reduce the amount of asbestos dust that appears during weathering, as well as to protect the roof from the appearance and development of moss, fungi and lichens, it should be painted or covered with drying oil every 4-5 years.
Modern varieties of slate
IN last years More and more new types of slate made from various materials, and they are quite worthy of attention.
Ondulin
Ondulin, which is also called bitumen slate or Euroslate, began to be produced in Europe when the technology of reinforcing bitumen with cellulose fibers appeared, which hold together, impart rigidity and prevent cracking of the coating due to temperature changes.
Despite the fact that slate is not as popular as, for example, metal tiles, it has good technical performance. Besides good quality This material is cost effective compared to many other roof coverings. Therefore, it is worth familiarizing yourself with slate, its selection and installation in more detail. This article will present different ways laying this material.
Types of slate
Before laying slate, you should understand its varieties. This material differs in shape and composition.
Form slate changes depending on the number of waves. This affects the width and length of the sheets. You can see the different shapes more clearly in the table.
| Name | Number of waves, pcs. | Wave pitch, mm | Wave height, mm | Sheet length, mm | Sheet width, mm | Sheet thickness, mm | Weight of 1 sheet, kg |
|---|---|---|---|---|---|---|---|
| Six-wave | 6 | 200 | 54 | 1750 | 1125 | 6/7,5 | 26...35 |
| Seven-wave | 7 | 150 | 40 | 1750 | 980 | 5,8 | 23,2 |
| Eight wave | 8 | 150 | 40 | 1750 | 1130 | 5,8 | 26,1 |
These types of slate comply with GOST and are used for pitched roofs. To calculate the amount of material, the roof area is calculated, then the required number of sheets is selected.
More sheets of slate will be required for a wide wave pitch (for example, for a six-wave). In this case, with vertical overlap, more material will be required.
By composition slate can be cement-fiber or asbestos-cement. The first and second options are suitable for installation on the roof. But it should be borne in mind that asbestos in the composition increases the strength characteristics of the material, so it is preferable to use the second option.
Preparation for installation
When the required type of slate has been selected, you can begin preparatory work. They include:
- Dismantling the old covering.
- Preparing the work site.
- Preparation of material.
First of all, you need to do dismantling the old coating. It is necessary to choose a period when the weather will be dry, without rain. It is better to remove old slate with an assistant. The sequence of dismantling the material should be the opposite of its installation.
Then a free area is allocated where the preparation of material. The area should be level so that it is convenient to saw and measure sheets.
Preparation material consists of processing slate sheets. The material must be impregnated with a special composition that has water-repellent properties. For this, paint is used: alkyd, water-dispersion, acrylic. This procedure will level the surface of the slate, filling microcracks. Due to this, water will drain from the roof faster.
Laying methods
After preparing the main material, you need to decide on the method of laying the slate. The most commonly used schemes are:
- No offset.
- With offset.
The first method is as follows: when laying a horizontal row, the lower corners of the sheets are cut off. You need to cut from the side that will overlap the next horizontal row.
The offset method looks like this: the rows are laid offset relative to each other. This method is good because it can prevent more than 2 sheets of slate from joining at one point.
Required tools and materials
To install slate, you must purchase the following tools and materials:
- Thermal insulation.
- Waterproofing (polypropylene film).
- Rafter.
- Construction tape.
- Wooden beams for sheathing (60x60 mm).
- Antiseptic.
- Galvanized nails.
- Self-tapping screws.
- Construction stapler.
- Building level.
To calculate the amount of slate, you should calculate the number of rows that will fit on the roof slopes. When calculating, you need to take into account that the material will overlap, so a margin of about 10% must be added. To determine the number of sheets in 1 row, you need to measure the length of the roof, then divide this value by the width of the sheet.
If there are 6 sheets in a row, and the number of rows that will be installed is 3, then a total of 18 sheets will be needed. It is always necessary to purchase material in excess, taking into account that it will be cut off or may break off during installation.
It is best to use self-tapping screws for fastening slate. To calculate their length, you need to take the thickness of the sheathing, add the thickness of the slate and the height of its wave.
After preparing everything necessary, the slate is laid.
Laying technology
The slate laying technology consists of several stages:
- Installation of thermal insulation.
- Waterproofing installations.
- Installation of sheathing.
- Slate laying.
Installation of thermal insulation can be skipped if it is not necessary. But those who want to insulate the top floor will need to complete this step. To do this, thermal insulation sheets are laid on the roof. A waterproofing film is mounted on top of it, the sheets of which are laid overlapping.
The waterproofing film should be laid with the fleecy side facing inward. Due to this, a moisture barrier is created and liquid will not penetrate into the thermal insulation.
To secure the waterproofing you will need construction stapler, which needs to be installed on the roof. If necessary, you can perform 2-layer waterproofing, which will increase additional protection from moisture.
The next stage is installation of the sheathing. For this purpose they use wooden beams, which must be treated with an antiseptic. It is forbidden to use wet material, otherwise after drying it will decrease in size and become deformed.
To install the sheathing, you must perform the following steps:
- Calculate the sheathing (depending on the size of the slate).
- Install vertical bars on the slopes.
- Install horizontal ones on vertical ones.
- If there is a pipe, then bars are additionally nailed around it.
It is necessary to ensure that the distances between the bars do not differ. On average, the distance between the beams should be about 50-60 cm. If high-quality slate is used, then it is allowed to maintain a distance of 80 cm.
After installing the sheathing, the installation of slate on the roof begins.
Laying slate. Step-by-step instruction
Pre-measured and cut slate sheets, as mentioned above, are treated with a water-repellent compound. The slate should be prepared in advance by marking it. Holes are marked and drilled.
The holes for attaching the slate to the sheathing are made larger diameter than the diameter of the screw.
Attaching the slate to the sheathing is done in order. In order to determine which side to start laying from, it is necessary to determine the direction of the wind and do the installation against its direction. Due to this, the wind will not blow into the cracks, which will not lead to them being torn out of the sheets in the future.
The most common method of fastening slate is offset. This method prevents more than 2 sheets from joining at one point, so it is recommended to use this type of fastening.
When attaching the first bottom row, you must follow the instructions:
- Fasten the first sheet.
- Overlap the first one with a second one. Do the overlap in 1 wave. But to increase strength, the overlap can be done in 2 waves.
- Place the third and subsequent sheets on the second one.
All sheets should be secured to the sheathing. If you pre-drill the holes, installation will be much easier. When tightening the self-tapping screws, you must adhere to the following rule: you cannot tighten it too tightly, otherwise, after a change in temperature, the slate will slip slightly and further crack. In this case, you cannot leave a large gap, because in the future the fastening may unwind. The ideal solution there will be a gap between the cap and the sheet - 2 mm.
Fastenings should be made in several places: in the second and penultimate waves. For example, if an eight-wave sheet is used, then the screws are installed in the second and seventh waves.
After installing all the sheets of the first row, you can begin installing the second row. The first sheet of the second row must be shortened by 2 times and secured to the sheathing. The second sheet and subsequent ones are mounted in one piece. Thus, the sheets of the first and second rows are mounted in a checkerboard pattern.
The last sheet of each row should be carefully measured and cut to ensure even edges.
In order to cover the roof as efficiently as possible, it is recommended to follow the following advice from professionals:
- When choosing sheet parameters, adhere to GOST 30340-95.
- Use high-quality timber for sheathing.
- Be sure to do waterproofing.
- If you have no experience in roofing, it is best to use the simplest method of installing slate - with a shift, which was described above.
- When making fasteners, you should not nail the slate too hard, otherwise it will crack over time.
- When working at height, you must use safety nets (use safety ropes).
Before starting work, be sure to carry out necessary calculations, pick up quality material, otherwise the work of covering the roof will be in vain. After installing the slate, you need to monitor its condition: clean it from dirt, snow, and ice in a timely manner. Proper care increases its service life.
This video will help you learn how to properly lay slate on the roof of a house. All stages of installation are presented.
Laying slate on a roof does not take much time if you follow all the steps step by step. Due to modern technologies Transparent and colored options are created, which makes it possible to make the roof of a house not only strong and durable, but also transform it from an aesthetic point of view.
Despite the fact that many new roofing coverings have now appeared, asbestos-cement slate is not yet going to lose its position. Many people do not know how to properly lay slate. Let's consider the methods and technology of laying slate with cutting corners with your own hands.
Types of slate
Before talking about methods, let's briefly look at the types of this material. Currently, manufacturers produce corrugated and flat sheets of asbestos-cement slate. Each of them is intended for a specific type of work. As a rule, flat sheets are laid on the roof if its slope is at least 35°. This is explained by the fact that with such a slope the load from snow will be less, because flat sheets do not have stiffeners, like wave slate, they break more easily. But corrugated sheets should not be installed on a roof where the slope angle is less than 20°, so that water at the joints does not penetrate into the under-roof space.
If the roof slope is small, then better protection from rain, before laying the slate, you need to lay a waterproofing carpet made of ordinary roofing felt or other hydro insulating material. The dimensions of asbestos-cement sheets also play a big role, since the pitch of the sheathing and the cross-section of its elements depend on this. After all, with a reinforced profile or, for example, a six-wave profile, it is different, therefore the sheathing should be of a different section.
Preparing to lay slate
Before laying slate, you need to prepare the base where it will be mounted. To do this, a sheathing of boards or bars is placed on the exposed rafters. If a board is used, its dimensions are usually 15–20 cm in width and 2–2.5 cm in thickness. Lumber can be used unedged, if you can buy it edged board No. The main thing is to sand the edges and impregnate them with antiseptics and fire retardants to eliminate the risk of rotting and fire. If bars are used, their cross-section should be approximately 5x5 cm.
When purchasing lumber, you need to carefully inspect each board or block and immediately reject those that are crooked, with traces of wood-boring beetles, or with a large number of knots or bluish areas (they indicate the beginning of rotting). The wood must be dry, otherwise it will simply warp on the roof and the horizontality of the laid slate sheets will be in question.
Before laying slate, it is important to strengthen the roof overhangs and ridge with boards in two rows, without any space between them. The sheathing bars are placed along the ridge perpendicular to the rafters with such a step that the slate sheet rests and is attached to at least three points along its length. For asbestos cement sheets standard size the distance between the sheathing bars or the center of the board should be approximately 55-60 cm. If it is not possible to lay a multiple number of sheets and trimming is required, then you can reduce or increase the length of the roof overhang.
After installing the sheathing, according to the rules for laying slate, it is necessary to waterproof it with roofing felt. Strips of this material can be laid both across and along the roof slope. It all depends on the magnitude of the slope of the structure. But without fail, the edges of the strips must overlap each other by an amount of 10-15 cm. The smaller the roof slope angle, the greater the overlap made when laying roofing felt or other insulating material. The roof ridge is also covered with roofing felt.
Slate laying methods
It is possible to make a slate roof using two methods: with displacement of sheets, otherwise called “staggered”, or with cutting off corners. The method of displacing slate sheets relative to each other is simpler and is most often used when installing a roof made of asbestos-cement sheets. The disadvantage is the high consumption of material due to the fact that cutting to the length of the outer sheets is required.
In addition, it is necessary to ensure that the laid material is horizontal relative to the ridge and the lower overhang of the roof. Laying slate staggered is recommended when the roof slope has big sizes horizontally and small vertically. In this case, the sheet is shifted by one wave, and the eaves overhang is missing.
The second method is to trim the corners of each sheet being laid. This is a more labor-intensive process, but the consumption of roofing material is significantly reduced. This method is used if the roof slope is horizontal small sizes, and the vertical size is significant. It is necessary to ensure that there is no joint between four adjacent sheets of slate in one place. The instructions for installing slate with your own hands indicate the correct cutting of corners. When laying roofing material from left to right, the left corner of the sheet is cut off; when laying sheets from right to left, the right corner is cut off.
In order to lay slate correctly, you need to know some nuances when working with this material. First of all, they prepare the sheets for installation - inspect them for integrity, drill holes for further fastening with nails. At the same time, it must be remembered that drilled holes should be 2-3 mm larger than the diameter of fastening nails or screws. It is better not to cover a roof of complex shape with a large number of grooves and valleys on your own.
With a slight slope of the slope, less than 20°, it is carried out by fastening the sheets in the second wave from the edge. It is not recommended to pierce slate with nails to prevent it from splitting at the fastening point. You need to drill holes with an electric drill or by hand. It is better to trim corners with an angle grinder, colloquially called a “grinder”, or a hacksaw for metal. When using a grinder, the cut is smoother and does not chip, and much less time is spent than when working with hand tools.
Special nails must be used, with a metal washer, which will prevent water from entering the under-roof space at the point of fastening. If self-tapping screws are used, they must have special thermal washers.
Now it is possible to make a roof from slate sheets of any color, and it is better to choose screws to match the roofing material. In places where sheets join, it is recommended to lay a sealing cord or use special mastic, silicone sealants. Before laying the first row of slate on the roof overhang, it is necessary to tighten the horizontal cord, this will make the work easier. The prevailing wind direction in the area will tell you which side to start laying from.
It is not recommended to fasten slate sheets too tightly to the sheathing, between the sheet and wooden element there should be a small gap. But the number of nails per sheet is determined by the condition of the wood of the rafter system, in particular, the sheathing. Wood that has served for a sufficient period of time will require more nails or screws. The asbestos-cement sheet is fastened into the upper wave of the sheet. Using self-tapping screws when installing slate will make the fastening stronger. This is especially true for those regions where strong winds blow.
The construction market is flooded with roofing materials for every taste and budget, which we had not heard of a couple of decades ago. At a time when stores did not have such abundance, slate came to the aid of summer residents under construction. This one is affordable inexpensive material It’s too early to “retire”, since it is difficult to find an equivalent alternative among materials of the same price category. If you want to cut construction costs in half, read this article on how to properly cover a roof with slate.
Slate is a sheet roofing material with wavy or flat surface, which is made from asbestos cement by molding. Unpainted slate is light gray, but manufacturers add pigments to it, painting it in different colors. In assortment construction stores you will come across slate sheets consisting of 6-8 waves, according to the standard, the length of which is 1.75 m. GOST for this type of construction product regulates the thickness of the material - it lies in the range of 5.8-7.5 mm for different types sheets. Before covering your roof with slate, get to know its advantages:
- Convenience and ease of installation with your own hands. Even a person without construction experience can lay slate. This does not require special skills or expensive tools. You can cut the sheets using a regular hacksaw or grinder, and fix them with slate nails or self-tapping screws.
- Reliability. Do-it-yourself slate roofing is a reliable way to protect the attic from moisture, cold and wind. This material is not afraid of hail or falling branches from nearby trees, because they will not harm it.
- Fire resistance. The fireproof qualities of asbestos cement are another reason to use it as a roof covering, because the chimneys of heating appliances, fireplaces and stoves lead to it. Slate roofing is especially relevant for baths, the chimney pipes of which are heated to a temperature of 750-850 degrees.
- Long service life. If, before covering the roof with slate, you treat rafter system fire retardant and antiseptic, the service life of the structure will reach 40-50 years.
- Affordable price. Average cost of 1 sq. m of slate roofing, taking into account the price of fasteners and waterproofing, is 200-250 rubles, if you do the work yourself. If you involve a hired team of professional roofers in the process, costs will increase by 50%. But even with the cost of paying workers, it is half cheaper than metal tiles or ondulin.
Important! Slate has two special features that need to be treated with attention: despite its heavy weight, it is a fairly fragile material. Therefore, when purchasing, be sure to check the integrity of the sheet, make sure that there is a paper spacer between them. For ease of work at the construction site, prepare a level place for unloading and storage in advance by spreading film there.
Requirements for the rafter system
Before covering the roof with slate, the roof rafter system should be properly prepared. The fact is that this roofing material has a significant weight compared to modern analogues. The weight of one sheet can reach 30-35 kg, and this is a serious load for the elements of the supporting frame. When creating a roof project, follow these rules:
- For the manufacture of rafter legs use boards with a section of 60x150 mm or thicker. The best option boards of the highest quality 100x150 mm, the humidity of which is not higher than 15-16%, are considered.
- Wooden blocks are used to make the sheathing. coniferous species 6x6 cm in size, which will not break under the sheets.
- If you nail the sheathing yourself, make sure that each layer of slate is supported by two or more pieces.
- The distance from the edge of the sheet to the nearest sheathing bar should not be less than 150 mm.
Note! The angle of the roof slopes is of great importance. Manufacturers recommend laying slate on roofs with a slope of 22 degrees or more. For single-pitched and gable roofs use slate, even if the angle is 5-15 degrees. However, the smaller the angle, the denser the sheathing should be. For the minimum permitted values, a solid base made of moisture-resistant plywood is used.
Calculation of material quantity
Before covering the roof with slate, you should calculate how much material is required. To estimate the required number of sheets, so as not to overpay for unnecessary balances, perform the calculations as follows:
- Take a tape measure and measure the length of the roof along the eaves. If the roof is still in the project, then take this value from the drawing. Divide the length of the eave overhang by the width of the slate sheet you will use. By increasing this figure by 10% and rounding up to whole numbers, you will get the number of sheets in one tier of the layout.
- Measure or find out from project documentation the length of the roof from the ridge to the edge of the eaves. To calculate the required number of rows, divide this value by the length of the sheet and add 13%. The surcharge compensates for the overlap between the sheets.
- By multiplying the number of sheets in one row by the number of tiers, we determine how much material is required to cover the slope. If the roof has two symmetrical slopes, the result is doubled.
Note! In case the sheet is damaged during cutting with your own hands or during transportation, it is better to have a supply of material, 10% is enough. The asbestos dust generated during this process is dangerous for the lungs, so you should only work in a respirator moistened with water.
Installation principles
The junction of the four corners that is formed as a result is the main difficulty of installation. To avoid pieces of material breaking off, deformation, and water or wind entering this vulnerable area, there are two proven methods:
Important! Asbestos cement, from which most types of slate are made, changes size with changes in humidity and temperature. Therefore, in order to prevent damage to the integrity of the sheet, holes with a larger diameter than the size of the screw or nail are drilled at the fastening points. The fasteners are not screwed in all the way, leaving a gap that compensates for fluctuations during heating.
Video instruction
