Asbestos-cement corrugated slate is a traditional roofing material that has dominated in our country for many decades. Technical parameters differ significantly from modern roofing materials; knowledge of operational characteristics is required in order to avoid mistakes during roof installation.
About 20 years ago, an attack on asbestos-cement slate began; regulatory organizations in developed world countries banned the production of such slate. The reason is that it contains asbestos, which is considered a dangerous carcinogen. Our country resisted for several years, and then also limited the use of such slate. Consumers do not understand why houses with such roofs have stood for many decades, and their residents have not seen a surge in cancer cases? One gets the impression that the bans are caused not by concern for public health, but by the competition of roofing material manufacturers.
Why? Asbestos is indeed used to make slate, but not the kind that accumulates in the body (amphibole) and provokes the development of cancer cells, but the one that is safe for health (chrysotile). Chrysotile is acid-soluble and is excreted from the body after a short time. In addition, the substance can enter the body only during cutting with a grinder or making slate at a factory; house coverings, even theoretically, cannot pose any danger. Wave slate is produced in accordance with the provisions of GOST 30340-95.
| Slate parameter | Short description |
|---|---|
| May have 6–8 waves. Currently, eight-wave slate is most often used; it has the largest usable sheet area with the same dimensions. Due to this, the cost of the roof is slightly reduced. | |
| Thickness 5.8mm, 6.0mm and 7.5mm. The higher the wave, the greater the thickness must be, otherwise the sheets may self-destruct. | |
| The length of all sheets is the same, the width ranges from 980–1130 mm depending on the number of waves. | |
| The weight of one sheet is 23.2–35 kg, the weight per square meter is up to 29 kg. This should be taken into account during the design and manufacture of not only the rafter system, but also the walls and foundation of the building. | |
| The maximum bending strength is 16 mPa, this figure is much lower than that of modern roofing materials. Another drawback is that slate is fragile and does not withstand shock loads. | |
| If the manufacturer's requirements are met, the guarantee is 40 years, but in practice, roofs under slate are used for a longer period. |
You can find a fairly large list of advantages of wave slate, but experienced builders confirm only two: relatively low cost and long service life. The second advantage is possible only if the recommendations for laying slate are fully followed and there is no hail during its operation. After a hail storm, the roof will have to be completely replaced; the roof becomes like a sieve with huge holes.
There are quite a few of them; before making the final choice of roofing material, you should familiarize yourself with them all. This refers not only to technical parameters, but also to objective difficulties during installation and operation.
Specialists with little practical experience can glue bitumen shingles or screw on metal coverings; only experienced roofers can work with corrugated slate. The material does not cut well, it breaks under minor loads, you must have experience driving slate nails, etc.
In order to protect inexperienced craftsmen from annoying mistakes, we will tell you what not to do when installing corrugated slate on the roof.
The design look of slate roofing does not satisfy many developers; some of them try to paint the surface of the sheets in the hope of getting a beautiful roof. Doing this is strictly prohibited.
Why? Painting yourself will never provide an even surface finish. Some places will be saturated, others will be pale. On freshly painted slate the difference is not noticeable, but after a few years the roof of the house will become mottled, with dark and light areas of various sizes and shapes appearing on it.
Today we sell industrial painted slate. It is painted using two methods: dyes are added to the mass during production or the surfaces of finished products are painted. The first option is much better, it is more durable, and chips are not noticeable on it. But the price is higher, you have to pay for quality. For painting, special dyes are used that penetrate deep into the slate and are resistant to harsh ultraviolet rays.
The distance between the sheathing slats is selected depending on the angle of inclination, but for most gable roofs a universal condition must be met - each sheet must rest on at least four slats. The sheathing must be perfectly flat, stable and durable. Before starting work, it is recommended to check these parameters, walk on the roof, and shake it with your hands. You cannot level the plane of the slopes with slate sheets; in this position they are under constant tension. Slate is quite fragile; under the influence of prolonged efforts, albeit insignificant, it does not deform over time, but cracks.
Only amateurs drill holes in slate for fixing. This method of laying sheets takes a lot of time; in addition, it is difficult to work with a drill, and it is difficult to screw in self-tapping screws.
Professionals nail the sheets with slate nails.
There is no need to seal anything additional; you should not use silicone or rubber gaskets.
There is no need to be afraid of leaks and rust; slate nails have been used for decades and no problems have arisen because of this. The hole is made at the crest of the wave; water does not flow there.
Slate sheets overlap in one wave. In order to make the joints less noticeable, the last wave of each sheet is thinner than the rest.
It is on this that the material is marked. During installation, the inscriptions must be covered with the next sheet. This indicates the correct position of the roof.
Nails are always driven only into a single sheet, the material is durable, the lock holds perfectly even without special fixation. If you have no experience driving nails, then you need to practice on unnecessary pieces of roofing. Within a few minutes you will gain experience and confidence, nails will be driven in without problems.
Due to the fact that the material is very thick, problems may arise in areas of overlap. To improve the quality of sheet laying, two methods are used.
The sheets are laid in one line with the corners trimmed. It should be noted that trimming corners is done more for the appearance of the roof than to improve performance characteristics. If trimming is not done, then where the four sheets overlap, the latter protrudes slightly. The reason is the large thickness of the material. During trimming, two corners are removed and the plane is leveled. It is believed that if pruning is not done, snow or water may blow into this gap. Practice shows that such statements have no basis. The large overlap of sheets (at least ten centimeters) and small gap sizes (no more than 4–5 mm) prevent snow and rain from blowing in. But this technology is recommended by building codes, it is better to adhere to it.
Step 1. Check the condition and dimensions of the rafter system. As we mentioned above, the mass of the coating is large, the rafter system must be strong and stable.
Step 2. At the bottom of the rafter system, nail a board or stretch a rope. The sheets will be aligned using these elements. It is better to use a board; it not only controls the position, but also serves as a stop for sheets, and is much more convenient to work with. After finishing laying the slate, the board is dismantled.
Step 3. Prepare your tools. You will need a hammer, a grinder with a diamond blade, and nails. If desired, apply sealant to the caps.
Polyurethane sealant
You can find advice to screw slate sheets with self-tapping screws into pre-drilled holes. Professionals never do this. This method only wastes time and money and has no real operational benefits.
Practical advice. The waves should be blocked on the leeward side.
Step 4. Fix the first row of slate, do not forget to align each sheet with the cornice. The amount of overhang depends on the type of drainage system. The overlap is done on one wave, the inscriptions are covered. Slate nails are driven in through two waves; 10 pieces are required per sheet.
In corner places you need to trim the second and third sheets, the first and fourth ones should remain intact. How to trim sheets correctly?
If you wish, you can drill a hole for each nail with a diameter of 0.1–0.3 mm larger than the diameter of the nail body. Coat the back side of the cap with sealant and only then fix the slate. This technology enhances the strength and tightness of the roof fastening. The fact is that a hole punched with a nail has one drawback - on the back side of the slate it increases in diameter and looks like an inverted cone. As a result, the thickness of the slate near the hole decreases, which has a negative impact on the strength of the fastening of the roof to the sheathing.
In theory, the rationale for using a drill sounds correct, but in practice it's simpler. Cordless drills appeared not so long ago, but roofs made by the old method with a hammer without drilling still stand. The large diameter of the cap completely covers the small cone on the back side of the slate.
Practical advice. To move along the roof slopes, be sure to make a special ladder. In total, it will take no more than an hour, but working with it is not only convenient, but also safe. The ladder can be welded and metal or used waste lumber.
Step 5. Secure the ridge row; if the roof is warm, then there should be a gap of at least five centimeters between the slopes in the ridge. This is necessary to ensure effective roof ventilation.
Nail the ridge, windshield and eaves boards. You can make a ridge yourself from galvanized steel or buy a factory made one from asbestos cement. Which option to choose is up to each developer.
For example, we took the simplest gable roof. If it is more complex, then it is necessary to make valleys, various connections to walls and chimneys.
Important. Always try to follow safety rules, work with insurance, and make devices for comfortable movement on the roof. It is strictly forbidden to carry out high-rise construction work alone; you should not risk your health.
Remember that covering a roof with slate is much more difficult than with any other roofing materials. As for the design, it hardly meets the modern requirements of developers; such coatings are best used on various extensions. Developers have no complaints about reliability and durability.
The laying of the slate is completed, the installation of the drainage system can begin.
The weight of one sheet can reach 35 kg; quite a lot of effort has to be made to deliver the material to the house. To facilitate the process, it is recommended to make a simple device.
Step 1. Select two slats of appropriate length. The parameters of the slats are approximately 50x50mm; these dimensions will allow them to fit into the waves of slate and hold it in the desired position. The length of the slats should be approximately 1.5–2.0 m greater than the height of the lower slope of the rafter system. Due to this, the slats can be installed at an angle of approximately 60°–70°. At this angle it is much easier to lift the sheets - there is minimal friction between the slate and the lumber. In addition, the large angle greatly reduces the load on the slats and minimizes the likelihood of them cracking during sheet transportation.
Step 2. To fix the sheet, you can make a special grip. This is an ordinary block approximately 20 cm longer than the slate. The edge of the sheet is supported at the lower end, and a rope is tied to the upper end.
The slate is placed on the slats so that the waves are in place. The gripper catches on the lower end and is pulled onto the roof by the rope. To ensure that long slats do not change their position, it is recommended to fix them together with any pieces of boards.
If you don’t want to waste time on devices, you can place two ordinary boards at an angle and lift the slate with a rope. To do this, you need to wrap a rope around the slate on both sides, and fix the lower end with a hook to the upper vertical one. If you have experience and throw the rope in the middle of the sheet, then when pulling it out it will not go anywhere.
Previously, cutting sheets was a big problem. Holes were first made on the surface using nails, a chisel or a carpenter's hammer with a sharp nose. The process was difficult and long, often the slate cracked in the wrong place. For cutting, a hand saw with fine teeth was sometimes used, but after several sheets they became dull and had to be sharpened again. Only with the advent of grinders and diamond blades did the cutting process become much simpler.
What requirements should be observed when cutting slate?
It is advisable to do all the cutting on the ground, only to assemble the roof on the roof.
Angle grinders (grinders)
Today, the choice of roofing materials is simply amazing in its diversity, but despite this, slate still occupies one of the leading places. So owners of private houses will probably be interested in how slate is laid on the roof.
The most common option is corrugated asbestos cement sheets, which cover most houses. Their advantages include: resistance to temperature changes, fire resistance, fairly long life, ease of processing. The disadvantages of such slate are increased fragility, it is very easy to damage even with a slight blow, and large weight, which significantly complicates roofing work. In addition, there is an opinion that the asbestos contained in it is harmful to health, but studies have not confirmed this.
There is also so-called asbestos-free paper slate. It is inferior to its brother in terms of resistance to mechanical loads. However, its durability, moisture resistance, lightness and flexibility make it possible to use it, unlike its asbestos counterpart, even on roofs with a fairly weak frame. For the roofing of industrial premises, it will be important to familiarize yourself with how to cover the roof with slate made of plastic or metal. They are distinguished by good wear resistance, lightness, strength characteristics and environmental safety. In addition, their color range can satisfy the needs of even the most demanding consumers.
There are two main methods for laying slate on a roof. The easiest and therefore most common method is the “take-off” method. Its essence is that each subsequent sheet overlaps the previous one by one wave. As mentioned above, its main advantage is ease of installation. As for the disadvantages, firstly, it is the increased consumption of material. Secondly, there will be a not very smooth edge on the edge of the roof, which will spoil the whole look, so it needs to be trimmed.
The next way to lay slate on a roof is to, by filing adjacent corners, achieve complete alignment of the sheets with each other vertically. So, for example, if you lay slate from left to right, then trimming should begin at the junction of the second sheet of the bottom row and the first, located in the top row. This method will allow you to reduce the consumption of roofing material to a minimum, but you will have to work diligently, since the method requires much more labor than the first.
In order for a slate roof installed by yourself to serve you for a long time, you must take into account some points, and it does not matter which flooring method was chosen. First of all, you should use only special galvanized fasteners; their role may well be nails, self-tapping screws and self-tapping screws. At the same time, given the fragility of the material, it is better to have a pre-required diameter at the fastening site.
You can also moisten the cut line with water before sawing, this will make the process easier. And in order to avoid unwanted breakage of the sheet, you should not put too much pressure on the tool you will be cutting with.
The installation of a slate roof also requires the presence of sheathing. It must be quite reliable, so for its installation, wooden blocks with a cross-section of 60x60 mm are used, as well as special linings. The step should be no more than 75 cm, or rather, it should be such that there are at least three beams under each sheet. It is very important that the wood is well dried, otherwise during the natural decrease in its moisture content the mounting holes will expand.
In addition, the width of the overlap also depends on the terrain, namely, if the house is located somewhere in nature, and tall trees grow around it, then it is better to increase this parameter, both vertically and horizontally. And all because falling leaves can get under the roofing material, and this is fraught with its premature destruction. Also, all the debris that gets under the edges of the slate will swell, absorbing moisture, which will lead to the formation of unwanted cracks, the roof will begin to leak, and it will need urgent repairs.
In order for the roof to be sufficiently reliable, it is not enough to choose high-quality material; you should also pay attention to the question of how to properly cover the roof with slate with your own hands.
Basically, domestic material is used. The number of its waves can be from 6 to 8, and depending on this it has different thickness and width. The first parameter for six-wave sheets is 5, 6 and 7 mm, and the second is 1125 mm. The width of the eight- and seven-wave slate will be 1130 or 980 mm, while the thickness will be 5.8 mm. In addition, parameters such as wave pitch and the distance between the crest and the bottom may also be different.
You must pay attention to all this when making calculations and purchasing material. If roofing a roof with slate with your own hands is carried out using the “running start” method, then the wider the wave, the greater the consumption will be due to the increase in the overlap area. You also need to pay enough attention to the quality of the slate; defects are not allowed on the sheets. The slightest chips, cracks and other imperfections should be a reason to replace defective copies.
Having chosen the “running start” method, it would be more appropriate to use an eight-wave sheet. How to cover a roof with slate in this case it will result in significant savings in material. The sheets must be cut in half using a grinder or a hacksaw. The number of such halves should correspond to the number of odd rows, since they will begin them. Each even row should be assembled from whole products. We fasten the half in the first row, and then there are whole sheets with an overlap in one wave. The next row (second) consists entirely of whole slate. Thanks to this technology, the junction of the sheets of the previous row will overlap the middle of the sheet located in the next line.
The question of how to lay slate on the roof without displacement is also relevant, even taking into account the fact that this technology is more labor-intensive. It consists in . So, for example, when laying from left to right, you need to file the lower corners of the sheets in the top row by 130 mm along the wavelength and by 100 mm in its width. After fitting, each sheet is fixed with appropriate fasteners; do not forget about the special gasket for the head. And to make the house pleasing to the eye, you can paint the slate in any color, thereby adding originality and uniqueness to your building.
The industry produces several types of slate:
asbestos: inexpensive, fairly durable and heat-resistant material; to increase impact resistance, the asbestos fibers in it are bonded with cement;
Asbestos slate
Plastic slate
Sheathing is a structure made of wooden beams attached perpendicular to the rafters. It must be strong enough to support the weight of the roof.
Slate lathing
Marking and fastening the sheathing
Installation of sheathing near the chimney
Installation of this material does not require special skills or knowledge. However, since slate sheets have significant weight, and lifting them onto the roof is quite problematic, at least 3 people must take part in the work.
When laying, take into account the direction of the prevailing winds
There are two main ways to lay this material:
with offset (“staggered”): used when the slope is narrow vertically and wide horizontally, the first sheet is cut into 4 waves (6-wave into three); each subsequent sheet is placed on the last wave of the previous one;
Slate laying methods
Laying without displacement (with cut corners)
Joining sheets at one point is unacceptable
1. Before laying slate, you should prepare: drill holes in it for fasteners with a diameter a couple of millimeters larger than the thickness of the nail.
The slate is secured with special nails using backing plates
How to cover a roof with slate yourself
Laying slate on a roof is not particularly difficult if you first familiarize yourself with the work technology and prepare the necessary tools and fasteners.
Despite the emergence of new roofing materials, the popularity of traditional asbestos-cement slate remains quite high. This is explained by the affordable cost of the material, the ability to install the roofing with your own hands, without the use of specialized tools. Classic slate is suitable for simple single-pitched and double-pitched roofs; it can be used to cover a hipped or hipped roof.
Slate is highly resistant to static loads, resistant to aggressive environments, and is easy to process. The disadvantages include the rather large weight of the material - when installing it yourself, you need to attract one or two assistants to lift the slate sheets onto the roof without the risk of damaging them.
When considering the question of how to cover a roof with slate, it should be noted that this material is best used for laying on roofs with simple geometry. It is best if the roof has a slope of up to 20° or more than 35°, since in this case the likelihood of snow accumulation in winter is reduced.
The technology for laying covering on a pitched roof involves the installation of slate sheets that comply with GOST 30340-95. It could be slate:
The length of any type of slate sheet is 1750 mm.
When choosing slate, you need to pay attention to its markings, which indicate the height and pitch of the wave. The arrangement of sheets of material on the roof should be developed taking into account these parameters. The wider the wave pitch, the larger the area of material spent on vertical overlap. Selecting slate and the method of laying it is based on the size and configuration of the roof slopes.
When determining how to cover a roof with slate, you need to take into account the drainage system. If the gutter for collecting precipitation is supposed to be located under the roof overhang, it is enough to lay the outermost row with an overhang of 200-250 mm relative to the wall of the building. If water from the roof will drain directly onto the ground, the overhang should be at least 400 mm.
Slate rafter system
Before you install the roofing yourself, you should make sure that the rafter system is suitable for laying slate. This material belongs to the heavy category, so the roof frame design must be designed for high loads, which include:
If the roof is designed for metal tiles, ondulin or other lightweight materials, it may be necessary to reduce the installation pitch of the rafter legs or use struts to increase the rigidity of the wooden trusses. Particular attention should be paid to the roof frame if slate is intended to be used to cover an old soft roof.
The minimum cross-section of rafters for a slate roof is 50×180 mm, the sheathing is made of 60×60 mm bars or unedged boards 15-25 mm thick. The pitch of the board sheathing should be 200 - 1000 mm. When using sheathing made of bars, it should be taken into account that each sheet must be supported by at least three horizontal jumpers. A 60×120 m beam or a 60×150 mm board is mounted in the ridge part.
To properly lay slate, the sheathing must be made of dry lumber that does not have deformations.
If you plan to install a chimney or exhaust pipe on the roof, you need to make a special sheathing for the structures before laying the roofing. The arrangement of the drainage system should be completed before laying the roofing. On the bottom row of the sheathing it is necessary to fill a strip of metal about 300 mm wide and 2-3 mm thick, which will prevent the destruction of the lower edge of the roof under load. The metal strip should be waterproofed on both sides, and holes should be made for roofing fasteners.
If you are going to install a slate covering with your own hands for the first time, you should know that this material allows you to attach no more than two layers at one point. Thus, the installation scheme should be well thought out at the roof design stage.
The sheets must be mounted with a horizontal overlap in one or two waves. A single wave overlap is most often used if it is necessary to cover a fairly steep slope with a small snow load. An overlap of two waves is required for flat slopes; this design is much more reliable, but the total cost of the coating with such installation increases, especially with a large wave pitch. Vertically, the top sheet must overlap the bottom sheet by at least 200 mm.
The installation technology requires starting installation from one of the lower corners of the slope and continuing along the eaves overhang. The slate should be laid taking into account the wind rose: the overlap should be located on the leeward side. It is recommended to lay the first row of sheets along a pre-tensioned rope so that the overhang is neat and even. To avoid combining more than two layers of slate at one point, various installation options are used. The most popular methods are staggered installation (with offset) and without offset.
The staggered installation is popular due to its simplicity. In this case, the new row is laid with an offset relative to the bottom one. Thanks to this, it is possible to avoid the overlap of waves and no more than two sheets of slate are joined at any point. When installing with offset, it is necessary to trim the outer sheets and trim the top edge of the last row on the roof slope.
Staggered laying is ideal for installing eight-wave slate - just offset in four waves and use halves of cut sheets to start each odd row. The offset lines in this installation option are arranged aesthetically, in a checkerboard pattern.
If you lay slate without displacement, you can save roofing material, but this is a more labor-intensive option, which should be taken into account when starting installation yourself. In this case, it is necessary to trim the corners to the width of the wave and 120-140 mm in height. To lay the covering elements from left to right, the lower corner of each sheet of the top row is trimmed from the side covering the previous slate sheet of the horizontal row.
The question of how to cover a roof with slate is directly related to the choice of fasteners and the method of their installation. Slate nails, self-tapping screws and self-tapping screws are characterized by an enlarged head and are installed using a special rubber gasket, which ensures the tightness of the fastening point. The fasteners should not be driven in or screwed in all the way.
To avoid damage to slate sheets during installation, it is recommended to mark and drill holes in them for fasteners in advance. The holes should have a diameter 2-3 mm larger than the diameter of the nail or screw.
The slate is attached to the roof only at the crest of the wave. The first attachment point is located in the lower part in the second (overlapping) wave with a distance of 120-150 mm from the edge. The second attachment point is diagonally from the first, and the attachment at the top in the second wave is carried out after laying the overlapping slate roofing sheet.
After installing the covering with your own hands, you should install special ridge elements made of asbestos cement, arrange all abutments and joints, ensuring reliable waterproofing.
Safety rules and maintaining the integrity of slate
When working on the roof, not only installation technology must be observed, but also safety precautions. It is necessary to use safety cables and ropes. If the height of the building exceeds 6 meters, fencing should be provided. To carefully lift the slate sheet, it is recommended to use a nylon cable and a pulley system. If you need to cover a low building, assistants can supply the material.
Walk on the installed surface carefully. In order to freely walk on a slate roof during its repair or maintenance, it is necessary to install wooden ladders to distribute the load.
Compliance with safety precautions implies the use of protective equipment when working with asbestos-cement material: when drilling and cutting slate sheets, use a respirator correctly to protect the respiratory tract from harmful dust.
Laying slate on the roof, how to cover it correctly, installation of slate roofing
Are you asking yourself how to cover and cover the entire roof with slate correctly? Installing slate on a roof does not present any difficulties if you first familiarize yourself with all the work technology and prepare the necessary tools and fasteners. In this article you will learn in detail about laying slate with your own hands and its advantages.
Many new roofing materials have appeared on the modern market, but the popularity of conventional asbestos-cement slate remains unchanged. This can be explained by the affordable cost of this material, the ability to install the roofing yourself, without the use of specialized construction tools. Classic slate is suitable for simple pitched roofs; it can be used to cover hip or hip roofs.
Having considered the question of how to cover a roof with slate, we note that such material is best used for installation on roofs with simple geometry.
The coating installation technology involves the correct laying of slate on the roof in accordance with GOST 30340-95. The slate can be of the following type:
When choosing the type of slate, you need to know its marking, where its height and wave pitch will be indicated. The final arrangement of sheets of this material on the roof should be drawn up taking into account these parameters. With a wide wave pitch, a large area of building material will be lost to the vertical overlap. It is worth choosing slate and the method of its installation, focusing on its size and the configuration of all roof slopes. 
When determining how to cover the roof with slate, you need to take into account the drainage system. When placing a rain gutter under the roof overhang, you need to lay the outermost row with an overhang of 250 mm from the wall of the building. When water flows from the roof to the ground, the overhang must be at least 400 mm.
Before installing the roofing yourself, you need to make sure that the rafter-type system will be suitable for laying slate. Such material can be classified as heavy, and the structure of the pitched roof frame is designed for high loads, for example, such as:
When designing a roof for metal tiles or other lightweight materials, you may need to reduce the pitch of the rafters or use struts to increase the reliability of wooden trusses.
For a slate roof, the minimum cross-section of the rafters will be 50×180 mm, the sheathing is installed from 60×60 mm bars.
The sheathing pitch is 1000 mm.
When using sheathing made of bars, you need to take into account that each slate sheet must have a certain support of at least three lintels.
A beam of 60×120 m is installed in the ridge part.
For more correct laying of slate, the lathing is made from dry special lumber without any deformation.
If a chimney or exhaust pipe is installed on the roof, then special sheathing will be required before laying the final roof covering. The installation of the drainage system is carried out before laying the roofing. On the very bottom row of the sheathing you need to fill a strip of metal, which will prevent the destruction of the lower edge of the roof under external loads. The metal strip must be waterproofed on both sides, and holes must be made for roof fasteners.
Slate roof covering
The sheets must be installed with a certain overlap along the horizontal plane in one or two waves. When overlapping in one wave, they cover a fairly steep slope with a slight external snow load. An overlap of two waves is suitable for flatter slopes; this design is much more reliable, but the final cost of the coating for this installation also increases, this is especially noticeable with a wider wave pitch. The top sheet is vertically overlapped with the bottom sheet by at least 200 mm.
The installation technology requires starting installation from the corner of the lower slope and continuing along the entire eaves edge. The slate must be laid taking into account the wind rose: and the overlap of the sheets must be located on the leeward side. The first row of sheets must be laid along a pre-tensioned special rope so that the overhang is very neat and even. To avoid combining several layers of slate at one point, different types of laying are used. The more common methods are installation with and without offset.
Offset installation is popular due to its simplicity. In this case, the next row is laid with an offset relative to the first. Thanks to this method, it is possible to avoid a certain overlap of wave overlaps and no more than two sheets of slate are joined at any different point.
When installing offset, trim the outer slate sheets and trim the upper edge of the outer row on the roof slope.
Offset installation is ideal for installing eight-wave slate. With this method, it will be enough to make an offset of four waves and use halves of cut slate sheets to start each odd row. And all the offset lines in this installation option will be located very nicely and evenly in a checkerboard pattern.
If you install slate without displacement, you save roofing material, but this is the most labor-intensive method, which should be taken into account when starting installation and installation yourself. In this case, you will need to trim the corners by one wave width and 140 mm in height. To lay the covering pieces from left to right, you need to trim the bottom corner of each slate sheet in the top row on the side that will cover the previous sheet in the horizontal row.
Laying slate with offset
Slate roofing is directly related to the choice of fasteners and the method of installation. Slate nails, self-tapping screws and various screws are characterized by a wider head and are mounted using a specific rubber gasket, which ensures sufficient tightness of the fastening point. It is important to remember that the fasteners are not driven in or screwed in all the way.
It is necessary to lay slate on the roof only at the crest of the wave. The first point of attachment is considered to be the lower part of the overlapped wave with a certain distance from the edge. The second fastening point is considered to be a point diagonally from the first, and its fastening at the top in the second wave is carried out after installing the overlying slate roofing sheet.
After installing the covering yourself, you need to lay special ridge parts made of asbestos cement, install all junctions and joints, and ensure reliable and high-quality waterproofing.
If you want to paint the slate, we will strip and coat it with a silicone primer before painting the slate. Then you can coat it; waterproof paint based on silicone or acrylic is suitable for this purpose, which is what we recommend.
Safety rules when working with slate sheets
When working on the roof, you need to follow not only installation technologies, but also safety precautions. It is necessary to use safety cables and special ropes. If the height of the house is higher than 6 meters, it is necessary to provide appropriate fencing. To carefully lift slate sheets, you need to use a special nylon cable and a block system. In low-rise buildings, the material is supplied by assistants.
You need to walk on the installed surface very carefully. In order to move freely on a slate roof during its repair or maintenance, you need to install wooden ladders to distribute the load more evenly.
Compliance with all safety precautions implies the use of protective equipment when working with asbestos-cement building material: when drilling or cutting sheets, use a respirator correctly to protect your respiratory tract from harmful slate dust.
Do-it-yourself slate roofing for a private house
Like any construction process, slate roofing requires advance planning. First of all, it is worth deciding on the shape of the future coating, since all further calculations depend on it. Roofs made of sheet materials can be flat (single-pitched with a slope of 1-2%), single-pitched and gable roofless (with a slope
7%) and attic – where the slope of the slope(s) is 40 percent or more.
It is not recommended to choose intermediate options, since, for example, with slopes in the range of 20-35 °, the maximum amount of snow accumulates on the roof in winter. Also sometimes roofs with four slopes or complex configurations are installed, but, as a rule, the simplest geometry of all possible is chosen for slate.
As a rule, domestic slate is used in construction, and its dimensions are regulated by GOST 30340-95: six-wave with a sheet thickness of 6, 5 or 7 mm, width 1125 mm, seven- and eight-wave with a thickness of 5.8 mm, width - 980 and 1130 mm, respectively . The length of any type of sheet is set to 1750 mm.
From the mark, you can determine, in addition to the number of waves, the height of the wave (the distance between the bottom and the crest) and its pitch - the distance between identical points of adjacent waves. For example, brand 40/150-8 designates 8-wave slate with a wave height of 40 mm and a pitch of 150 mm. These parameters should not be underestimated when calculating. With the same width, when laying staggered (with overlapping waves of vertical sheets) the consumption of six-wave slate will be greater than that of eight-wave slate- after all, the step of each wave is wider, and accordingly, the area that will be spent on overlap increases.
The order in which the roof is laid is also influenced by the selected sedimentation water collection system. You can install a gutter under the overhang of the last row of slate - then it will be enough for the sheets of this row to protrude beyond the line of the building facade by 200-250mm. If you plan to directly discharge water directly from the roof onto the local area, the size of the projection should be 400-500 mm.
Before laying slate on the roof, rafters are arranged in accordance with the selected roof structure and slope angle. Then the sheathing is laid along the rafters. As a rule, 50x180 timber is used for rafters and installed in such a way that the narrow side is vertical.
The sheathing made of unedged boards 15-25 mm, or timber 60x60, is installed perpendicular to the rafters. In this case, the distance between the boards is taken to be 200-1250 mm, and between the bars - so that each sheet rests on at least three of them (
400-450 mm). If there is a pipe on the roof, it is necessary to properly frame it around it (see illustration).
When installing a gutter, it is installed before installing the sheets. Under the sheets of the latter, to the lower edge of the roof of the row, a strip of metal 2-3 mm thick and 250-300 mm wide is placed on the sheathing to prevent chipping of the edges of the sheets. Waterproofing is applied to the strip on both sides. It is also necessary to pre-drill holes in the metal in the places where the slate will be attached. To improve the performance of the existing (attic) roof, a vapor barrier membrane can also be laid under the slate.
Horizontally adjacent sheets are always overlapped. The overlap can be one or two waves. The second option is more expensive, but provides higher roof strength. The vertical overlap should not be less than 200 mm. In general, there are several installation methods. Since it is problematic to fix more than two layers of slate at one point, this problem has to be solved, and there are different ways.
The most popular - staggered styling. With it, each new row is laid with a shift relative to the previous one, due to which the wave overlaps in each of the rows do not coincide, and only two sheets can be joined at any point. To perform shifts, you have to cut off several waves from the outermost sheet. However, this method in the last vertical rows gives an uneven edge of the roof, and it has to be specially trimmed.
For eight-wave slate, there is a more practical version of the same method. All the first sheets of odd (every other) horizontal rows are cut in half (into 4 waves). As a result, the offset lines will be quite clearly repeated across the row, which is quite convenient and aesthetically pleasing. In addition, the sawn halves of the sheet are enough to start two rows at once. After the first sheets (including halves) are installed, you no longer have to worry about the offset, but simply lay the sheets horizontally - the offset is formed naturally. Trimming may only be necessary to straighten the end edge.
There is a more economical (in terms of material consumption), but labor-intensive method - installation without displacement. In this case, if the sheets are laid from left to right, then it is necessary to trim the corners of the sheets of the top row by approximately 100 mm along the width of the wave and by 120-140 mm along its length. The lower corner is trimmed from the side that covers the previous sheet of its horizontal row. Due to this, normal overlap of all sheets is achieved, both horizontally and vertically (all this is illustrated in the figure).
When laying slate on a roof special screws, self-tapping screws or nails are used. All types of fasteners have an enlarged cap and a rubber gasket under it. It is strongly recommended to mark the sheets in advance according to the pitch of the sheathing and drill holes in them for fasteners. In the case of screws and self-tapping screws, this is generally the only way, but careless driving of a nail can split the sheet.
The location of the holes is as follows: in the lower corner of the sheet, in the second overlapped wave, and symmetrically - diagonally (through the upper overlap sheet). The last sheet of the horizontal row is also additionally attached to the sixth (penultimate) wave. All types of fasteners are installed in the wave crest. Any other placement of nails and screws will cause the material to deteriorate quickly. 120-150 mm depart from the transverse edge of the sheet (depending on the amount of vertical overlap between the rows).
If it is necessary to move on slate, do this carefully, avoiding impacts and sudden pressure. For subsequent cleaning of the roof and similar work, wooden scaffolds with transverse strips-steps are placed on top of the slate in the right places. When the building height is 6 m or more, a fence made of metal reinforcement is installed around the roof. During work, safety ropes and other devices are used.
For the installation of ridges, roof joints, cornices, junctions with pipes, etc. areas there are special figured elements made of asbestos cement. Their installation, especially in the case of reinforcement with concrete and bitumen mastic, provides sufficient reliability. Sometimes I use galvanized strips and even wooden boards. However, this is not very aesthetically pleasing, and these structures will last much less. A properly constructed slate roof can last without repair (except for emergencies caused by external influences) for at least 50 years.
Laying slate on the roof - cutting it correctly with your own hands
Do-it-yourself slate laying is a fairly simple, albeit responsible undertaking that even a beginner in construction work can do.
In order for a roof made of slate to serve as expected (more than 50 years), you should approach roofing work armed with theoretical knowledge in advance.
The article discusses the technology of the process and provides brief instructions that will tell you how to properly cover a roof with slate.
Slate roofs are always popular in the construction of summer houses, cottages, country houses, garages and other buildings.
This is a fairly inexpensive material: one square meter of roofing, taking into account waterproofing and fastening systems, will cost you about 250 - 300 rubles when laying slate yourself.
If you resort to the services of professional installers, the cost of the roof will increase slightly, but will still remain quite acceptable.
The service life of slate with proper installation is more than 50 years. At the same time, the material reliably protects the room from moisture penetration, is not afraid of precipitation and sunlight, and is fire resistant.
The size and thickness of slate sheets are regulated by GOSTs: a standard sheet of 6 - 8 waves should be 1.75 m in length.
The width varies from 5.8 mm to 7.5 mm depending on the type of sheet. Asbestos cement, the main material for the production of slate, is gray or light gray in color.
To give the material a different color, a special technology using pigments is used, so you can easily choose an option that will harmoniously fit into the architecture of the building.
A pitched roof may have a smaller angle of inclination, but before covering the roof with slate, you should install a denser sheathing and a reliable waterproofing layer.
Sheets on flatter roofs will have to be laid with a strong overlap, up to 30 cm.
Before you start laying slate yourself, you need to calculate how many sheets you will need for construction work.
You need to accurately measure the dimensions of the roof using a tape measure or use drawings if the roof has not yet been erected.
It is worth buying materials with a small reserve so that at the last moment you do not have to go to the store for additional materials and arrange delivery.
The length of the roof is measured along the eaves overhang, then divided by the width of one sheet.
10% is added to the resulting figure - this is the margin for laying slate sheets overlapping. Round the resulting figure - this is how many full sheets are needed for one horizontal row.
Then measure the length of the roof from the edge of the eaves to the ridge, add 15 - 20% and round again.
Divide the resulting figure by the length of one sheet - this way you will find out how many horizontal rows will be needed to completely cover the roof.
The product of the two results obtained is the total number of sheets that will be required.
When choosing slate in a store, carefully check the integrity of each sheet, as this is a fragile material that easily chips and cracks.
Be sure to make sure that the material is well packaged for transportation: several layers of paper are laid between the sheets so that they are not damaged during transportation.
Before ordering slate from a store, prepare a place to store it: choose a large, flat space and cover it with waterproof film.
Slate is very heavy (the weight of one sheet can reach 30 - 35 kg), so it must be stored in an easily accessible place where it will be convenient for workers to approach.
Before you start laying slate, you need to prepare a reliable rafter system.
Since slate is heavier than most modern materials, the rafter system must be very strong and withstand heavy physical loads.
The lathing will serve as a good base for installation.
Before covering the roof with slate with your own hands, pay attention to several important details:
Installing sheathing near a chimney requires compliance with fire safety regulations. The minimum distance from the pipe to the beams is 13 cm.
To lay slate yourself, you first need to prepare, sort and cut the sheets. For cutting you will need a hacksaw, grinder or jigsaw.
Slate is cut on special wooden walkways so that the cutting line is raised above the ground. The cutting line is marked using a long ruler or straight edge.
If you are going to cut slate yourself using a jigsaw or hacksaw, then moisten the cutting line generously with water - this will soften the material, prevent overheating, and settle asbestos dust.
During the cutting process, constantly water both the slate itself and the tool with water.
You can cut slate using sharpened nails or a drill.
Holes with a diameter of 5 mm are made along the cutting line in increments of approximately half a centimeter.
Then the material must be placed on a table or other reliable support and carefully split.
Asbestos dust can cause serious harm to health, so cutting slate requires wearing a special respiratory mask, generously moistened with water.
Now let's talk about how to lay slate correctly yourself, without involving specialists.
Laying slate on the roof begins with planning the work. Pay attention to the direction of the wind: start laying the material from the leeward side - this way, even in a strong wind or thunderstorm, the roof will not leak at the joints.
To lay the rows evenly, stretch a rope or cord along the cornice.
There are two types of slate roofing: staggered (horizontal rows are slightly offset relative to each other so that the joints do not coincide) or without offset (at the intersection of the seams, the corners of each sheet are slightly trimmed).
Proper installation of slate is the key to the durability and reliability of the roof. Read the instructions to the end before laying the slate, pay attention to how to nail the slate correctly.
Before covering the roof with slate, cut all the sheets needed for the job. The sheets are laid with a slight overlap to ensure more reliable waterproofing, in horizontal rows.
The main task: to shift each subsequent row relative to the previous one so that the joints do not coincide. This is exactly how to lay slate with your own hands.
The first row can be laid out from solid sheets so that they slightly overlap each other. The horizontal rows should slightly cover each other.
Fastening is carried out using special nails or self-tapping screws, and be sure to place a soft gasket, for example, made of rubber, under the head.
The first sheet of the second horizontal row needs to be cut slightly lengthwise, by one or two waves, so that the joints of the second row are shifted and do not coincide with the joints of the first. Then, starting from the second, you can lay whole sheets.
Just like the sheets themselves, the horizontal rows should overlap each other slightly. With a slope slope of 20 degrees, slate can be laid with an overlap of 14–17 cm; with a gentler slope, it is necessary to increase the overlap to 20–22 cm to ensure reliable waterproofing.
The first sheet of the third row is cut even further to provide further offset relative to the second row, and so on - each laid row should be slightly offset.
So, if you cut the first sheet of the second row into one wave, then in the third row you will have to cut two or three waves, in the fourth - three or four, etc.
To avoid large wastage of material, use an offset of half the width of the sheet, alternating the arrangement of whole sheets and half sheets in even and odd rows.
Installation of slate should be carried out carefully. Before nailing the slate, make holes of a slightly larger diameter, do not drive the nails in tightly.
A small gap will compensate for various climate changes and roof shifts.
When the temperature changes, the volume of the slate changes, so if you hammer the nails in too tightly, the material may crack or split.
To properly lay slate without displacement, you must first prepare the sheets.
With this installation method, a corner is cut off from the sheets, which overlaps with the already laid sheet.
Laying begins from the right or left lower edge of the roof - a solid sheet is laid first.
If you started work on the right side, then you need to cut off the upper right corner of all other sheets of the first row. If you started laying on the left side, then the upper left corner is cut off.
Sheets for the second and all subsequent rows except the last must be prepared in advance by cutting off the corners at all intersection points.
Since the first sheet of each row only touches the other sheets on one edge, you only need to trim the bottom corner, right or left, depending on which side you started working on.
For the last sheet, you only need to cut off the upper corner on the corresponding side.
For the remaining sheets in the row, the upper and lower corners are cut off at the intersections with the adjacent row. Lastly, another solid sheet is laid.
Now you know how to properly cover a roof with slate with your own hands, how to lay it and how to attach slate to the roof.
Do-it-yourself slate roofing is reliable and inexpensive, and it’s always a pleasure to invest your labor in creating warmth and comfort in your home.
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.
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 for better protection from rain, before laying the slate, you need to lay a waterproofing carpet made of ordinary roofing felt or other waterproofing 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, the weight of slate with a reinforced profile or, for example, six-wave slate, is different, therefore the sheathing should be of different sections.
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 it is not possible to buy an edged board. 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 standard size asbestos cement sheets, 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 is made when laying roofing felt or other insulating material. The roof ridge is also covered with roofing felt.
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 is large 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 horizontal slope of the roof is small 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. It must be remembered that the drilled holes must be 2-3 mm larger than the diameter of the 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 less than 20°, slate is laid on the roof 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 or 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; there should be a small gap between the sheet and the wooden element. 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.
Slate is a popular roofing material. Slate sheets come in both flat and wavy profiles - they are more popular because they provide better drainage of water from roofs and have greater strength. The service life of slate directly depends on proper installation.
DIY slate installation
To perform the sheathing, you need a square block of 60 mm. It is attached to the rafters in increments of about 50 cm. For the sheathing you need well-dried wood, otherwise when it dries the block will decrease in size and the fastening of the slate will weaken. Extensions of the sheathing beyond the edge of the roof must be calculated in such a way as to avoid cutting the slate sheets - cut edges do not look aesthetically pleasing.
Preparing the roof sheathing
Slate is laid in two ways: staggered or with corners trimmed. Laying slate staggered is less labor-intensive. For this installation method, it is better to buy eight-wave slate, since it is laid with a shift of half a sheet, and there will be a lot of unused trimmings from the seven-wave slate. The installation method with cutting corners requires more time, since each sheet of slate has to be trimmed.
Laying the slate begins from the bottom edge of the slope on the windiest side. The first sheet must be leveled using a plumb line, since it will be difficult to correct the distortion. Each subsequent row is overlapped, its size depends on the angle of inclination of the slope. For a roof with a slope of 20-45 degrees, an overlap of 10 cm is sufficient.
Attach the slate to the sheathing using galvanized slate roofing nails, driving them into the crest of the wave.
1 – sheathing block; 2 – slate; 3 – nail; 4 – washer; 5 – rubber gasket.
You should not drive the nail too deeply - this can create overstress in the material, and at the first load or temperature change it will crack. The nails are driven until they lightly touch the slate head and in no case are bent from the attic side - this can also cause the sheets to split. It is better to drill holes for fasteners with a drill with a drill diameter 1-2 mm larger than the diameter of the nails.
Technology of laying slate staggered
In general, the technology is similar to staggered laying, but the sheets are laid in even rows without shifting, and to eliminate double overlap and large gaps, the corners of the sheets are cut end to end in accordance with the diagram.
Laying slate with cutting corners
This technology is more labor-intensive, but the finished roof covering is smoother, the gaps are smaller, and the service life of the roof is longer.
With this installation and maintaining the gaps, all cut corners are covered with top sheets, and the roof reliably protects the structure from precipitation and melt water.
To protect against lichens, slate roofing can be coated with an antiseptic. You can also paint it with slate paint if desired. Thus, you will receive a reliable, durable and, at the same time, inexpensive roofing covering.
Slate is a classic material for arranging roofs for various purposes with a slope of 12 to 30 degrees ( according to GOST). Even now, with the advent of many other modern materials, slate roofs are very relevant. And all because slate, along with its disadvantages, has undeniable advantages over more modern materials.
Before buying slate for roofing, You need to learn more about all the pros and cons this material. If everything suits you, you can start choosing slate.
Today on the building materials market you can find slate of various sizes, qualities and colors. The most common and classically used: six-wave, seven-wave and eight-wave. Also slate varies in thickness. Depending on these parameters, the consumption per 1 square meter of roofing and, of course, the cost will differ.
In this article you will learn how to cover a roof with slate with your own hands and how to calculate the amount of slate for the roof.
Before laying the actual slate on the roof, it is necessary to complete all work related to the installation of rafters and sheathing, insulation, steam and waterproofing. There can be two options: the attic space is used as a living space, or not.
Warm roof roof pie
Both classic roofing felt and modern materials of your choice can be used as insulation, for example, Izospan A. The material is laid perpendicular to the rafters, starting from the lower edge of the roof slope. In this case, the top layer should overlap the bottom layer by 15-20 cm.
Attached using a construction stapler. It should be slightly stretched, and the distance from below to the insulation should be at least 20 mm.
On top of the insulating material, parallel to the ridge, directly into the counter-batten, the longitudinal lathing is stuffed. Its step must be carried out in such a way that one sheet of slate is attached to at least three points. In practice, they take a step of at least 45 cm, that is, one solid sheet, 175 cm long, is laid on 4 boards.
Slate lathing is made from boards 20-25 mm thick and 150 – 170 mm wide or from bars 50*50 mm.
It is allowed to use lathing from unplaned wood, the most important thing here is that it is even, of the same thickness along the entire length, without traces of rotting and not too wide (so that it does not lead to damage during use). Sheets of slate are already attached directly to the sheathing.
Cold Roof Pie
In places where the slope plane is adjacent to a vertical wall or chimney, it is necessary to make a continuous sheathing with a margin of 50 cm in all directions.
When choosing a slate profile from which the roof will be made, it is worth considering that, The more waves a product sheet has, the more economical the roofing will be. This means that adjacent sheets will overlap less, hence more sheet area will be beneficial.
NOTE!
It should be remembered that When calculating the amount of slate required, you need to take into account the angle of the roof.
Let's consider two options.
Roof overlap
Accordingly, in the first case, if the roof is flat, more material will be needed. In addition, at small slope angles, snow may accumulate on the roof in winter, which will lead to significant loads on the roof structure.
To calculate the number of slate sheets, as well as calculation of rafters and sheathing, we recommend using our
online calculator
Before installing slate directly on the roof, 
it is necessary to prepare individual elements so that you do not have to do this at a height where it is not entirely convenient.
Preparation consists of drilling holes for fasteners, trimming corners, if we will lay it in this way, and cutting sheets in the case when the height of the roof does not include a whole number of elements.
First you need to measure with a tape measure the distance between the middles of the rafters to which the element will be attached. Not forgetting to take into account the slope above the cornice.
Then we mark the same distance on slate sheets through the wave, and make holes in the marked places using a drill or screwdriver and a metal drill. The hole should be a couple of millimeters larger than the diameter of the fastener used.
Holes for fasteners that will hold the elements in those places where they overlap one another, it is better to drill directly on the roof using a screwdriver. Otherwise, there is a risk of not getting the fasteners into both sheets at once during installation.
CAREFULLY!
All work related to slate cutting and drilling must be carried out wearing protective gloves, a mask and a respirator. Asbestos particles contained in dust are very dangerous if ingested.
If there is a need to cut slate sheets due to their large length, then we do this immediately, in preparation for installation. This will make the sheet lighter and more convenient to cut.
Slate cutting tools
When everything is ready, you can begin installing the slate.
To lift the prepared sheets onto the roof, you need to use two or three long bars or strong boards and lifting ropes to avoid damage to the sheets. When working at height, you must use safety ropes. You cannot walk on slate in ordinary shoes; you need to use wooden boards or soft shoes.
Lifting cover
Typically, slate sheets are laid on the roof from right to left, from bottom to top. But, if there are strong winds in a given area, then you can lay them from left to right, the main thing is that the overlap is on the leeward side.
How to properly nail slate to a roof:
Fastening the slate sheet
The first bottom row of slate is laid along a special rope, which is stretched at the required distance from the cornice.
NOTE!
During installation, you need to be careful so that more than two sheets do not overlap in one place, otherwise the material will begin to crack in this place.
Laying 8 wave slate is possible in several ways, but there are only two main ones: the method with shifting the sheets (staggered), and the method with cutting off the corners.
The most common due to its mediocrity. The bottom line is that the slate sheets in the next row are shifted relative to the previous row by several waves. This method avoids the coincidence of wave overlaps, and there will be no more than two connections at the same time in one place. So, how to correctly lay slate according to the instructions for shifting sheets:
How to cover a roof with slate correctly
Trimming corners
After laying the entire roof it is necessary to build a ridge element. It is made from roofing iron in such a way that so that it covers 200-250 mm of the top row of slate. After installation and alignment, it is nailed to the sheathing through the top edge of the sheets through one wave.
Roofing elements such as valleys, valleys, roof junctions with vertical walls and chimneys are also made of roofing iron and nailed with an overlap of 25-30 cm on top of the slate sheets. You can also purchase ready-made roofing elements; they will look better.
After the slate roof construction work is completed, it is recommended to visually inspect all joints for gaps. Gaps larger than 5 mm should be sealed with sealant or mastic.
Slate ridge
To increase the service life of a slate roof, you can paint it any color with a special paint, or treat it with an antibacterial solution.
Installation of slate sheet in the video below:
Slate is a popular material that is inexpensive, but highly reliable and durable. If you paint it, then in terms of decorativeness it can easily compete with modern roofing innovations. Therefore, the scope of application of slate is almost unlimited: asbestos-cement roofs can be found on both modest country houses and luxury cottages.
The spread of the material is also facilitated by the fact that laying slate on a roof is not a difficult job, anyone can do it. But in order for the coating to last, as it should, for at least half a century, you will need to study all the nuances of this simple but important event.
Many people believe that slate is a universal roofing material. This is wrong. To prevent precipitation from seeping under the slate, it is recommended to lay it only on single- or gable roofs with a slope of at least 15°. If you want to use a flatter roof as a base, you will have to construct serious waterproofing under the sheathing from several layers of roofing felt or membrane, and also increase the overlap of adjacent sheets up to 300 mm.
Slate laying methods
To obtain a roofing covering, slate is fixed to the sheathing in horizontal rows, moving from bottom to top (from the eaves). Each subsequent sheet in a row is placed on the previous one by 1-2 waves. Each subsequent row is also shifted to the previous one, as a rule, by 120-200 mm.
There are two ways to lay out slate:
As a rule, wave slate is laid staggered. This option is less labor intensive as it does not involve a lot of pruning. Installing slate without offset is much more difficult, since almost every sheet has to be cut in the corners. But this technology also has a significant advantage - it saves material.
Let's take a step-by-step look at the process of covering a roof with slate, focusing on the difference in the two layout schemes.
Slate laying technology Stage #1. Sheathing device
The first step to attaching the slate is to prepare the base - the sheathing, which is fixed directly to the rafters. The lathing can be continuous or sparse.
Solid sheathing is a flooring made of OSB, plywood or boards. Such a base is usually used if it is necessary to cover the roof with slate with an unusually small thickness.
For standard slate with a thickness in accordance with GOST, a sparse sheathing is recommended - a structure made of bars installed at a certain pitch on top of the rafters. A suitable cross-section of the lathing is 40-70 mm. Too thin bars are not used, due to their possible damage under external load (for example, under the influence of fallen snow). Too thick bars are also bad. When warped, they can cause rupture of asbestos-cement fibers and the formation of cracks in slate.
It is recommended to use bars of different heights as part of the sheathing frame. Ordinary bars usually have a cross-section of 60x60 mm; they are fixed in odd rows. Even rows are made up of elements whose height is slightly higher - half the thickness of the slate used. For example, if the thickness of the slate is 6 mm, then the height of the “even” bars is 63 mm. The first (cornice) bar also has a different height - 66 mm, which should rise above the ordinary ones by the thickness of the slate sheet. For uniformity, a different scheme is often used: they use slats of the same height - 60x60 mm, but, in even rows and near the eaves, they are built up using linings 3 mm thick.
The sheathing is fixed to the rafters at right angles using nails or self-tapping screws. Since slate is a durable, non-bending material, 3 support bars are sufficient to install each sheet. The pitch of the batten lathing depends on the length of the sheet. The standard length is 1750 mm, respectively, the lathing pitch is 700-750 mm.
1-2 sheathing beams are installed on the ridge (on each slope) for subsequent fastening of the ridge parts to them. The height of the bars is selected on the spot, in fact.
Additionally, lathing is done around the chimney. To do this, ordinary bars are fixed along the perimeter of the pipe trunk at a distance of at least 130 mm from it (to ensure fire safety).
Stage #2. Calculation of the amount of slate
Correctly calculating the amount of slate is another important step, which will save the roofer from the need to purchase 1-2 missing sheets at the last moment and order transport for this.
You need to understand that not the entire surface of the material is used to directly cover the roof. Part of the area (along the perimeter of the sheet) is lost under the overlap.
Therefore, the calculation of the amount of slate is carried out as follows:
1. Determine the amount of slate in the transverse (horizontal) row (P) using the formula:
P = (L + 2C) / (B2 – B1),
2. Determine the amount of slate in the longitudinal row (n) using the formula:
n = (Lo + C1) / (L2 – L1),
3. The resulting figures are rounded up to a whole number, multiplied and the total number of sheets per 1 roof slope is obtained. If the roof is gable, then the calculated number of sheets (+10% - for damage and defects) is purchased in double quantity.
Stage #3. Cutting slate sheets
Before lifting slate sheets onto the roof, it is necessary to sort them and, in accordance with the chosen laying pattern, cut them.
You can cut slate with several tools:
The easiest and fastest way to cut slate is with a grinder with a stone (concrete) disc or a diamond disc.
Cutting process:
Sheets are cut in the same way with a hacksaw or jigsaw, but when using these tools you need to be extremely careful not to break them.
Cutting methods using a drill or slate nail deserve special attention.
When using a drill, use a 2 mm drill to make through holes along the cutting line in increments of 0.5 cm. After drilling is completed, one edge of the sheet is placed on a support (a table, for example), and pressure is applied to the other edge, after which the slate is split along the intended line.
Instead of a drill bit, you can use a sharpened nail and a hammer to make through holes. To do this, place the nail on the intended line and hit the head with a hammer. The blows should be careful, strong enough, but not sharp. In this way, multiple pinholes are punched at a short distance from each other. After this, the sheet is split into two parts.
The technology for cutting slate sheets with a grinder is shown in the video:
Stage #4. Laying slate sheets
Laying the slate begins on the side opposite to the direction of the prevailing winds. That is, the installation of sheets begins on the left side if strong winds blow from the right, and vice versa. This will prevent rain and snow from blowing into areas where the sheets overlap.
A cord is pulled along the cornice at a distance of the length of the overhang in order to level the rows of slate along it. Instead of a cord, you can use a flat wooden strip.
Sequence of work in a staggered layout:
1. The first horizontal row begins to be made up of whole sheets of slate. Each subsequent sheet overlaps 1-2 waves of the previous one (as a rule, there is 1 wave per overlap). Fastening is carried out using roofing nails or self-tapping screws with soft (rubber) gaskets.
2. In the second row, the first sheet is cut into a certain number of waves, depending on the desired offset amount. Then whole, uncut products are placed. The sheets overlap the underlying row, forming an overlap of 200 mm - with a slope slope of 15-20°, 150 mm - with a slope of more than 20°. That is, the greater the slope, the less permissible overlap.
3. The third and all subsequent rows begin with sheets cut into twice the number of waves cut off from the first sheet of the underlying row. For example, if the first sheet of the second row was shortened by 1 wave, then the first sheet of the third row will have to be cut by 2 waves, then by 3 waves, etc. It is more convenient to offset by 1/2 the width of the slate. In this case, you will only have to cut the sheets in half in each even row. Odd rows are made up of whole sheets.
4. The ridge row is laid last, making it up from sheets cut across.
In a layout without offset:
1. The first sheet is laid whole, uncut. Align it along the cord, secure it with nails or self-tapping screws. For subsequent sheets of the first row, the upper right corner is beveled at an angle (if installation begins on the right side of the slope).
2. The lower left corner of the first sheet of the second row is cut off, after which it is joined to the cut corner of the second sheet in the first row. Subsequent sheets are beveled in two corners - in the upper right and lower left (located diagonally). For the last sheet of the second row (located on the left), only the upper right corner is cut off.
3. The elements of the top row (under the ridge) are cut according to the lower left corner and according to the height - in fact. The corners of the last sheet are not cut off. Such a scheme for forming corners is reliable only when laying sheets from right to left. If the installation direction goes from left to right, then trimming is performed in opposite corners (instead of left corners - right corners and vice versa).
Stage #5. Installation of additional elements
After covering the roof with slate, the final stage begins - installation of additional elements. To cover the ridge, it is advisable to use special ridge parts made of asbestos cement. Each such element consists of two parts connected on hinges. As an alternative to the factory part, you can use a galvanized sheet, bent on a sheet bending machine or by hand.
Collars of chimneys, dormer windows and places where they abut walls are made using corner parts made of asbestos cement or galvanized collars. They are fixed on top of slate sheets using self-tapping screws passed through the crests of the waves. The upper edge of the apron is attached to the wall and sealed. The lower edge overlaps at least 1 wave of the row sheet.
The valleys are covered with galvanized or asbestos-cement trays, installing them from bottom to top. In this case, the longitudinal walls of the tray must be overlapped with slate sheets by at least 150 mm.
Once the installation of the additional elements has been completed, the installation of the slate roof can be considered complete.
Features of fastening slate on the roof
An important nuance that should be discussed separately is the selection of fasteners and their use in the process of fastening slate to the roof.
The following can be used as fastening elements:
Fasteners are mounted in two ways (to choose from):
An important feature of fastening: during installation, the nail or self-tapping screw is not pulled to the limit to the slate sheet, but a small gap of 2-3 mm is left - to compensate for temperature expansion. If you neglect this advice, the slate roof will soon begin to crack.
Fasteners are installed only in the upward protruding parts of the wave (in the crest), where the slate comes into contact with the sheathing (to connect the roofing sheet to the sheathing material). Fastening is carried out at a distance of 80-100 mm from the edges of the sheets.
Since the slate usually rests on 3 sheathing bars, and fastening is done at the points of contact of the 2 waves with the sheathing, the total number of nails (screws) for each sheet is 6 pieces.
Some additional nuances of how to cover a roof with slate can be learned from the video:
Conclusions - is it really possible to do everything yourself?
The technology for installing a slate roof is very simple. It will not require you to spend much time, labor or money. Despite this, the roof will turn out beautiful (especially if you get acquainted with slate paint!), reliable and durable.
