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 withstand an adult. Durability is also inherent in it: slate does not undergo combustion, it is absolutely not susceptible 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 there are more and more various options for the roof. Let's consider in more detail step by step instructions how to cover the roof with slate so that you don’t remember 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 the 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 later was not confirmed, on the human body, manufacturers began to produce slate with chrysotile-asbestos filler.
The bulk of manufacturers are located in Russia, Ukraine and Belarus.
Advantages of using asbestos slate:
- low price;
- increased strength is achieved by reinforcing and a certain form of the sheet;
- ease of use and installation;
- excellent sound absorption;
- low thermal conductivity in relation to other roofing materials;
- absolute incombustibility of the coating.
Disadvantages of using slate:
- very brittle material with point impacts;
- the ability to absorb and retain moisture from the air;
- the likelihood of cracking in the heat;
- very heavy weight when compared with a metal profile;
- from exposure to ultraviolet and wind, the strength of the coating decreases over time;
- growth of lichen and moss on outer surface slate.
How to lift the slate on the roof manually?
On large construction sites of high-rise buildings, a variety of construction machines and fixtures are available. Therefore, such questions do not even arise there. And the slate on the roof is immediately raised in large piles.
But in the construction of a private house, the use of a crane is extremely costly and not cost-effective. Therefore, builders have adapted to lift the slate with a mechanized single or double block, or a mechanical winch. But the winch is handy for a large number sheets, because it has a low speed.
If you need to lift a single sheet, whether using a pulley or not, be sure to tie the slings correctly to distribute the weight more evenly. Fiber for ropes is best used from natural fibers.
First, two corners from the bottom are tied, 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 raised to the roof.
If the height of the walls is small, you can use the ladder, as if on rails, to lift the sheet up.
Correct calculation of slate on the roof
For different types of roofs, a different calculation of the necessary raw materials is used. Consider the main ways:
shed roof
This is a very practical type of coating, since it requires much less slate and workers. And installation is quick and easy. Such a roof has a slope of 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 come off the roof itself without requiring your intervention.
On average, the slope angle is from 10 to 50. In Russia, it is recommended, by building codes, to build a roof with a slope of 20-30, 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 is calculated from edge to edge on the other side. Effective - the width of the coating 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 are needed per 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 \u200b\u200bthe roof itself, but questions often arise about fasteners. For example, how many nails are needed per sheet of asbestos slate. Let's figure it out.
Rule of thumb: A solid sheet of roofing material requires an average of 4 specific nails. More is possible, less is absolutely impossible!
Each nail is an additional hole in the roof, which can lead to leakage of precipitation. Let's say for a roof, with an angle of inclination of 45-90 degrees, the optimal number of nails is 6-8 pieces.
Slate installation. Stages of work
The first and basic rule of laying the roof is to carry out work only from the bottom up. The rest can be selected for each roof individually. For example, the side from which to start laying the roof. The priority will be the one from where the wind blows more often in the area.
There are two main ways of laying roofing materials:
- slate fastening with offset;
- fastening of slate with cut corners.
And already from the shape of the roof will depend on how the fastening will be made. For example, for a roof with a wide slope along the horizontal line and narrow along the vertical line, the first option is best suited. A roof with a wide slope in a vertical line is more convenient to lay in the second way. It is imperative to ensure a flat cut line of the roof during installation, 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 place of work.
- Installation - installation of rafters and the construction of a crate for slate with laying materials for insulation on it.
- The final stage is fixing the slate on the crate with profiled nails. Most main stage, the duration of the service life and the quality of operation of the roof depend on it.
Overlapping when laying sheets
If before buying required amount material for roofing works, you studied in detail the principles of its installation, you should have already traced the main stages.
- Development of a detailed layout of sheets on the crate. It is produced at the stage of procurement of materials. This way you avoid buying extra sheets.
- Bringing the shape of the sheets to the required one with the help of a grinder. It should be moistened in advance to prevent crumbling of the material. Checking the sheets for the absence of marriage.
- Laying slate sheets. Work starts from below. Attach the slate in one of the upper corners to the crate, be sure to end up with the roof. And then fix another, three nails in the crest of the wave, at different angles.
- Each subsequent sheet of slate along the horizontal line is fixed in the same way, overlapping in 1-2 waves.
- Go through the entire row along the perimeter in this way, hammering four nails.
- The next row begins with an overlap on the first at least in half, continuing like this with each corner.
- So we pass the entire slope of the roof, do not forget to leave an opening for ventilation. Then the same is repeated on the other side. In the end, the roof will resemble a checkerboard pattern.
Laying slate with cutting corners
This method requires the application of large forces. But the result is worth it, because the roof laid in a similar way, looks perfectly even, without unnecessary gaps, which extends its service life at times. 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 of the beginning of laying the roofing material. In fact, it does not matter, to whom it is convenient.
- Fitting slate sheets for laying. 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 row are never cut off on each slope.
- processing sheets of the lower first row are cut according to the direction.
The second row is stacked in accordance with this order:
- 1st sheet is the corner from the bottom left;
- sheets in the middle will go lower from the left and upper right;
- extreme sheet - top right.
The last row is the same, but the edge profile is not cut to get a complete picture of a flat roof.
How and with what to fix the slate on the roof? Fixing options
The most reliable fixation of the slate sheet is made with a nail, it does not allow the sheet to deform and leaves it immobile. There is one caveat in fastening with nails: for reliable fastening and preventing leaks, the nail must be drawn 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 deep into the crate. Usually nails are selected with a length of 7 to 12 cm. A feature of the roof nails is the increased head width up to 14mm. Also, the nail head is made of galvanized steel to avoid corrosion. Although the roofing nails made from galvanized steel are considered the best.
There are two types of roofing nails:
- smooth;
- ruffed.
When choosing the former, it is imperative 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 there are special notches on the nail that securely fix the fasteners in the crate. The only disadvantage of these nails is that they are very difficult to dismantle in the future.
On the roofing nail, there is always an elastic gasket that is not exposed to external factors. The shape of the washer completely repeats the bend of the slate sheet, which ensures complete sealing of the coating.
Roof fastening is allowed by ordinary construction hammer, but in this way it is possible to spoil the slate sheet, leaving the smallest cracks on it, which in the future will affect the service life not for the better.
It is better to use a drill with a diameter of 2 mm larger than the fastener for these purposes. When hammering, hold the nail with pliers so as not to damage the slate sheet with an accidental blow. The impact force must also be calculated so as not to deform the wave of the sheet with a nail gasket.
The use of self-tapping screws in fastening a slate sheet
It is possible to fix slate sheets on the crate without the use of nails, using self-tapping screws. This method has its advantages:
- increased strength due to hardening of the metal of self-tapping screws;
- a huge selection of self-tapping screws in the length and shape of the cap;
- wide color range of self-tapping screws;
- self-tapping screws are supplemented with a special sealant, reliably sealing the roof surface.
During fastening with self-tapping screws, you will also need to make a hole with a drill. A self-tapping screw is driven into the hole with a screwdriver. This significantly reduces the time of covering the roof.
Installation of the ridge and wind bar
No less attention should be paid to both the ridge and the wind bar, since the most great pressure, ridge guarantees the tightness of the ends of the slate on top of the roofs. The end reduces pressure on the slate sheets on the sides, for which it got its name.
Mounting the skate, the main nuances:
- before fixing the ridge, it is imperative to complete the ventilation space under the roof;
- in order to avoid snow drift under the ridge, all even slopes are closed with special strips;
- the beginning of work should be carried out from the planks outside the end plank with an allowance of 20-30 cm;
- be sure to overlap on each side at least 10 cm;
- to facilitate work, bars of the right size are fixed under the workpiece.
Mounting the end plate:
- the end bar is fixed to the level along the first wave of the entire row, while blocking the corner;
- attach it with self-tapping screws, from the side, from above and on the ridges;
- dock them on a whip of 10 cm;
- all joints of the plank are sealed with a silicone compound specially designed for roofing.
When fixing the end plate, make sure that it covers the end of the wave so that precipitation does not leak inside.
Installation of snow retainers
The basic principles of fastening all types of snow retainers:
- to fix this device, it is necessary to strengthen the crate.
- fix snow retainers flush with the lower slope of the roof;
- the minimum distance to the roof cut from the snow retainer is not less than 400 mm;
Although the traditional asbestos-cement slate cannot be attributed to innovative materials, it is being replaced by more modern coatings, and in many European countries it was completely abandoned, on Russian market it does not lose its former popularity, as it is quite durable and reliable. In this regard, the question of how correct styling do-it-yourself wave slate , still interested in homeowners. Moreover, this material may well be transformed by painting in the chosen color, which will be in harmony with the color of the facade. Therefore, slate can be used not only to cover 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 of the nuances of this process must be taken into account. First of all, it must be said that slate is not such a versatile material as many people think, since it is mainly suitable for covering one and two pitched roofs having a slope of at least 15 degrees. If it is planned to lay this coating on a more gentle slope, under the coating it will be necessary to equip the crate according to special rules, reliable membrane or roofing felt waterproofing, and also increase the mutual overlap of the sheets.
Varieties of slate and its dimensions
Slate was originally called roofing material, made from cement mortar and asbestos fibers, which act as a reinforcing component that gives the sheets durability and strength.
Since the wave version of the sheets has a higher mechanical strength, rigidity, and is more resistant to external influences, this form was taken as the basis for manufacturing roofing sheets from other materials, such as keramoplast, cellulose fibers impregnated with bitumen, Various types polymers and sheet metal. Therefore, these materials also began to be called, while mentioning 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 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.
- Seven-wave sheets have dimensions of 1750 × 980 mm, a thickness of 5.8 mm and a weight of 23.2 kg. The step and wave height are already smaller - 150 and 40 mm
- The eight-wave version is a sheet with a size of 1750 × 1130 mm, a thickness of 5.2 ÷ 5.8 mm, and a weight of 23 ÷ 26 kg. The step and height of the wave are the same as those of the seven-wave. It is this type of slate that is most often used in housing construction.
Infrequently, but still, sheets of a more “modest” format are also used - 1200 long, 680 mm wide, with the same 40 mm wave as that of eight-wave slate, and weighing only 9 kg.
The technical documentation may contain letter designations wave slate parameters. To understand this, you should pay attention to the diagram below, where: B - width; L is the length of the sheet; S is the distance between wave crests; t is the thickness of the slate; h is the height of an ordinary wave; h1 and h2 are the height of the overlying 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 to its installation, you should have an idea about its positive qualities and existing shortcomings.
- The advantages of asbestos-cement slate include:
- relatively affordable cost of the material;
- sufficiently high strength, due to the reinforcement and the characteristic shape of the sheets;
— simplicity of processing and carrying out roofing works;
- good sound absorption;
- low thermal conductivity - the roof will not heat up in the sun as much as it is covered, for example, with metal corrugated board or metal tiles;
- incombustibility of the material.
- The disadvantages of such a slate can be called the following properties:
— brittleness under point and shock loading;
- hygroscopicity of the material - it can be saturated with moisture;
- the possibility of a break with sudden changes in temperature;
- quite a lot of weight compared to other types roofing, 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 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, therefore, in European countries, it was decided to ban products containing asbestos.
In fairness, it should be noted that the carcinogenic properties of this roofing 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 mosses, 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 well worth a look.
Ondulin
Ondulin, which is otherwise called bituminous slate or euroslate, began to be produced in Europe when the technology for reinforcing bitumen with cellulose fibers appeared, which fasten, stiffen and prevent cracking of the coating during temperature changes.
Despite the fact that slate is not as popular as, for example, metal tiles, it has good technical performance. Apart from good quality this material is cost effective compared to many other roof coverings. Therefore, it is worth familiarizing yourself with the 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 form and composition.
Form slate varies depending on the number of waves. This affects the width and length of the sheets. You can more clearly see the varieties in the form in the table.
| Name | Number of waves, pcs. | Wave step, mm | Wave height, mm | Sheet length, mm | Sheet width, mm | Sheet thickness, mm | Weight of the 1st 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 |
Such varieties 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 slate sheets will be required with a wide wave pitch (for example, for a six-wave). In this case, with a vertical overlap, you will need to spend more material.
By composition slate can be cement-fiber or asbestos-cement. The first and second options are suitable for laying 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.
Preparing for styling
When the required type of slate is selected, you can begin preparatory work. They include:
- Dismantling of the old coating.
- Site preparation for work.
- Material preparation.
First of all, you need to do dismantling of the old coating. It is necessary to choose a period when the weather will be dry, without rain. It is better to remove the old slate with an assistant. The sequence of dismantling the material should be opposite to its laying.
Then a free area is allocated where it will be held material preparation. The platform must be level so that it is convenient to cut and measure sheets.
Preparation material consists in the processing of 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 faster from the roof.
Laying methods
After preparing the main material, it is necessary 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 stacked with a shift relative to each other. This method is good in that you can prevent more than 2 sheets of slate from joining at the 1st point.
Necessary tools and materials
To install the slate, you must purchase the following tools and materials:
- Thermal insulation.
- Waterproofing (polypropylene film).
- Rafter.
- Construction tape.
- Wooden bars for the crate (60x60 mm).
- Antiseptic.
- Nails are galvanized.
- 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, it must be taken 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 to be installed is 3, then a total of 18 sheets will be needed. It is always necessary to purchase material with a margin, given that it will be cut off or may break off during installation.
For fastening slate, it is best to use self-tapping screws. To calculate their length, it is necessary to take the thickness of the crate, add the thickness of the slate and the height of its wave.
After preparing everything necessary, the slate is laid.
Laying technology
The technology for laying slate consists of several stages:
- Installation of thermal insulation.
- Waterproofing installations.
- Lathing installation.
- Slate laying.
Installation of thermal insulation can be skipped if it is not necessary. But those who want to insulate the upper 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 overlapped.
Lay the waterproofing film with the fleecy side inward. Due to this, a moisture barrier is created and the liquid will not penetrate into the thermal insulation.
To fix the waterproofing, you will need construction stapler who need to install it on the roof. If necessary, you can perform a 2-layer waterproofing, which will increase additional protection from moisture.
The next step is the installation of the crate. For this, apply wooden bars, which must be treated with an antiseptic. It is forbidden to use wet material, otherwise, after drying, it will decrease in size and deform.
To install the crate, you must perform the following steps:
- Perform the calculation of the crate (depending on the size of the slate).
- Install vertical bars on the slopes.
- Install horizontal on vertical.
- 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 bars 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 crate, the installation of slate on the roof begins.
Slate laying. Step-by-step instruction
Pre-measured and cut sheets of slate, as mentioned above, are treated with a water-repellent compound. Slate should be prepared in advance by marking it. Holes are marked and drilled.
Holes for fastening the slate to the crate are made larger diameter than the diameter of the screw.
The fastening of the slate to the crate is carried out in order. In order to determine from which side to start laying, it is necessary to determine the direction of the wind and install it against its direction. Due to this, the wind will not blow into the cracks, which will not lead to tearing them 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 just such a fastener.
When attaching the first bottom row, follow the instructions:
- Attach the first sheet.
- Lay the second over the first one. Overlap to do in 1 wave. But to increase the strength, the overlap can be done in 2 waves.
- On the second impose the third and subsequent sheets.
All sheets should be fixed to the crate. If you pre-drill the holes, the installation will be much easier. When tightening self-tapping screws, it is necessary to adhere to the following rule: you cannot tighten it tightly, otherwise, after a change in temperature, a slight slip of the slate occurs and its further cracking. In this case, you can not leave a large gap, because in the future the mount can unwind. The ideal solution there will be a gap between the cap and the sheet - 2 mm.
Fixings should be done 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 start installing the second row. The first sheet of the second row must be shortened by 2 times and fixed on the crate. 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 so that the edges remain even.
In order to cover the roof as efficiently as possible, it is recommended to follow the following tips from professionals:
- When choosing sheet parameters, adhere to GOST 30340-95.
- Use a quality timber for the crate.
- Be sure to waterproof.
- In the absence of experience in covering the roof, it is best to use the simplest method of installing slate - with a shift, which was described above.
- When making fasteners, you can not nail the slate strongly, otherwise it will crack over time.
- When working at height, you need to use insurance (use safety ropes).
Before starting work, be sure to necessary calculations, pick up quality material, otherwise the work on overlapping the roof will be in vain. After installing the slate, you need to monitor its condition: clean it from dirt, snow, and ice in time. Proper care increases its service life.
This video will help you learn how to properly lay the slate on the roof of the house. All stages of installation are presented.
Laying slate on the roof does not take much time if you follow all the steps step by step. Due modern technologies transparent and colored options are created, which makes it possible to make the roof of the house not only strong and durable, but also transform it from an aesthetic point of view.
Despite the fact that a lot of new roofing has now appeared, asbestos-cement slate is not going to give up its positions yet. Many do not know how to properly lay slate. Consider the methods and technology of laying slate with cutting corners with your own hands.
Types of slate
Before talking about the methods, let us briefly dwell on the types of this material. Currently, manufacturers produce corrugated and flat sheets of asbestos-cement slate. Each of them is intended for a certain type of work. As a rule, flat sheets are laid on the roof if its slope is at least 35 °. This is due to 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 mounted 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 slope of the roof is small, then for better protection from rain, before laying the slate, you need to lay a waterproofing carpet from ordinary roofing material or another hydro insulating material. The dimensions of asbestos-cement sheets also play an important role, since the step of the crate and the cross section of its elements depend on this. After all, with a reinforced profile or, for example, a six-wave one, it is different, therefore the crate should be of a different section.
Preparation for laying slate
Before laying the slate, it is necessary to prepare the base where it will be mounted. To do this, a crate of boards or bars is stuffed onto the exposed rafters. If a board is used, then its dimensions are usually 15–20 cm in width and 2–2.5 cm in thickness. Lumber can be used unedged, if possible to buy edged board No. The main thing is to sand the edges and impregnate with antiseptics and fire retardants to eliminate the risk of rotting and fire. If bars are used, then their cross section should be approximately 5 × 5 cm.
When buying lumber, you need to carefully inspect each board or bar and immediately reject the curves, with traces of a wood borer, with a lot of knots or bluish places (they indicate the beginning of decay). The wood must be dry, otherwise it will simply warp on the roof and the horizontality of the stacked slate sheets will be in question.
Before laying the slate, it is important to reinforce the roof overhangs and the ridge with boards in two rows, with no gap between them. The lathing bars are placed along the ridge perpendicular to the rafters with such a pitch that the slate sheet is supported and fastened at least three points along its length. For asbestos-cement sheets standard size the distance between the lathing bars or the center of the board should be approximately 55-60 cm. If a multiple number of sheets cannot be laid and trimming is required, then the length of the roof overhang can be reduced or increased.
After the installation of the crate, according to the rules for laying slate, it is necessary to make waterproofing with roofing material. 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 a value of 10-15 cm. The smaller the angle of the roof slope, the greater the overlap is done when laying roofing material or other insulating material. The roof ridge is also covered with roofing material.
Slate laying methods
It is possible to make a slate roof in two ways - with offset sheets, otherwise known as "spread out", or with cutting corners. The method of shifting slate sheets relative to each other is simpler and is most often used when installing roofing from asbestos-cement sheets. The disadvantage is the high consumption of material due to the fact that cutting along the length of the outer sheets is required.
In addition, it is necessary to observe the horizontal position of the laid material relative to the ridge and the lower overhang of the roof. Laying slates apart is recommended when the roof slope has big sizes horizontally and small vertically. In this case, the sheet is displaced by one wave, and there is no cornice overhang.
The second method is that the corners of each stacked sheet are trimmed. This is a more time-consuming 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 a joint of four adjacent sheets of slate does not form in one place. Do-it-yourself slate installation instructions indicate the correctness of trimming the corners. When laying roofing material from left to right, the left corner of the sheet is trimmed, when laying sheets from right to left, the right corner is cut off.
To properly lay slate, you need to know some of the nuances when working with this material. First of all, 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 larger than the diameter of the fixing nails or self-tapping screws by 2-3 mm. It is better not to cover the roof of a 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 with the fastening of sheets in the second wave from the edge. It is not recommended to pierce the slate with nails in order to prevent it from splitting at the attachment point. You need to drill holes with an electric drill or manually. Trimming corners is best done with an angle grinder, colloquially called a "grinder", or a hacksaw. When using a grinder, the cut is more even and does not crumble, and much less time is spent than when working with a hand tool.
Nails should be used special, with a metal washer, which will prevent water from entering the under-roof space at the attachment point. If self-tapping screws are used, then they must be with special thermal washers.
Now it is possible to make a roof from slate sheets of any color, and it is better to choose self-tapping screws to match the roofing material. At the joints of the sheets, it is recommended to lay a sealing hermetic cord or use a 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 facilitate the work. From which side to start laying will tell the prevailing direction of the winds in the area.
It is not recommended to fasten the slate sheets too tightly to the crate, between the sheet and wooden element there should be a small gap. But the number of nails per sheet is determined by the state of the wood of the rafter system, in particular, the crate. Wood that has served for a sufficient amount of time will require more nails or self-tapping screws. The fastening of the asbestos-cement sheet is carried out in the upper wave of the sheet. The use of self-tapping screws when installing the slate will make the mount 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 did not hear about a couple of decades ago. At a time when shops did not abound with such abundance, slate came to the aid of summer residents under construction. This available inexpensive material it is too early to “retire” because 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 slate a roof.
Slate is a sheet roofing material with a 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 various colors. In assortment construction stores you will meet 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 you cover the roof with slate, get acquainted with its advantages:
- Convenience and ease of installation with your own hands. Even a person without building experience can lay slate. It does not require special skills or expensive tools. Sheets can be cut using an ordinary hacksaw for metal or a grinder, and fixed on slate nails or self-tapping screws.
- Reliability. Do-it-yourself slate roofing is a reliable way to protect the attic from the penetration of moisture, cold and wind. This material is not afraid of hail, falling branches from nearby trees, because they will not harm it.
- Fire resistance. The refractory qualities of asbestos cement are another reason to use its roof coverings, because chimneys of heating appliances, fireplaces and stoves are brought to it. Roofing with slate is especially relevant for baths, the chimneys of which are heated to a temperature of 750-850 degrees.
- Long service life. If before covering the roof with slate, process truss system flame retardant and antiseptic, then the service life of the structure will reach 40-50 years.
- Affordable price. The average cost of 1 square. m of roofing with slate, 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, the costs will increase by 50%. But even with the labor costs of workers, this is half the price of metal tiles or ondulin.
Important! Slate has two special features that need to be treated with attention: with a lot of weight, it is a rather fragile material. Therefore, at the time of purchase, be sure to check the integrity of the sheet, make sure that there is a paper gasket between them. For the convenience of working on a construction site, a flat place for unloading and storage is prepared in advance by spreading a film there.
Requirements for the truss system
Before you cover the roof with slate, you should properly prepare the roof truss system. The fact is that this roofing material has a solid weight compared to modern counterparts. 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, observe the following 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 are considered, the humidity of which is not higher than 15-16%.
- For the manufacture of crates used bars of wood conifers size 6x6 cm, which will not break under the sheets.
- If you are nailing the sheathing with your own hands, make sure that each layer of slate rests on two or more bars.
- The distance from the edge of the sheet to the nearest bar of the crate should not be less than 150 mm.
Note! Of great importance is the angle of inclination of the roof slopes. Manufacturers recommend laying slate on the roof, the slope of which is 22 degrees or more. For single and gable roofs use slate, even if the angle is 5-15 degrees. However, the smaller the angle, the denser the crate should be. For the minimum permitted values, a solid base of moisture-resistant plywood is used.
Material Quantity Calculation
Before you cover the roof with slate, you should calculate how much material is needed. 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 over the eaves. If the roof is still only in the project, then take this value from the drawing. Divide the length of the eaves by the width of the slate sheet you will be using. By increasing this figure by 10% and rounding up to the nearest integer, you will get the number of sheets in one layout tier.
- Measure or find out from the project documentation the length of the roof from the ridge to the edge of the eaves. To calculate the required number of rows, this value is divided by the length of the sheet and 13% is added. The surcharge compensates for the overlap between the sheets.
- By multiplying the number of sheets in one row by the number of tiers, determine how much material is required to cover the slope. If the roof has two symmetrical slopes, the result is doubled.
Note! In case of damage to the sheet during do-it-yourself cutting or transportation, it is better to have a supply of material, 10% is enough. The asbestos dust generated during this is dangerous for the lungs, so you should only work in a respirator moistened with water.
Mounting principles
The junction of four corners, which is formed as a result, is the main difficulty of installation. To avoid breaking off pieces of material, deformation and penetration of water or wind into this vulnerable spot, there are two proven methods:
Important! Asbestos cement, from which most types of slate are produced, changes size with changes in humidity and temperature. Therefore, in order to prevent violation of the integrity of the sheet, holes of a larger diameter are drilled at the attachment points than the size of the self-tapping screw or nail. The fasteners are not screwed in until they stop, leaving a gap that compensates for fluctuations during heating.
Video instruction
