The construction market is flooded with roofing materials for every taste and wallet, about which we had not heard a couple of decades ago. At a time when shops did not abound in such abundance, slate came to the aid of summer cottages under construction. This affordable, inexpensive material is still too early to “retire,” since it is difficult to find an equivalent alternative among materials of the same price category. If you want to cut the cost of building a roof with your own hands in half, read in this article how to properly roof the roof with slate.
Slate is a sheet roofing material with a wavy or flat surface, which is made of asbestos cement by molding. Unpainted slate is a light gray tint, but manufacturers add pigments to it, dyeing in different colors. In the assortment of building stores you will find slate sheets consisting of 6-8 waves, according to the standard, the length of which is 1.75 m. GOST for this type of building product regulates the thickness of the material - it lies within 5.8-7.5 mm for different types of sheets . Before roofing slate, get acquainted with its advantages:
- Convenience and ease of installation by hand. Even a person without building experience can put slate. This does not require special skills or expensive tools. It is possible to cut sheets with the help of a usual metal saw or a grinder, and fix them on slate nails or self-tapping screws.
- Reliability. Do-it-yourself roofing slate is a reliable way to protect the attic from moisture, cold and wind. This material is not afraid of hail, falling branches from nearby trees, because they will not harm him.
- Fire resistance. Refractory qualities of asbestos cement are another reason to use its roof covers, because chimneys of heating appliances, fireplaces and stoves bring to it. Roofing slate is particularly relevant for baths, chimney pipes which are heated to a temperature of 750-850 degrees.
- Long service life. If, before covering the roof with slate, the truss system is treated with a fire retardant and an antiseptic, then the lifetime of the structure will reach 40-50 years.
- Affordable price. The average cost of 1 square. m roof slate, taking into account the price of fasteners and waterproofing is 200-250 rubles, if you do the work with your own hands. If you bring in a hired team of professional roofers to the process, the costs will increase by 50%. But even with the labor costs of workers, this is half the price than laying a flooring, metal tile 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, during the purchase be sure to check the integrity of the sheet, make sure that between them was a strip of paper. For the convenience of work on the construction site in advance prepare a flat place for unloading and storage, spread out the film there.
Roof system requirements
Before roofing slate, you should properly prepare the roof truss system. The fact is that this roofing material has a considerable weight in comparison with modern analogues. The weight of one sheet can reach 30-35 kg, and this is a serious load for the elements of the support frame. Creating a roof project, follow these rules:
- For the manufacture of truss legs, use boards 60x150 mm or thicker. The best option is considered to be the highest quality boards of 100x150 mm, the humidity of which is not higher than 15-16%.
- For the manufacture of sheathing use coniferous wood bars of size 6x6 cm, which will not break under the weight of slate sheets.
- If you are nailing the crate 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 cracking bar should not be less than 150 mm.
Note! Of great importance is the angle of inclination of the roof slopes. Manufacturers recommend laying the slate on the roof, the slope of which is 22 degrees or more. For shed and gable roofs use slate, even if the angle is 5-15 degrees. However, the smaller the angle, the tighter the crate should be. For the minimum allowed values apply a solid base of moisture-resistant plywood.
Calculation of the amount of material
Before covering the roof with slate, you should calculate how much material is required. To estimate the required number of sheets in order not to overpay for unnecessary balances, perform the calculations as follows:
- Take a tape measure and measure the length of the roof along the eaves overhang. If the roof is still only in the project, then take this value from the drawing. Divide the length of the overhang by the width of the slate sheet that you will use. Increasing this figure by 10% and rounded up to the whole in a big way, you get the number of sheets in one tier of the layout.
- 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, divide this value by the length of the sheet and add 13%. The surcharge compensates for the overlap between the sheets.
- Multiplying the number of sheets in one row by the number of tiers, it is determined how much material is required to cover the ramp. If the roof has two symmetrical slopes, the result is doubled.
Note! In case of damage to the sheet during the cutting with their own hands or transportation, it is better to have a supply of material, 10% is enough. Asbestos dust formed during the cutting of slate is dangerous for the lungs, so you should work only in a respirator moistened with water.
Principles of installation
The junction of the four corners, which is formed as a result of laying slate - the main difficulty of installation. To avoid chipping off pieces of material, deformation and penetration of water or wind into this vulnerable spot, there are two proven methods:
- Installation "in a break". To lay the sheets of the roof so the sheets of the second tier are cut into 1-2 waves, so that the joints between them do not coincide. To minimize the costs arising from cutting, this method is used only for wide but short skates. It is good if the work is done by hand, as it is almost impossible to make a mistake.
- Installation with undercut corners. To cut corners, make a template, the size of which is 103 mm horizontally, and 120-140 mm vertically. If the slate is laid in the classical way, starting from the lower right corner and moving to the left, then the first and last sheets do not require trimming of the corners. The remaining sheets are cut 1 or 2, depending on the location in the layout.
Important! Asbestos cement, from which most types of slate are produced, changes in size with changes in humidity and temperature. Therefore, in order to prevent damage to the integrity of the sheet, in the places of fastenings, holes are drilled with a larger diameter than the size of the screw or nail. Fasteners are not screwed all the way down, leaving a gap that compensates for vibrations when heated.