Despite the abundance of modern roofing materials available on the market, wave slate remains very popular, especially if property owners want to save their budget. The fact is that such roofing materials as metal, bitumen, plastic and others have one significant drawback — a high cost in terms of years of operation. For example, bitumen shingles will cost 2-3 times more than slate, but will last much less in terms of terms.
What is slate made of?
For the first time, the slate formula was patented in England, back in the early 19th century. So far, it has reached no changes:
- Portland Cement Of The M300 Brand…M500 (80-90%);
- Chrysotile-asbestos fiber (10-20%);
- Water (for making the mixture).
It turns out a plastic and very soft solution that fills special molds and is almost instantly dried to fix the wavy shape. The shape of the sheets can be any, but the most popular is wavy slate. This is due to the presence of additional stiffeners (waves) that can withstand the weight of snow, meltwater, wind gusts, hail, and other weather whims. Sheet slate is also produced by the industry, but it is almost never used as a roofing material, but is more often used for decorative purposes when working with facades and during the construction of fences.
The higher the grade of Portland cement, the stronger the slate will be, but because of its increased strength, it becomes very brittle. The classic formula provides for 4 parts of cement per 1 part of chrysotile asbestos. The binder is cement, and the reinforcing material is asbestos fiber. No other placeholders are provided in the shale.
Types of wave slate
Slate can be divided into the following groups::
- By the percentage of chrysotile asbestos, manufacturers indicate the composition of slate on packaging or product certificates;
- In size – 5,6,7, 8-wave slate with a width from 980 mm to 1130 mm.
- According to the thickness of the slate-5 and 7-wave slate is produced with a sheet thickness of 5.2 … 5.8 mm, 6 and 8-wave can be produced with a thickness from 6 mm to 7.5 mm.
Formally, slate producers can work according to the requirements of the state standard (30340 of 1995), or according to technical specifications, producing almost any series of slate that is not standardized according to GOST. There is also GOST 18124-95 for flat asbestos cement sheets.
Wave Slate Dimensions
Asbestos cement slate is a very strong, durable and practical material. It is extremely inexpensive compared to other roofing materials, the technology has been tested on millions of buildings around the world.
Operating experience has shown that for a wave slate, 50-60 years of operation, even in the most extreme conditions, is far from the limit of possibilities. On the streets of any CIS cities, you can find houses with roofs covered with slate 50, 60 and even 80 years ago.
One of the features of slate production technology is the size of the sheets. It is this profile shape, dimensions in length and width that ensure maximum strength of the material.:
- Five waves-1750 mm x 980 mm, thickness-5,8 mm;
- Six waves-1750 mm x 1125 mm, thickness-6-7. 5 mm;
- Seven waves – 1750 mm x 980 mm, thickness-5.2 or 5.8 mm;
- Eight waves-1750 mm x 1130 mm, thickness – 5.2 or 5.8 mm.
Slate sheets for 7 and 8 waves remain the most popular, while 5 and 6 waves are used situationally due to their increased cost. Also, 7, 8-wave slate has the most favorable ratio of nominal and useful area. In addition, the slate overlaps with neighboring sheets, and if you use 5 waves, a third of the area can be lost on ensuring the sealing of the roof. Sheets with a larger area are not produced, because material damage during installation increases significantly (large sheets cannot support their own weight if they are not properly transported). The height of an ordinary wave is usually 40 or 54 mm. The average sheet weight for 8 min min is 26 kg with a thickness of 5.8 mm.
Wave slate application area
Basically, wave slate is used as a roofing material. Over the years of using this material, many builders have significantly expanded the scope of application of wave slate:
- Construction of fences, fences, gates, gates;
- The use of slate as a fixed formwork material when pouring foundations and monolithic structures;
- For the construction of leaky tanks, warehouses, hangars, garages;
- As a finishing material or base for further finishing of facades;
- As a sheet material for drying or storing light bulk materials.
Many factories today produce wave slate abroad, producing products with certain characteristics (different colors, coated with their polymers, with a more complex formula for the solution for wave slate).
Advantages and disadvantages of wave shale
- Non-combustible material that does not support combustion (according to GOST 30244);
- The average service life as a roofing material is from 30 to 50-60 years;
- Does not require regular maintenance;
- It is not subject to destruction from corrosion, does not rot;
- Perfectly tolerates the direct action of UV radiation;
- With high thermal conductivity, creating an air cushion in the attic allows you to save on insulation.;
- Low weight, not requiring a powerful truss system;
- You can perform the installation yourself without using special equipment;
- High strength allows you to move around on the roof;
- Low heat under constant sunlight (unlike metal or tiles);
- The material is solid, does not change shape;
- Maintainability (damaged sheets can be replaced);
- Cutting slate is done with a regular hacksaw or grinder;
- The roof batten can be made of wood with a sufficiently large pitch;
- Does not conduct electric current;
- Under temperature fluctuations, it changes its geometry (thermal stability).
Low cost and a large number of advantages make wave slate a very popular roofing material until now. But there are also drawbacks:
- Fragility during installation;
- High weight compared to bitumen shingles, metal, roofing material;
- May be covered with moss;
- Water resistance is 24 hours, so it is not superfluous to apply additional layers of waterproofing on the roof.;
- It cannot withstand point loads or impacts;
- High requirements for the qualification of craftsmen and the quality of the grid;
- There is a wide variation in quality from different manufacturers.
Of course, the most advantageous advantage of wavy slate is the price. It varies on average from 178 rubles for 1 sheet of 8-wave slate.
The main disadvantage of slate at the moment is the content of asbestos fibers. They are dangerous to health, in the 90-ies in Europe, roofs using slate in residential buildings were banned, and later (2005), slate with asbestos fiber was generally banned throughout the European Union. This is due to the WHO report, in which asbestos was classified as the 1st group of carcinogens (the most dangerous), because they lead to cancer and exacerbation of diseases of the respiratory system.