Asbestos cement flat sheet, asbestos cement sheet (slate)

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Date: February 14, 2017

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Asbestos cement is a material that is used for rough and finishing finishing of premises, construction of economic facilities, etc. This building material is known to us as slate - we often see houses covered with slate sheets, slate fences, pavilions, etc.

The composition of asbestos cement includes the following components:

• Portland cement;
• water;
• quartz sand;
• asbestos;
• coloring matter.

They produce varieties of asbestos-cement sheets, which differ from each other, having different operational and technical characteristics.

Asbestos cement sheet, better known as slate, has not lost its glory as a unique building material for many decades.

What is slate?

Slate (“Schiefer” in German) is a roofing building material in the form of corrugated or flat sheets made from asbestos-cement mixture. The proportion of asbestos in it is 10–18 percent, the rest is Portland cement and water. In production, asbestos fibers are first fluffed and then mixed with other components. Next, a long sheet is formed from the resulting mixture, vacuumed and profiled, and then cut into sheets of the required dimensions and weight.

Flat and wave

In Russia, chrysolite asbestos is used to make slate. Imported roofing products can be produced using its analogue, amphibole asbestos. Both of these silicate minerals belong to the group of carcinogens.

But peridot fibers, after being bound with cement in a sheet of wave or flat material, are no longer a dangerous material. But amphibole, even after pressing and hardening in Portland cement mortar, remains a carcinogenic substance. No wonder it is gradually being banned around the world.

At Russian enterprises, it is manufactured for the most part according to GOSTs 30340-95 and 18124-95, which specify the standard sheet dimensions, number of waves and weight. According to the standards, its color should be gray. If asbestos-cement sheets have a different color, then they are painted or the pigment is added directly to the cement mixture. In the second case, the product is marked according to the factory specifications; GOST does not provide for the introduction of pigment additives.

Application area

1. When covering the frame of ventilation shafts.
2. For the manufacture of window lintels and window sills.
3. As a material for cubicle walls, partitions and even fences.
4. In production, it plays the role of flooring.
5. At power plants it is used as a sprinkler for cooling towers.
6. It is used to cover different types of buildings both outside and inside, including for covering ventilated facades and when assembling sandwich panels.
7. On private plots, it is used to cover any outbuildings, including toilets, enclosures, summer showers and gazebos.

Slate: its type, size and weight

There are four main types of asbestos-cement roofing sheets:

1. Flat
2. 6-wave
3. 7-wave
4. 8-wave

Flat products are used in the construction of partitions and roofs, while wave products are used exclusively for roofing material. Their production technology and composition are the same; they differ only in the cross-sectional profile.

Flat slate sheets

The GOST size of flat slate in millimeters is slabs 2500x1200, 3000x1200, 3000x1500, 3600x1200 and 3600x1500. Their typical thickness is 6, 8 and 10 mm. The weight of such asbestos-cement sheet ranges from 38 to 115 kg.

The wave material according to GOST is manufactured in two versions, indicating “40/150” or “54/200” in the markings. The first of the numbers in front of the scythe indicates the height of the waves in millimeters, and the second - their pitch. All such asbestos-cement sheets have a length of 1750 mm. This is the general standard. The size parameters differ only in the number of sizes, thickness and width.

The 6-wave version belongs to the second category “54/200” and is available with a thickness of 6 or 7.5 mm. Accordingly, the weight of this wavy sheet is 26 or 35 kg. And the width in both cases is 1125 mm.

Dimensions of 6-wave sheet

The 7-wave product has a “40/150” profile. Its thickness is 5.8 mm. The width of this asbestos-cement sheet is 980 mm. And the weight of slate with seven waves in cross-section is 23.2 kg.

The 8-wave sheet also falls into the “40/150” category. The size of this type of material in width and thickness is 1130x5.8 mm. The weight of a sheet of eight-wave asbestos cement product is 26.1 kg.

Sizes 7 and 8 wave sheet

In addition to the GOST format, slate is also produced according to factory specifications. Here the dimensions of the sheets are very different. Each enterprise now independently decides which product will be more competitive on the market.

The more precipitation falls on the roof, the thicker the wave slate should be purchased for it. When installing it yourself, it is easiest to work with the seven-wave elements of this roofing covering. These sheets are the smallest in size and have the least weight among analogues.

Knowing how much a particular brand weighs, you can easily calculate the total weight of the package to organize the transportation of this building material. A minimum of two workers are required to lift the material onto the roof. It is difficult to lift heavy sheets of corrugated or flat products alone and is not recommended. If you have to work alone, then it is better to look for another building material for roof cladding. The weight and size of the ondulin sheet in this case will be more handy.

Slate size chart

When calculating the amount of material in question required for a roof, you should focus not on its general dimensions in the markings, but on the working ones. Each sheet of wave sheet is superimposed on the previous one with an overlapping offset. Therefore, cutting and displacement will require about 15–20% of the area of ​​the roof to be covered.

The wave on one edge of the slate sheet is overlapping, and on the other - overlapping. The height of the first is always a few millimeters lower than the second, so that the roof sheathing lies flat during installation without distortion.

It is best to choose asbestos-cement roofing material that is unpainted and standard gray. Pigments added to the composition during production slightly reduce the strength characteristics of the product. It is more practical to then paint the already covered roof in the desired color.

Protective painting increases the service life and improves the overall appearance of the slate covering. The first layer of paint is applied to asbestos cement sheets before installation. Then, after the roof sheathing is completed, they are covered again.

Asbestos cement sheet - technical characteristics

Asbestos-cement boards have indicators that must be taken into account when using.

Main characteristics:

• strength of wave sheets - 18 MPa;
• flat - 23 MPa;
• weight of wave material - 1.6 g/cm3;
• flat - 1.8 g/cm3;
• viscosity of the pressed product - 2.5 kJ/m2;
• unpressed - 2.0 kJ/m2;
• freezing and thawing of pressed slabs - 50 cycles;
• unpressed - 25 cycles.

Plates and sheets are resistant to corrosion, are not afraid of rotting, and resist UV rays and chemicals. When products are coated with waterproof enamel, they become resistant to water. Water absorption is comparable to glazed ceramic tiles.

The use of asbestos-cement sheets for roofing buildings.

Advantages and disadvantages of wave slate

Among the advantages of asbestos cement material:

• Low heat transfer of roofing material;
• Non-flammability and good electrical insulation parameters;
• Possibility of painting in any color you like;
• Increased moisture resistance;
• Good sound insulation;
• No need for constant maintenance;
• Frost resistance and service life of 30–50 years.

On a sunny day, a metal tile roof will heat up much faster and stronger than an asbestos-cement roof. If holes appear in the latter, as part of the repair, it will be enough to replace only the damaged element. True, the size of the slate is such that the sheet will have to be changed completely. But due to its good strength characteristics, for installation it only needs a sheathing made of boards or bars with a pitch of 45–60 cm.

There are only four disadvantages:

• Heavy weight;
• Fragility to fracture;
• Low strength under strong point impacts;
• Susceptibility to moss growth.

The porosity of the material is conducive to moss germination

Transportation and installation of corrugated slate sheets should be carried out with the utmost care. And to solve problems with moss you will need a primer or paint.

Asbestos cement sheets are quite fragile

Blitz tips

1. All other things being equal, it is always recommended to use pressed sheets, except in conditions where savings are the main goal and everything else is unimportant.
2. The main condition for high-quality painting is not the choice of any special type of dye, but the fact that, regardless of its base, it should be intended specifically for coloring slate.
3. Having chosen it as a roofing covering, it is necessary to use reinforced rafters with boards with a thickness of 150 to 200 mm, installed at intervals of no more than a meter.

Decorative features of the material

To provide the consumer with a wide range of materials, with the possibility of selecting them to meet specific structural design requirements, flat slate is produced:

• unpainted;
• painted;
• invoiced.

Unpainted sheets are considered ordinary; they remain in the natural color of asbestos cement - gray. To obtain painted sheets, a primer layer is applied to the pressed slate, and then acrylic paint is applied. Mass dyeing is performed much less frequently. The color base is selected from the RAL, Monicolor, Tikkurila, NCS catalogues.

Textured slate is the most decorative option. There are several ways to decorate the surface of asbestos-cement sheets with texture:

• Creating a layer of stone chips of jasper, marble, serpentine, granites. A primer is applied to the surface of the slab, then an adhesive composition is applied, which is sprinkled with stone chips, followed by a varnish coating.
• Application of relief prints to the raw asbestos-cement mass using special stamps, after which the sheets are painted in the usual way. As a result, flat slate gets a new texture and color that imitates wood, stone, silk, etc.
• Creation of a textured polymer layer with marble or quartz filler.
• The use of iron oxide pigments as a filler, which gives the slate a “metallic” color (like titanium, bronze, aluminum, etc.).
• Coating sheets with colored cement plaster, which allows you to obtain an unusual texture and various shades with colored splashes.

Coatings with paint or stone chips not only increase the decorative properties of slate, but also play the role of a protective layer. Such sheets have increased wear resistance, wear less and last longer.

Due to their decorative component, they are used for finishing cladding of facades, installation of fencing for balconies (loggias), construction of fences and other visible surfaces of structures.

Sheathing device

The lathing for corrugated asbestos cement sheets should be sparse , the optimal distance between the boards is 50-70 centimeters , bars with a cross section of 50×50 mm are used to construct the structure.

The sheathing is laid on the rafter legs and attached to them with wood screws or ordinary nails.

The length of the fastening elements should be three times the thickness of the boards.

The highest quality structures are made from pine and larch. These wood species have low humidity. Before installation of the sheathing, the bars are treated with an antiseptic solution - this will prevent rotting and fungal attack.

Even and odd boards in the sheathing should be at different heights. Odd elements are installed higher than even ones by 4-6 mm. This allows you to avoid deformation of the slate sheets during their installation.

The sheathing is installed in the direction from the roof overhang to its ridge. To align elements extending beyond the overhangs, a stretched cord is used; along its line, the boards are cut to the excess length.

CAREFULLY!

In the areas of the ridge and valleys, the boards are laid closely even in sparse structures , which is associated with an increased load on the sheathing in these places.

After installing the main structure, the overhangs and gables are sheathed with clapboards, frontal boards are installed in the overhang areas, and gutters are installed.

The sheathing for flat slate must be continuous. For its construction, edged boards are used, laid with a solid carpet. Instead of edged boards, you can use sheets of plywood.

Installation of sheathing

Useful coverage area

The technology for installing slate on a roof is to lay it overlapping relative to each other. In this case, the overlap can be done in one or two waves. It is clear that this will reduce the area covered by the sheets.

In essence, it turns out that the usable area is the total area of ​​the sheet reduced by the overlap area. There is no need to count anything; there are tabular data that you can use. For example, for ordinary slate sheets, the usable area is:

• 7-wave – 1,336 m²;
• 8-wave – 1.57 m².

These indicators correspond to single-wave overlap. By the way, this is the technology most often used in construction.

Slate overlap in two waves Source krysha-expert.ru