Slate roofing has been popular for a long time. This article will tell you how to do a slate roof with your own hands, as well as what materials are used, and how to repair and paint a roof covered with slate.
Natural slate is a tile obtained by splitting layered rocks, primarily clay slate, which gave the name to this building material (schiefer in German means “slate”).
Like clay tiles, natural natural slate has been used in construction since ancient times. In the Middle Ages, roof tiles made from slate were widely used in the construction of buildings: you can still find many medieval buildings with slate roofs.
Modern materials for slate roofing
Currently, slate roofing involves the use of not expensive slate as a coating, but asbestos cement building materials, the most common of which are corrugated sheets.
It should be noted that there are a number of roofing materials made in the form of corrugated sheets, which also became known as slate. These are materials such as slate without the inclusion of asbestos, euroslate - corrugated sheets based on bitumen, metal slate and others.
Asbestos-cement slate, however, remains the most commonly used material for roofing, and it will be discussed in this article.
It is not without reason that the phrase “slate roof device” is associated primarily with asbestos cement slate, which is distinguished by its low price and a fairly easy installation procedure.
In addition, it has a number of other advantages, such as:
- low thermal conductivity;
- good resistance to frost;
- high resistance to negative environmental influences;
- fire safety;
- high service life of a slate roof;
- ease of repair.
Important: asbestos cement slate is quite cheap - several times cheaper than materials such as ceramic and metal tiles.
For the production of asbestos-cement sheets, a mixture consisting of fibrous asbestos, cement and water is used, which subsequently hardens.
Fine asbestos fibers evenly distributed in the cement act as a reinforcing mesh, which can significantly increase the tensile strength of the material and its impact strength.
There are several varieties of asbestos cement roofing slate:
- Slate is wavy with an ordinary profile, designated as "VO", the sheets of which are produced in the form of regular rectangles. In addition to standard sheets, special shapes are also produced to cover various roofing elements, such as the intersection points of the roof with chimney and ventilation pipes, dormers and other projections of the roof structure.
- Wavy slate with a reinforced profile ("VU"), designed to cover the roofs of industrial buildings and structures.
- Unified wavy slate ("UV"), which has recently become more widespread due to its dimensions, which are smaller than the size of VU slate, but larger than the size of VO slate sheets, which makes it possible to halve the number of joints during the construction of the roof.
Construction of a slate roof
Installation of a slate roof is carried out in the following way: for corrugated slate sheets, a base is created, which is a wooden frame made of bars:
- for a standard profile of slate sheets, the section of the bars is 5x5 centimeters, the pitch of the crate is from 50 to 55 centimeters;
- for a reinforced profile of slate sheets, bars with a section of 7.5x7.5 centimeters are taken, while the step of the crate is from 75 to 80 centimeters.
When installing a slate roof, the sheets should be laid sequentially, starting from the eaves and gradually moving towards the ridge.
Before laying slate sheets, it is recommended to lay a layer of roofing material on the crate, which will significantly improve the quality of roof insulation.
The release of the overlying rows to the lower rows should be approximately 12-14 centimeters, although at an angle of inclination of the slopes exceeding 30º, an overlap value of 10 centimeters is allowed.
In addition, the seams should be offset in the longitudinal direction by a distance equal to the size of the wave of the next row of material. Nails can be used to fasten slate sheets, but it is recommended to use screws with galvanized washers.
Important: to ensure the tightness of the fasteners under the screws, it is recommended to install special gaskets (the most suitable material is rubber) to prevent roof leaks at the places where the screws are screwed.
For the manufacture of cornice overhangs, materials such as roofing metal or asbestos cement can be used.
Painting a slate roof
Slate painting is done in order to improve its quality and appearance of the roof.
For this, special paints are used, which form a protective layer on the surface of the slate, which prevents the material from cracking, significantly reduces the absorption of moisture and increases the resistance of the slate to low temperatures.
In addition, the coloring of slate prevents the release of asbestos into the ambient air and doubles the life of the roofing.
For coloring slate roofs two types of colors are used.
- Water-dispersion paints, also called acrylic, have the following advantages:
- They close all microcracks on the surface of the slate, preventing moisture from passing through them, which significantly increases the life of the roof;
- They make the slate coating hydrophobic, which leads to more efficient drainage of moisture. This allows the use of this material when covering flat roofs with a small slope angle.
- Reduce the load on the truss system due to more efficient snowmelt in the winter.
- Alkyd paints dry fairly quickly, and also have the following positive qualities:
- Significantly higher viscosity than conventional paint, due to which the painted surface is smoother as a result, and also has good resistance to external atmospheric influences.
- The coating after staining has good elasticity and no cracking.
- Special paint pigments help protect the painted surface from fading and other effects of sunlight.
Before proceeding with the painting of the slate roof, it is necessary to mix the composition properly, sometimes a solvent should also be added. Coloring is done in two layers with a brush or roller, while the air temperature should be from 5 to 30 degrees.
Important: it is not recommended to paint a slate roof during rain or under direct sunlight.
Slate roof repair
The technology for repairing a slate roof for small repairs, such as small cracks or chips, is a fairly simple and convenient procedure, at the same time extending the further life of the roof by ten years.
This will require PVA glue, cement grade M300 or higher, fluffed asbestos and water.
The mixture should be made in small portions, designed for two hours of work, using the following proportions: one part of cement for three parts of asbestos is diluted with PVA glue, diluted with water in a ratio of 1:1.
Important: the consistency of the resulting mixture should resemble sour cream.
Before you start repairing a slate roof, you should thoroughly clean it, removing various dirt and debris, and then wash the roof with a hose, paying special attention to places where there are cracks.
After drying do-it-yourself slate roofs it should be primed with a mixture of PVA glue and water, diluted in a ratio of 1: 3.
Next, carefully, in two passes, paint those parts of the roof on which the formation of cracks is observed, which will also improve the thermal insulation of the roof. So the main slate roof repair Completed by you.
Important: when applying the mixture to the roofing, make sure that the thickness of the resulting layer is at least two millimeters. In addition, you should not repair the slate roof in sunny weather.
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