What stacking errors lead to cracks in the slate roof

The well-known and once popular roofing material - slate, is nowadays used less and less. And if earlier there was no alternative to it because of the availability and low price, then now its cost has almost equaled the corrugated board. In addition, slate is a very fragile material that requires compliance with a certain laying technology.

For the correct installation of the slate roof, the installation of a reliable crate from boards or bars is required. Boards must have a thickness of at least 2.5-3 cm, a square bar - a cross section of at least 6 cm.

Since slate is quite heavy material, the distance between the rafter elements should not exceed one meter. The interval between the boards of the battens should be at least 50-70 centimeters. In addition, the horizontal edges of the sheets must necessarily lie on the crate. Failure to comply with such parameters over time will lead to a deflection of the roof under its own weight and heavy snow. As a result, the slate becomes covered with cracks and ceases to fulfill its functions.

The roof crate is covered with waterproofing materials. For this, you can use a traditional roofing material or more modern waterproofing films. The waterproofing layer will prevent condensation from dripping to the ceiling of the house and protect against roof leakage in the event of slate breakdown.

The slate is laid in the usual way or with an offset. The first one is more economical. Sheets begin to lay from below in a row, from right to left. In this case, overlap is done in one wave. Then lay the next row with the overlapping of the lower sheets at a distance of 15-20 centimeters. In order not to cut the last row of slate, the length of the rafters is usually calculated in accordance with the dimensions of the sheets. If the length of the rafters does not match the dimensions of the slate, increase the length of the overlap of the sheets.

When laying slate with offset, the first row is laid in the usual way. All subsequent rows shift sideways by 2-3 waves. To do this, you have to trim the outer sheets. With this method, the consumption of roofing material increases markedly and the complexity of the work increases.

The most important point is the fastening of the slate to the crate. It can be carried out using special roofing nails or using long roofing screws with silicone washers. To avoid cracking, the sheets should be pre-drilled at the top of the wave. The holes should be 1-2 mm larger than the diameter of the fasteners.