How to properly fix the slate on the roof?

Slate remains one of the most popular roofing materials in private construction due to its affordability, durability and ease of installation. Correct fixing of the slate on the roof provides reliable protection of the house against precipitation, wind and snow for many years. In this article, we will consider in detail all stages of work, starting from preparation and ending with final recommendations for operation. Despite its apparent simplicity, installation of slate requires compliance with technology. Errors during fastening can lead to leaks, deformation of sheets and premature destruction of the roof. We will cover the basic rules, tools, materials and common mistakes. By following the instructions, you will be able to do the job well even without much experience.

 

Asbestos-cement slate is characterized by high bending strength, resistance to temperature changes and fire resistance. It does not rot, does not corrode and withstands snow loads well. Modern slate is produced in various profiles: wavy, flat, with a reinforced wave. The average service life of high-quality slate is 30-50 years, provided it is installed correctly.

However, the material has its drawbacks: relatively heavy weight, fragility in case of point impacts and the content of asbestos in some types (although chrysotile-cement version is more often used now). When working with slate, be sure to use personal protective equipment to avoid dust entering the respiratory tract.

Before starting work, make an accurate calculation of the number of sheets. The standard size of corrugated slate for 8 waves is 1130x1750 mm. Take into account the overlap: lateral is usually 1-2 waves, longitudinal - 150-200 mm depending on the slope of the roof. For roofs with a slope of less than 20 degrees, the overlap is increased.

You will also need fasteners: special slate nails with a wide cap or self-tapping screws with a rubber gasket. Waterproofing film, bars for the crate, ridge elements, valleys and joints - all this must be prepared in advance.

For work, you will need the following set: a hammer, a hacksaw or a grinder with a stone disc, a drill, a tape measure, a level, a cord for marking, a ladder or scaffolding. It is advisable to have protective glasses, a respirator and gloves. A grinder greatly speeds up the cutting process, but it creates a lot of dust, so work outdoors.

A reliable crate is the basis of a quality roof. For slate, a rarefied crate of 50x50 mm bars or boards is used. The step of the crate depends on the length of the sheet: usually the bars are arranged so that each sheet rests on at least three points.

A waterproofing membrane is first laid on the rafters. It protects wooden elements from condensation. Then the counter-crate and the main crate are attached. Treat all wooden parts with an antiseptic and fire bioprotection to extend the service life.

The optimal slope for a slate roof is from 20 to 45 degrees. With a smaller slope, the risk of leaks increases, with a larger one, material consumption and wind load increase. Check the geometry of the rafter system: all planes must be even, otherwise the sheets will lie with gaps.

Installation starts from the bottom row from the eaves. The first sheet is aligned along the cord to ensure an even line. Each subsequent sheet is laid with a flap. Fastening is performed in the upper part of the wave so that water does not flow under the cap of the nail.

It is important not to overtighten the fasteners: slate is fragile, excessive force will lead to cracks. A small gap of 1-2 mm is left between the cap and the sheet. Holes for nails are pre-drilled with a diameter slightly larger than the thickness of the nail. This compensates for temperature expansion.

Bituminous mastic or special tapes are used to seal the joints. Shaped elements are installed on the ridge and ribs, also attaching them to the crate.

There are several ways: with an offset of half a sheet or without an offset. The first option is better because it minimizes the number of four-corner joints, where leaks most often occur. Slate is cut according to the markings, trying to minimize the number of scraps.

In regions with strong winds, the fastenings at the edges and on the ridge are additionally strengthened. Use more attachment points. In snowy areas, the crate is reinforced and snow arresters are provided to prevent avalanche-like snow that can damage overhangs.

During the repair of the old roof, the crate is carefully inspected. Replace damaged bars. Old sheets are removed carefully so as not to damage the rafters.

  • Always drill holes, do not drive nails directly.
  • Fasten the sheets only in the crest of the wave.
  • Follow the recommended overlaps depending on the slope.
  • Work in dry, windless weather.
  • Use only galvanized or special fasteners.
Parameter Value
Slate nail size 70-120 mm
Crate step 400-750 mm
Side flap 1-2 waves
Longitudinal overlap 150-200 mm

One of the main mistakes is the incorrect step of the crate, which causes the sheets to sag or crack under the load. Many beginners drive nails too hard or into the bottom of the wave, which leads to leaks. Insufficient ventilation of the under-roof space causes condensation and rotting of wood.

Avoid installing slate on an old roof without checking its load-bearing capacity. Do not skimp on waterproofing. After installation, be sure to check all joints for tightness.

Properly fixed slate requires minimal maintenance. Once every 2-3 years, inspect the roof, clean it of leaves and moss. Moss is removed by special means or mechanically. When cracks appear, they are covered with cement-based repair mixtures with the addition of PVA glue.

Timely repairs extend the service life of the roof. Do not walk on the slate unnecessarily: use special ladders or boards to distribute weight.

Perform work at height with insurance. Use stable scaffolding or ladders with latches. Protect skin and eyes from cement dust. When cutting with a grinder, wear a respirator - inhaling asbestos dust is harmful to health.

Follow the safety precautions and the installation will be injury-free. If the roof is of a complex shape or the height is high, it is better to entrust the work to professional roofers.

Correct fixing of slate on the roof is the key to durability and tightness of your house. By following the described technology, choosing quality materials and carefully performing each stage, you will get a reliable roof that will last for decades. Regular inspection and timely care will help to avoid expensive repairs in the future.

Remember: savings on fastening or waterproofing often turn into higher costs later. Approach the matter responsibly, and the result will please you.