Slate Roofing
Just like any other shingled roof, the slate shingle roof consists of overlapping small surface plain parts made of natural slate or imitation slate-like materials (e.g. rubber slate roofing).
The water is drained down/away off the roof as the slate shingles are being installed under certain slope. If there was just the hydrostatic pressure (no pitch), the slate tiles would let the water through (slate tiles are not suitable for low slope or
flat roofs as they would very probably sink).
Slate roofing materials
For sure, the most used of all slate roofing materials is the natural slate which is a reliable, simply cleavable, weather-stable mineral of a fine structure.
The color of the natural slate roofing depends on the location where the slate was mined. Generally, you can buy slate shingles in many natural colors ranging from gray, through gray-green or gray-blue to black.
The thickness of particular slate roofing shingles is not stable as they are handmade and it ranges between 4 - 8 mm (slate shingles thinner than 4 mm tend to break, the thicker slate shingles weigh too much and require special
roof truss construction).
Maximum (useful) dimensions of one slate roofing tile is 60 x 30 cm.
Slate roof installation
When installing the slate roofing shingles onto the underlaying construction we use special
nails and slate roofing fasteners, both made from materials that donīt suffer from corrosion (zinc-coated steel, galvanized steel or copper).
Slate shingles can be laid directly on the sheathing plunks, or the plunks/counterplunks construction that creates also the necessary ventilation space. In windy and dusty areas you can cover the sheathing first with the sanded asphalt sheet in order to prevent the dust or dusty snow intrusion.
The minimum slope of the roof shingled with the natural slate roofing shingles
The minimum slope of the roof necessary for the natural slate roofing is 30 degrees (with the waterproof underlayment from 20 degrees).
If you use any of the lightweight imitation slate roofing materials, the minimum pitch is lower (asphalt roofing shingles from 20 degrees and asphalt-fibre composite roofing shingles even from 15 degrees).
Slate shingled roof has to be completed with sheet-metal components like ridges, gutters, vents, flashings, fascias, etc... in order to guarantee itīs non-problematic functionality.
