Fire: Crest Natural Slates are non-combustible

Water Resistance: The water absorption level is within the limits set down by BS680: Part 2: 1971. The slates also comply to this standard for delamination, spitting and flaking when subjected to wetting and drying tests.

Chemical and Biological Resistance: Chemical and Biological Resistance: Unaffected by the sulphuric acid immersion test of BS680: Part2: 1971. Unaffected by chemicals in other building materials and pest and insect attack.

Durability: The life of a Crest Natural Slate will normally exceed that of the actual building itself.

Storage and Handling: All slates are supplied in wooden pallets but any loose slates should be stacked carefully on their longer edges, ensuring that the bottom layer is on a firm level surface. Timber battens should be placed between layer. All slates should be handled carefully on site.

Cutting and Holing: This can be done by mechanical disc cutter or hand operated cutter. Holing can be done at source or on site.

Good Roofing Practice: Slates should be fixed in accordance with B.S. code of practice for slates and tiles BS5584: Part1. B.S. code of practice for workmanship on site, BS8000: Part 6: 1990 should be referred to.

Underlay: Roofing felt should be used and we recommend Crest Interfol, Standard or micro-perforated. Interperm 140 is also available for warm roofs.

Battens: 50 x 25mm battens are recommended, treated, not less than 1200mm in length, and free of any sign of decay, insect attack, knots or knot holes.