ITALIAN SLATE Chemical and technical features |
Italian slate is a schistose rock whose chemical composition is characterized by: - 22% silica which makes slate strong, durable and very suitable for floors and staircases. - 21% calcium oxide; it doesn’t make slate resistant to any type of acid which produces white spots on the surface. It’s because of the acid components in the rain that slate fades into grey when used outside. We can supply a suitable emulsion which is particularly appropriate for treating slate surfaces used in furnishing in order to prevent spots due to lemon drops, for instance, or to any other acid liquid. For roofing, external floors and cladding no treatment is necessary. In the natural cleft finish, slate may have slight irregular thickness but you can solve this problem using a suitable quantity of chemical adhesive during the laying. For cleft both faces tiles, thickness may vary from + 5 mm. to – 5 mm. In order to have a more uniform thickness we recommend to choose cleft/calibrated tiles. DEFECTS : White veins which are a foreign matter (quartz) and may cause cracks.
Cracks
– when the material gets wet, cracks appear on the slabs; they can be
quite large and run in any direction across the surface of the slab . |