Q. What is slate composed of?
A. Slate is composed mainly of clay minerals or micas depending upon the degree of metamorphism to which it has been subjected. The original clay minerals in shale alter to micas with increasing levels of heat and pressure. Slate can also contain abundant quartz and small amounts of feldspar, calcite, pyrite, hematite and other minerals.
Q. What determines slate colour?
A. Most slates are grey in colour and in a range shades from light to dark grey. Slate also occurs in shades of green, red, black, purple and brown. The colour of slate is often determined by the amount and type of iron and organic material that are present in the rock.
Q. What is the life expectancy of a slate roof?
A. If used properly, a slate system will provide a long-lasting roof with a lifespan of around a century.
UNDERSTANDING CUPA SLATE GRADES
The result of a rigorous selection. Composed of exceptionally flat natural slates with uniform thickness. Simple and fast installation.
High-quality selected natural slates with slight flatness and thickness variations that meet or exceed all international standards.
Composed of natural slates with some flatness and thickness variations. This selection maintains the same quality standards, but requires an experienced roofer.
Exclusive hand-quarried 7-9mm thick natural slates. Incomparable HEAVY slates give any roof a unique and timeless rustic look.