SLATE.

Natural Slate has some beautiful colours in it and can look stunning when fixed correctly, however there are lots of different grades of Slate.

Some Slate can be almost warped in appearence due to the way it was formed millions of years ago, this can pose problems to the installers as they will use almost double the amount of adhesive to acheive a solid fixing, so it is well worth finding a decent graded Slate by checking with the supplier