Grades Of Roofing Slate

Grade s2 slate s service life is 40 to 75 years.

Grades of roofing slate.

Grade s3 slate has an expected service life of only 20 to 40 years. Roofing slates are rated through the american standards of testing and materials and given a slate classification from s 1 to s 3. S 1 will provide a service life of over 75 years s 2 will provide a service life of 40 75 years. Slate grades are intended as a prediction of the slates expected service life.

According to astm test c 406 roofing slate falls into three grades of classifications. Welsh slate being very flat and smooth as well as a nominal 5mm thickness. Slate from cupa 5 and 18 quarries have more of a textured finish. Grade s1 slate has an expected service life of more than 75 years.

Welsh slate still comes in 3 grades referred to as capital 5 5mm thick county 7 mm thick and celtic 9 mm thick. It is truly the result of a craftsmen s. Standard grade rough texture. A standard grade slate cupa h selection will be less uniform and will require more sorting prior to use.

This further highlights the traditional regional variations.