Grades Of Roofing Slate

According to astm test c 406 roofing slate falls into three grades of classifications.

Grades of roofing slate.

Greenstone slate is measured by eye to thickness and is then split by hand. S 1 will provide a service life of over 75 years s 2 will provide a service life of 40 75 years. Standard grade rough texture. A standard grade slate cupa h selection will be less uniform and will require more sorting prior to use.

Slate grades are intended as a prediction of the slates expected service life. Roofing slates are rated through the american standards of testing and materials and given a slate classification from s 1 to s 3. Slate from cupa 5 and 18 quarries have more of a textured finish. But the finished project will look as good if due care is taken of the slate grading.

Grade s2 slate s service life is 40 to 75 years. Grade s1 slate has an expected service life of more than 75 years. It is truly the result of a craftsmen s. This further highlights the traditional regional variations.

Grade s3 slate has an expected service life of only 20 to 40 years.