Grades Of Roofing Slate

Grade s1 slate has an expected service life of more than 75 years.

Grades of roofing slate. Slate from cupa 5 and 18 quarries have more of a textured finish. N is cupa s natural selection. Grade s2 slate s service life is 40 to 75 years. 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. Roofing slates are rated through the american standards of testing and materials and given a slate classification from s 1 to s 3. Standard grade rough texture. This further highlights the traditional regional variations.

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. S 1 will provide a service life of over 75 years s 2 will provide a service life of 40 75 years. Grade s3 slate has an expected service life of only 20 to 40 years.

Greenstone slate is measured by eye to thickness and is then split by hand.