Goedjn wrote:
Does anyone know of an objective way to decide whether
a salvaged roofing slate is in useable condition or not?
I've got a whole pile of them in my basement,
so they're free; if they'll last as long as a cheap-ass
asphalt shingle, that's a win for me, because it means
I don't have to replace the skip-sheathing with plywood.

Rap each one with your knuckles. The good ones will ring and the bad
ones will sound flat.

r