"Goedjn" wrote in message
...
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.

--Goedjn



If the edges are in good shape and they are not spalling or delaminating
(splitting along the layers) and the nailing holes are intact, I'd say they
are servicable.

Try soaking one in water and freezing in the fridge overnight to see how it
stands up if they look porous (they should not).

Installed properly, they will last a heck of a lot longer than cheap ass
shingles. Could be a big win for you.