Anyone know what this is? Pulled from a skip several years ago, it's been sitting in my garage but will now go into the shed ceiling. Looks like celo/k'span but instead of foiled it's got a layer of grey felt with holes in. Probably glass fibre based cos it's itchy. I was thinking the grey stuff is some kind of sound attenuation, but rigid board is crapola for soundproofing so maybe not. I've never seen it in any building suppliers, any ideas?
