Quoting from our architect's notes
'...Insulate fully between rafters with Kingspan K7 or equivalent, with 62.5mm of Kingspan K18 beneath rafters...'
That suggests that somewhere there is a performance equivalence table. But there isn't is there? There seem to be equivalence claims (often unverifiable, it seems)
This is the closest I got. Anyone help me do better, please? Specifically, what is the equivalent of Kingspan K7?