Hi,
We had a new roof put on with a breathable membrane under the slate. We've opted for celotex insulation between joists/rafters and a second layer on top to get it up to spec. I had my suspicions and took a piece of the top layer off and sure enough none of it is either cut to friction fit not have the gaps been foam filled. I can fit my fingers in the gaps. Builders are telling me this fine.... I don't think it is. Am I right?