Al T

I thought it was either 2 layers of normal plasterboard or 1 layer of fireline stuff

Yes I'll be plasterboarding the garage ceiling with the fireline plasterboard

Hi everyone. I'm after some advice. I've just had an extension built that has an unheated garage with a bedroom above it. I know this can cause the bedroom to be cold. What is the best way to insulate the garage ceiling? I was going to use 200mm of the rock wool. Do i need to leave an air gap between the top of the insulation and the bedroom floor? TIA Al