I have a large 16mx7m shed/workshop ,walls single skin blockwork and roof is square section Alugalv roofing sheets. Great to work in except in cold weather, especially after a frosty spell, when the thaw comes it drips everywhere. So I need to insulate . Is there some kind of spray on foam which I could use on the underside of the roof?. Alternatively I was considering lining the roof with insulation board of some kind, but I would need to be able to fix it somehow. I don't mind spending a bit of cash on it as I have tools and cars which need to be kept dry.