John C Daley wrote:Ben, what does this mean please?
where the furring is
Aso, we dont use gauge as a measure of thickness much nowadays, do you know the mm size?
25g = .531 mm
26g = .455 mm
29g = .343 mm
I prefer to install metal onto 2"x4" (1.5"x3.5") furring, that is fastened either to the rafters, or on top of sheathing if the client so chooses. I find that installing metal directly onto sheathing (OSB or plywood), does not hold good. The screws will tend to back out of the thin sheeting easier than a 2x4. I have had to re-screw roofs that were fastened only into OSB.
Also it goes without saying that a vapor barrier is needed to help with the metal sweating, and that is even with the insulation in the attic!