New Garage Roof

[GOE1988]

Im renewing the roof on my garage, it measures 30ft x 15ft. Its a sloping roof, with joists ever 3 feet. Im planning to strip the corrugated sheets off the roof, and replace them with new ones.
This is the plan
1. Lay 12mm or 18mm plywood boards as decking on top of the joists, then lay a rubber membrane and tack it to the plywood, then lay 16ft corrugated sheets on top.

My question is what type of membrane is best to use under the roofing sheets?

thanks

 

[marshman]

roofing felt

 

[vinty]

If you redeck your roof and cover it with a rubber membrane why are you putting the corrugated sheets back on again? to secure your sheets you are either going have to nail or screw them to the deck which means you will puncture the membrane across the whole roof.
Rubber membrane is a flat roof covering in itself, you can use either firestone epdm or butyl rubber and stick it directly onto the deck using contact adhesive, these membranes can last up to 30 years.

 

[martyc]

Agree with vinty,
However if you put down say 18mm OSB with the corrugated stuff on top(no membranes) you should have a very strong and long lasting roof.
Did this on my mums garage 10 years ago and its working a treat.
Marty.