Vapor Barrier?

[jrbridges]

Another roofing question folks. Thanks for your patience. I keep hearing conflicting information.

I have 7/16 inch plywood on my rafters and will be putting a metal roof on. It seems to me that a vapor barrier would be a good idea, right? (Something between the plywood and the metal roof)

What type of material would be advisable? 45# tar paper? Picture is attached and I have the roofing on order.

[3rdgen.maple]

jrbridges contact the manufacturer of your steel roof. When I put a new roof on the garage in order to NOT void the warranty they required 90lb roofing paper when the roof is sheated. They will have the correct answer you need.

[Dave Y]

jrbridges,
When I put my metal roof over the sheathing on my sugar house, I put a product call snow and ice gard on it first. It will stick to the sheathing and will not leak thru if one of your screw washers fail. it is more expensive but worth it.

[jrbridges]

Thanks for the tips. Part of the reason I'm getting conflicting information from building suppliers/hardware folks is that they are unfamiliar about the conditions in a sugarhouse and they are simply relaying manufacturers recommendations for "normal" structures. I am going to look into that Snow and Ice material.

[3rdgen.maple]

jrbridges from what I understand the only concern with the metal roof is the expansion and contration from the changes in temperature that the roofing receives. As explained by the manufacturer to me it is those changes that causes rubbing on the nail or screw heads that hold the sheating down on the roof. The metal roofing material rubs on them and can cause premature wear. You should really check with the manufacturer of the product as they will give you the answer you need to not void the warranty on it.