The foam should provide the thermal break and ideally control the migration of any conditioned air to the cold side of the roof.
No need to have installed any additional vapor control layer depending on the type and installation of foam.
Eric Novotny
2016-12-23 08:09:12.000000
I have an older double wide mobile home which had an original roof made of thin metal coil.
The owner before me did a roof over with 3/8" plywood nailed to the roof trusses through the original metal roof, then had mineral roll roofing installed over the plywood.
After I bought the mobile home I had the mineral roll roofing and the plywood under it removed and had a new Insulated Aluminum Cap Sheet Roof, installed. The Insulated Aluminum Cap Sheet roof has a 2x4 around the roof perimeter with 2" rigid foam insulation filling the entire roof area inside that 2x4 perimeter, and aluminum coil roofing installed over it.
The removal of the plywood left numerous nail holes through the original roof and the contractor did not fill them (too many), Nor did he lay down any sort of waterproof membrane under the rigid foam insulation.
In the area where I live we have many very damp nights, with heavy condensation frequently forming underneath my Aluminum Carport and Patio covers. I am concerned I may have a condensation problem under the new Aluminum roof as well, and moisture could be forming and dripping into and through the old nail holes and into my attic.
Should some sort of plastic or other type moisture barrier membrane have been stretched out on the old holy roof before the new roof system was installed?
Thanks for your help.
John Tschogl
jayshaygull@gmail.com
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