Shop roof insulation question--

[Youngfd]

My goal for 2015 is to enclose the open 24' x 36' portion of my shop. It currently has a metal roof and with our WASH. climate it is "raining" inside from condensation. This spring I plan to tear off the old metal and put down plywood, next I will roll out a special membrane material (forgot product name) and then will install a new metal roof. I am thinking about insulating it now with 2" foil back rigid insulation. Installed flush with the bottom of the 2" x 6"'s. That would give me a 3 1/2" air gap between the insulation and the metal. Any thoughts on using this insulation in the ceiling? Jim

 

[ford33]

It appears the roof does not have much of a pitch. Is it almost flat? I am not a professional roofer and professionals will provide a better answer.

If you put plywood down on a nearly flat roof, it will just get wet and will not last?

Putting plywood under the rafter is not going to fix the problem. If it is "raining inside" now how is plywood going to stop that from happening? The water will fill run on top of the plywood until it find a hole.

I believe you need to consider the design and construction of the existing roof and whether it is advisable to enclose the structure.

 

[rburke65]

I'm thinking what ford33 said. Not much of a pitch there....or does not appear to be. If it's all opened to the elements, why is it not raining outside? I do not understand.

 

[dfiler2]

I believe what he is saying is he has a problem with condensation, in fact that's exactly what he said. Assuming you will be heating the area your idea makes sense. Using the 2" foil back insulation flush with the bottom of the 2x6 roof should work fine. The 3 1/2" air gap will help keep the condensation from occurring in that area.

 

[Youngfd]

Yes, plenty of pitch on the roof. Plywood will go on top under the new sheet metal. J