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TOPIC: General Discussion

How to stop condensation with a metal roof

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I'm sure you have answered this question before but if you would please answer it again. We placed a metal roof over our existing roof (flat mobile home roof), raising it up to have a pitch on it. To our surprise we had condensation to the extent it began to damage our ceilings. We have installed fans, but to the question. Is there a spray foam insulation that a homeowner can do themselves or any other suggestions to prevent this again as we head into winter? Thank you DS
Deb S

11/4/2005
Condensation occurs when warm moist air hits a cool surface. One of the most effective ways to stop it in your case would be to have good ventilation with intake air at the bottom of the roof, traveling up the back side of the roofing panels and exhausting out of a ridge vent at the peak. Better insulation on top of the ceilings could play a role. Yes, there are spray-on insulations that could go on the back of the roofing but unless you have a way of making certain that that is completely airtight so that no moisture gets in between the insulation and the roofing panel, I would not try it. Todd Miller
Todd Miller
Isaiah Industries, Inc.

11/4/2005
Alright I understand the ventilation installation system. The spray foam insulation unless as you stated we get it airtight it is pointless to do. Would doing both be overkill? Or would the ventilation way make it impossible for the roof to be airtight? If my husband chooses to do the foam insulation do you recommend a particular type?
Deb S

11/4/2005
You would want to use an icynene insulation, or other closed cell insulation. I would suggest discussing this with the insulation manufacturer and see what they suggest as far as ventilation. I think they will tell you to not use ventilation. Todd Miller
Todd Miller
Isaiah Industries, Inc.

11/4/2005