TOPIC: I Have An Existing Metal Roof and Have A Question
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It must be the flashing problem according to me, can be done easily but for that you must hire a professional and ask them to check and fix the leakage issue.
I have a 14x70 swmh with metal walls and roof that has been gutted and is now going back together. I had some roof seams that were leaking and repaired them with Gaco roof tape followed by three coats of Gaco roof coating on the entire roof. The interior had no insulation so I was able to verify the leaks were cured. However, I recently insulated using Owens-Corning kraft-faced insulation; R13 for the walls, R30 for the ceiling. The ceiling is a combination of vaulted and flat. Where it's vaulted, there is no air gap between the ceiling and insulation but where it's flat there is an air gap. I am now seeing moisture on the insulation facing where the flat and vaulted sections meet. There was no rain when this was discovered; in fact it was dry at 9 in the morning but damp by noon. This is on a very hot and humid day. No A/C was being used so there was certainly no cool air present. Is this a condensation issue and if so how do I alleviate it?
The ceiling needs an air barrier via drywall or some other sort of seamless air barrier.
I followed the link you sent -- thank you very much. So I need to install drywall and then seal it at the places they recommend. But can I do that if the insulation is damp? Doesn't it have to be dried out first?
Needs to be dried out. You need to condition that space and get it dried out first and be sure there is no moisture behind it.
Have you ever seen this happen before? We've been reading a lot trying to find out what's going on and we're getting a lot of conflicting information. We just want to be sure we address the true cause of the issue before we go any further.
Here are some of the photos we took once we found it wet.
Just a reminder, it was dry at 9am and wet by noon. It didn't rain at all today.
We just finished insulation last week and we saw no problems at that time. We even went to the trailer twice during heavy storms to look for leaks well before we put insulation up.
If warm moist air reaches a cool surface, it will condense. What's happening is that warm moist air is reaching the cold back side of the home's exterior and condensing. Avoiding condensation requires at least two of the following three things, and preferably all three: Vapor Barrier, Insulation, Ventilation.
But that's not what's happening. There's no cool surface. In fact, the roof was quite hot when the problem surfaced. The inside air was humid to be sure but it too was very warm. At least 90° F. I don't understand how condensation can cause that big a damp area.
Interesting. As I recall, at 90 degrees, if humidity is 65%, condensation will occur. Your photos didn't post for some reason. I am sorry. Would you wish to email them to me at [email protected]
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