TOPIC: I Have An Existing Metal Roof and Have A Question
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I have a mobile home with an existing metal roof. The hot water heater burst and got most of the home wet and a lot of the insulation turned loose from the metal on the underside. I have tried to replace all of it I can and have new sheetrock up but now am seeing wet spots at a lot of places. I took down some of the sheetrock and it is real wet behind it against the metal. What I am thinking about doing is putting 3/4" insulation board on the top then stripping it with 1 x 4s and putting on a new metal roof. Will this stop the sweating?
I am a little unclear -- was everything okay before the water heater incident? What else changed to cause the condensation? Generally speaking, condensation in a roof system is controlled by:
1) Sealing all air leaks from the living space
2) Vapor barrier behind the drywall
3) Insulation on top of the vapor barrier
4) Active ventilation
5) Thermal breaks
You need several of the above to be successful.
Yes everything was ok before the water heater burst. The people living there were gone for several months when the heater burst. This is a rental. My thinking is all the moisture made a lot of the insulation turn loose from the metal. I had a guy replace a lot of the sheetrock but he didn't replace the insulation like he should have. I have tried to take some of the sheetrock down and get insulation in as best as we can but still have the sweating from where there are places that don't have insulation against the metal. I talked to the guy from the metal place and he had insulation that come in rolls 4' X 125' that he says has r14 value. I am thinking about putting this on the roof then putting 1 x 4 strips over it then the metal. Do you think this will fix the problem?
Thanks. I have a better understanding now. I am not entirely sure what sort of insulation was applied to the metal. However, most insulation allows moisture to pass through it. This would create a situation where condensation is occurring, just hidden by the insulation. Would there be a way to put in insulation and have a complete vapor barrier on the warm side of it? Another option would be closed cell urethane spray foam which acts as a vapor barrier and an insulator.
At this point it would be really costly to put any kind of insulation on the inside. I would have to tear out all the sheetrock to do it. I have spent over $10,000.00 so far and can't afford to keep spending on it. The original insulation against the metal looks like regular bat insulation that is either glued or put up with paper strips. It is about 2" in thickness. I have r 19 in most of the places above the sheetrock. Since I can't really get insulation on the inside I thought the next best thing would be to put it on the outside. I'm just trying to come up with the least expensive way to go. I've had 9 or 10 different contractors working on the mobile home and had to fire most of them or either they did a terrible job and I found out about it later. The last guy didn't put the insulation behind the sheetrock and I had to take a 2' strip of sheetrock down to try to get the insulation in. I have been trying to get this mobile home fixed since last March.
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