Guest User
11/11/2002
Would it be ok to install double foil faced 1 inch polyisocyanurate insulation directly on top of my sheetrock in the attic? I have quite a bit left over from another project. My concern is, moisture accumulation between the sheetrock and the foil. Some contractors say I will get moisture that will cause problems, and others say it will not accumulate moisture. Of course, I will add about 20 inches of blow in fiberglass on top of this rigid insulation. Thanks, Mark
Allan Reid
Dura-Loc Roofing Systems, Inc.
11/11/2002
In previous communications you had already installed your insulation and had venting problems. As well we talked about proper roof assemblies. I don't think we can help you any more. This is a free service to help people with real needs about metal roofing. Thanks.
Guest User
11/12/2002
You wrote: I don't understand why the US is so far behind the rest of the world on air barriers. I would suggest a number of fixes. You are right on the paint however an oil base has substantially lower perm numbers. Next, remove the baseboard and caulk the drywall to the floor and paint over it. Next, shut the power, pull the plugs and switches and spray foam through the holes in the boxes all around if possible. Next remove the trim at the window, foam in and paint over to super seal it. Al, I assumed, by you saying air barriers, you meant vapor barriers. I must have assumed wrong. And yes, there is blown in attic insulation, but I have 36 bails of bagged fiber glass insulation in the garage waiting to be blow in on top of the existing. You gave me a number of 60/40 for a maximum ratio of ridge venting to soffit/gable venting. Our venting is very close to this number, so I'm assuming it's ok to have a little more ridge venting than soffit/eave venting. I thought while I could still sweep the fiberglass blown in, into piles exposing the ceiling, it would be a good time to add a vapor barrier. Maybe not. I realize this is a metal roofing forum, and not a whole house forum, but ventilation and vapor barriers can affect the roofing system, and ventilation can be affected by the roofing system. I also realize this is a free service to help people with real needs about metal roofing. Although this Web Site makes no guarantees about recommending a roofing company, ATSCO was found at this Web Site. My new metal roofing installation was not done very well, based on feedback from real metal roofing experts and metal roofing commonly accepted industry standard installation practices. I greatly appreciate all your help! My roofing installation is not complete, and I (the homeowner) will have to complete this project. That's why I came here for help. It's becoming winter time in Montana, and I have gutters to install. Before they can be installed, I must inject silicone sealant between the metal panels and the eave flashing, between the metal panels and the valley flashing, and the rib ends of all the standing seams, to prevent ice dam problems this winter. It's cold and windy nearly everyday, so this is not a fun task, but a necessary one. If you don't think the instructions in the Metal Sales Installation Guide are important to follow, and based on my punch list, I have a perfectly adequate installation, then you are 100 percent correct that I have no real needs here. Best Regards, Mark
Guest User
1/11/2007
I am in New Jersey. I have a Barn Board ceiling on the second floor of an old home. There is a metal roof with very little pitch. There is 2-3" of poly-foam insulation over this ceiling. We are having a condensation issue in the A.M. when it is cold.The air circulation seems to be adequate. The metal roof is on furring strips over tar paper over sheathing. the condensation is only in the middle portion of a 40x12 section of the house. Do we need a better vapor barrier between the metal roof and the sheathing or a better vapor barrier between the sheathing and the ceiling? Or something else? Thank you.
Todd Miller
Classic Products, Inc.
1/13/2007
I would suggest a vapor barrier behind the ceiling. However, I also must question whether you really have good ventilation occurring with intake and exhaust.
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