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TOPIC: Insulation Concerns

metal on new house

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we just put down metal roofing and ordered every thing we needed, but now we hear that we should of put down insulation first, we did not put down any, its on open or space boards, no sheeting, we thought we could put insulation just on top of our dry wall, it this ok, or do we need to put some kind of insulation under the metal through the craw space, thanks Kbird
Guest User

9/16/2005
What you're doing is appropriate for many metal roofs, even though it may not be my personally preferred method. I assume that your metal panels were approved for installation over spaced sheathing. Actually, I would not have suggested insulation necessarily but probably solid decking and underlayment. Anyway, here's my suggestion at this point. A vapor barrier behind the ceiling drywall -- to keep moisture from inside the home from transferring to the attic where it could condense on the back of the metal roof. Good insulation on top of the vapor barrier then, in the attic floor. And, finally, good and proper ventilation with soffit vents for intake and a ridge vent in the metal roof for exhaust. Todd Miller
Todd Miller
Isaiah Industries, Inc.

9/17/2005
ok confused, lets take it backwards, the drywall ceiling then the insulation then the vapor barrier, the silver insulation, right, and do we put it on the rafters also, for we are not putting drywall in the crawl space? also do we put down insulation on the rafters then the vapor barrier. Thanks so much Kay
Guest User

9/24/2005
From the inside out, here is the order of things which I prefer: Drywall, vapor barrier, insulation, vented airspace, decking, underlayment, roofing. The point of the vapor barrier is to keep moisture out of the insulation and out of the attic as well. Insulation should be down on top of the ceilings. You need the space between the rafters (beneath the roofing) to be ventilated. You want to be bringing in air at the eaves and exhausting it out at the ridge. This helps avoid condensation and excessive heat build-up in the attic. Todd Miller
Todd Miller
Isaiah Industries, Inc.

9/25/2005
ok, since we don't have decking and underlayment, it should be vented ok, right, and then put down the vapor barrier and then insulation on top of the ceiling, sorry it gets us so confused when we hear different ways. And is the vapor barrier the silver insulation, or is it just called that. And do we need to put in a exsust fan, thanks for helping us, and having patience with me. Kay
Guest User

9/25/2005
Some indulation products, if properly installed (which usually involves taping or sealing the seams, can have a vapor barrier on them. However, in your case, I would use polyethylene sheeting as the vapor barrier behind the drywall and then insulation on top of that. One of the most effective ways to vent is by having soffit vents at the eaves as intake and then a continuous ridge vent as exhaust. That provides good natural, convective airflow to help accomplish the ventilation. Generally, adding a power vent or something to this sytem will disrupt the airflow and not be beneficial. Todd Miller
Todd Miller
Isaiah Industries, Inc.

9/25/2005
thank you ever so much, you have cleared up a lot of our worries, because we was told the metal would sweat and give us leaks, if didn't do it right, again thank you very much, and God Bless, Kay
Guest User

9/25/2005
You're welcome. Good luck Todd Miller
Todd Miller
Isaiah Industries, Inc.

9/26/2005