denim insulation?


Old 11-20-14, 01:28 AM
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denim insulation?

anyone have good success or other experience with denim insulation? also does denim insulation have to not be smashed just like fiberglass can not be squeezed to tight to fit? is it ok for denim thats 15 inch wide to be squeezed into a a 14 1/4'' or so stud bay? last should i put plastic over it before drywall? if so what type of plastic?
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Old 11-20-14, 03:00 AM
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I am not that versed in the denim insulation, but if it is anything like Roxul, yes, slightly compressing it into the stud bay will help it to remain in place so you don't have to fasten it. Roxul requires no vapor barrier, is fire proof, water proof and mold proof, but it is a good idea to always install one on the warm side prior to final wall covering. 3 mil plastic is adequate.
Old 11-20-14, 04:40 AM
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I've never used it, but it looks to have the density of Roxul and the r-value of standard fiberglass, slightly below the value of high density fg.

You do want it to be compressed a bit, 15" into a 14.5 cavity as Chandler said and any you cut to fit needs that friction as well.

Air seal around electrical boxes and wiring penetrations and detail the insulation to fit as perfectly as possible. Neatness counts with insulation as random air pockets reduce insulation value.

As for the vapor barrier, in OH it is probably advisable, they say far north. The vb is another opportunity to improve the air barrier performance of the wall and as long as you have done a good job air sealing and are neat with the install it will be a plus. The negative potential of vb in your climate would be an air conditioned home with lots of air leaks. Those leaks would allow warm moist outside air to reach a cool inside surface and deposit some moisture. I'll add a link on whole house air sealing.

Old 11-20-14, 05:34 AM
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If your climate is anything like ours, and I assume it is, many builders are starting to omit the poly VB on the interior side. Many are finding better success with walls that can dry to both sides, whereas with a poly you get *no* drying to the inside and instead the poly becomes a location where condensation can take place. Its not surprising to find mold on the insulation side of the VB years later.

I can't explain what causes it, but walls with fiberglass insulation that I have examined while doing remodels with no VB or just a kraft faced vapor retarder often seem to fare better. Probably because things classified as vapor retarders will still allow "some" moisture to pass.

In some locations, inspectors will allow the latex paint on the drywall to be the vapor retarder. (see Vapor Barriers or Vapor Diffusion Retarders | Department of Energy)

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