wet insulation

[dan orourke]

........

[Joseph Michalski]

Owens Corning, and other sources I have used in researching the same question say "no."

Save Energy: Question: Should I replace wet insulation? (http://saveenergy.owenscorningblog.com/2006/08/question_should_i_replace_wet.html)

The concept is that it temporarily loses R-value, but that it can be recovered. If mold growth, or dirt or debris trapped within the fibers is a possiblity, then it would seem that replacement would be appropriate.

[Mike Huppi]

It can be very bad if you have Knob and Tube. I had two homes last year that the insulation was hot when I tested it. Kinda scary

[Phillip Stojanik]

Fiberglass insulation can often be dried with little or no real permanent loss of R value. Cellulose insulation though tends to pack down and clump together after wetting and potentially reduces its R value more significantly and permanently once dried. It also possible that some of the borates added to the cellulose may be washed out by wetting and that can potentially change its intended anti-fungal properties.

Even fiberglass insulations though can stay wet long enough to create a mold problem on, or within, the insulation (when dirty) or on the surfaces they cover (particularly the paper backing of drywall). Drying contractors will often remove wet fiberglass insulation anyway in order to get to and dry other building materials covered by the insulation.

Once removed, its often not practical to try and put the old insulation back even if its been dried out. Its usually just cheaper to replace it with new once everything else has been dried and cleaned sufficiently.

[Scott Patterson]

when insulation gets wet, should it be replaced? I was thinking the R-value would be diminished.

Phillip covered it fairly well. It needs to be replaced in most situations. It is such a low cost building product when compared to the cost of tearing everything out if it does not dry properly and you end up with a mold farm.