Felt Paper Used As Insulation???

Age

Im new to the building scene but plan on getting my GC within the next few years. I am doing a job for a guy and he wants me to put 15# felt paper on the inside (over the existing furring strips) of an exterior block wall for the purpose of insulation. I suggested e use the R-MAX type foam sheathing but the owner said it was too expensive and the guy I work for suggested this instead.

My question is will this be effective as insulation, I thought the felt paper was a vapor barrier and I can't see it having any kind of significant R value.

Your thoughts please.

reveivl

It has no significant r-value. This guy is dreaming in technicolour.

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joasis

I thought I had heard it all......if he wants the vapor barrier, there are far more effective ways to accomplish that purpose. You might suggest an insulation called foil back, or double bubble...20 some odd cents a square foot, and can be edge taped.

Age

Yeah I think he's trying to cut corners as he has a bunch of leftover rolls of felt lying around. Im going to pursuade the owner to get some 3/4'' foam board.

Another question, when installing the 3/4'' board, is it best to fill the gaps between the furring or place it right over the furring strips? ive seen it done both ways. Also if place over the strips, whats the best fasteners to use, cap nails often get in the way when screwing drywall on.

joedonuts

i think the best way to go about it is to install the foam board between the studs. if you install over the studs it may trap moisture and possibly rot the studs over time.

Grumpy

Felt paper can be used as a vapor barrier, but I fail to see any legitiimate way to use it as an insulation. Perhaps you misunderstood your builder or perhaps your builder said insulation meaning vapor barrier, or perhaps this is the first time your builder has been on a job site.

RYANINMICHIGAN

in short, no way....

reveivl

"or perhaps this is the first time your builder has been on a job site."


Hahahahahahahaha

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tcleve4911

Felt is not a vapor barrier & has no R factor. Build rite. Know your products

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Tscarborough

Felt paper should work fine as insulation....Just be sure to put it on 3-4 inches thick.