I have a short living room wall (4'tall) in my split level exposed to
garage and thus to outside temps. Would like to insulate at lowest
possible cost. Looking into injected foam, way too expensive and the
material is not economically available for DIY. I have seen, on this
old house, contractors drill holes near the top of walls between each
stud and fill with cellulose, blown in. Sounds crazy, but what about
Drill same kind of holes, then slowly fill with popcorn packing
material, NOT the water soluble kind. Free material, shipped to me all
the time. Should last forever.
Any drawbacks anyone can think of? Is this stuff particularly flamable,
so not suitable?
I could also apply foam board to the outside of the sheetrock (garage
side) and cover that with plywood, but with that air space between the
studs, I'm not sure this would do any good.
If I can get even r-10 or so, I'll be happy.
Any advice would be much appreciated.
If your idea really worked well, don't you think they would do it
Unless the packing material is certified for construction use, it is
likely to be against your local building code and a hazard if you have a
There is a right way and wrong way for every job. I think you found
The do, sort of. But only modified grade material is used. Bloc Fil in
Portland CT is one company that I know of that does this. The material is
ground finer that the packing material so it will flow better. The packing
material is shaped so that it will hold something in place in a carton and
thus, it will not flow into a cavity as well as a more granular shape.
Why not just cut out the sheetrock on the garage side, insulate with fiberglass
batts and then replace the sheetrock, tape & mud? It won't matter much what the
garage wall ends up looking like.
building codes usually require gypsum board on walls between an attached
garage and a living area due to the fire resistant qualities of gypsum
board; thus, the plywood and foamboard on the garage side would be violative
likewise, the popcorn packing material you mention is probably combustible
and would be violative (it may even light with a match and stay lit, worse
than being just combustible)
the least expensive and best bets are probably:
1. blowing (fire retardant) cellulose into the wall
2. or removing the drywall (may be easier from garage side) and installing
fiberglass (bats, etc.) within the wall; recommend you ensure there are no
air leaks leading to either the inside or the garage anywhere in the wall if
fiberglass is used, including around electrical wall outlets, noting
fiberglass is carcinogenic and cellulose isn't
with either one you should be able to easily attain the r-10 insulation
factor you desire
a vapor barrier might also supplement the insulating qualities of your
walls, and can be achieved to some degree with vapor barrier paints; not
knowing all of the variables at play here can't suggest or not suggest
additional coats of paint on the walls in your application (usually
recommended against in hot humid areas and recommended everywhere else)
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