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Pete C. Pete C. is offline
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Default Blown in cellulose in new construction


HeyBub wrote:

ls02 wrote:
I am thinking about using blown in cellulose insulation for new
construction: walls, attic as well in floors between first and second
floor and between first floor and basement. I have a lot of pipes and
wires so I suspect blown in cellulose will provide better value then
fiberglass batts which hard to put around so many obstacles.

Has anyone done this?

What's the cost of blown in cellulose vs fiber glass batts?

What's the best way to apply it to walls and floors? I saw video when
they blow it to wall open cavity then use some sort of screed to
screed excess flush with walls. What about floors? If I blow it to
ceiling will it stick and not fall down?


Not cellulose. The stuff you see squirted into an open wall is polystyrene
foam (think Great Stuff).

Sprayed foam has superb insulating qualities (R=6+/inch) and not cheap.
Fiberglass is about 2/3rds (R=4/inch) the insulating qualities of foam.
Cellulose has about the same R-value as fiberglass, but is typically applied
in a thinner layer resulting in an overall lesser R-value than fiberglass.

You can't easily use blown-in cellulose on a wall. To do so, you have to
finish the wall, open a hole, fill the cavity, then patch the hole. One hole
per stud. After that, the cellulose will settle with time and you'll end up
with only 3/4 of the wall insulated.

In your case, I'd recommend fiberglass batts and a sharp knife to mold it
around pipes and wires.


Actually, they do indeed do cellulose based blow in insulation in open
wall cavities and screed off the excess flush with the studs. The
cellulose is I think lightly dampened for application and I suspect has
some light tack binder added. At any rate from what I've seen it works
well and should be much easier to fish wires through later if needed
than the spray foam or fiberglass batt insulation. For new construction
I still recommend installing strategically placed conduit since 3/4" PVC
conduit is very inexpensive and installing it in new construction will
take all of one evening and cost $20 or so.