[Greenbuilding] [BULK] underfloor insulation R-values & materials

[Lawrence Lile]

Wet Spray cellulose is your friend.  Cheap, 100% recycled, always fills
up gaps and odd shapes unlike Batts, you can spray it upside down into
an overhead space (usually through a screen that looks like mosquito
net)  It will fill up any shape space, and it is better R value than
most of the alternatives.  The only thing better is biobased (made from
soybeans) foam, but the price is steep.  



 
Lawrence Lile, P.E., LEED AP
Senior Electrical Engineer
Project Solutions Engineering

-----Original Message-----
From: greenbuilding-bounces at listserv.repp.org
[mailto:greenbuilding-bounces at listserv.repp.org] On Behalf Of Reuben
Deumling
Sent: Tuesday, November 28, 2006 3:02 PM
To: Greenbuilder list
Subject: [BULK] [Greenbuilding] underfloor insulation R-values &
materials
Importance: Low

I have now used the Bonded Logic cotton batts a number of times and like
them fine for several reasons. What I don't like is that they only come
in
R-13 and R-19 strengths. My floor joists (the basement ceiling) are
2x8s. I
would like to utilize the full 7-1/2", especially since I've found the
cotton batts to tend toward the thin side of their rated thickness.
Another
complicating issue is that the bays vary in width from about 21" to 24".
I
also now own (thanks to this list) an insulation blower that will need
some
mechanical attention from me before I use it. Within a few years I
intend
also to insulate the day light portions of the basement walls, which
will
put the basement into a limbo category between conditioned and
unconditioned.

My questions are
(a) Is it worth pursuing insulation that is 2" thicker than R-19 in this
application? I hope to insulate the rest of the house a la Corwyn to
R-40 or
better, down the road.
(b) of the choices I've thought of (unfaced cotton R-19 batts,
fiberglass
batts?, wetspray cellulose?) are there obvious ones to prefer under
these
circumstances?

Thanks.

Reuben Deumling
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