[Greenbuilding] Exterior insulation retrofit
9watts at gmail.com
Thu Apr 28 08:19:15 PDT 2011
On Thu, Apr 28, 2011 at 5:45 AM, <bill.allen at verizon.net> wrote:
> While the siding is down, fill the wall cavities with cellulous from the
I did that and am very glad I did. Our consumption of firewood has dropped
by 45% per HDD relative to our starting point which was like yours: no
insulation. And that does not include the dramatic rise in temps (low and
high) achieved inside now that we have insulation in the 2x4 walls. Mesh
glued and stapled to the studs will work, but you'll want to take your time
getting everything to do with the mesh squared away before you blow. Having
it come loose is not what you want. Don't skimp on the staples. If you could
accommodate thin furring strips to hold down the mesh that would probably be
even better. Or are you thinking of adding plywood sheathing and drilling
holes? If you search the archives there are some great and very detailed
discussions of how to approach blowing dry cellulose into open wall cavities
from outside. If you have the right blower and are game you can also blow
the stuff wet.
> Replace original double hung windows with new construction insulated, R-5
> if we can afford it, windows mounted "innie" on the plane of the original
> dimensional 1x lumber t+g sheathing.
> Add external insulation....rigid styrofoam. Since there is no interior
> vapor barrier (plaster on wood lathe), I am worried about the dew point
> ending up in the center of the wall...therefore, per the building science
> article, add 4" of styrofoam to the outside to keep the dew point external
> of the sheathing.
> Will require careful details at windows and other penetrations.
> Big job...has anyone done this? Any comments on any part of the above
> would be most welcomed.
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