Insulating a Foundation
Insulating a Foundation
(OP)
Some contractors have suggested or actually
adding styrofoam around and beneath a foundation
for insulation. From what I understand this is
considered a vapor barrier which causes condensation
to build up between the styrofoam and foundation
walls.
Over a period of time especially in colder
temperatures won't this damage the foundation?
I can just see a crack in the foundation and getting
some type of moisture within the crack and then
freezing. That crack might no become a hole or
even a larger crack. Any comments about this method?
adding styrofoam around and beneath a foundation
for insulation. From what I understand this is
considered a vapor barrier which causes condensation
to build up between the styrofoam and foundation
walls.
Over a period of time especially in colder
temperatures won't this damage the foundation?
I can just see a crack in the foundation and getting
some type of moisture within the crack and then
freezing. That crack might no become a hole or
even a larger crack. Any comments about this method?





RE: Insulating a Foundation
The use of Styrofoam for insulating foundations is actually quite common. Hopefully some others will give you some pointers on the "do's and don'ts" of this material. (My use of geofoam for insulation has been limited to insulating freezers in areas where the water table is pretty deep.)
Please see FAQ731-376 by VPL for tips on how to make the best use of Eng-Tips Fora.
RE: Insulating a Foundation
insulation is within the concrete.
This part I understand but when applying
vapor barriers they do not recommend applying
the vapor barrier to the exterior a building.
Thanks for the info though
RE: Insulating a Foundation
RE: Insulating a Foundation
and it is NOT recommended that you place a
vapor barrier or vapor retarder it most situations.
The ACI 302 committee only recommends a retarder of
0.25 mm thick to protect from moisture. There are
three sites below that will explain it in more
detail.
The last WEB site explains the Vapor retarder in
great depth.
http://www.doityourself.com/hvac/vaporbarriers.htm
http://www.handymanwire.com/articles/vaporbarrier.html
http://www.lafargecorp.com/ttt_vbvr.htm
RE: Insulating a Foundation
If the vapor barrier is between the insulation and the moist air, that's where it's supposed to be. 'Nuff said.
It may help to draw a diagram of the "cold air",insulation, vapor barrier, and "warm moist air".
There is plenty of dispute regarding the value of vapor barriers. Not as bad as politics or religion, but give it time.
RE: Insulating a Foundation