Expert: Dave Johnson - 11/7/2007

Question
Does it pay to insulate the cinder block foundation in my basement (15 by 30 feet), where the furnace is located.  The cinder block foundation is about 5-6 feet under ground and 1 to 2 feet above ground. Because the garage is adjacent to the basement, one long wall (30 feet) divides the garage from the basement. There are two dry wells in the cinder block. Is there any quantification of the savings to be expected?

Answer
Hi Dick,
Insulating any foundation wall especially a block wall is
a little dicey. Right now there is some heat going into the blocks and keeping the frost from moving/cracking them.
If you insulate the interior that will stop this from happening and add to your chances of frost problems.
Ideally, the exterior should be done by excavating to at least the frost line and covering the blocks up to your wood walls with at least 1 1/2" of foam board. (this should be covered with a parge of "Top and bond" or similar product.
Best of luck, dave
AND if you need more help...mail me.