Crawl Space Insulation
Do I Need Insulation in my Crawl Space?
We get this question about crawl space insulation often and our answer is always yes.
Conventional wisdom suggests that insulating the ceiling of the crawlspace will make the floors above warmer in the Winter. This is not the case, and here is the science behind it.
Conditioned crawl space– First, the thermal barrier (insulation) shouldn’t be in direct contact with the crawlspace ceiling or the trusses of the floor above. The reason for this being; we want that crawl space ceiling to be warm so warm air must move through it. We want to block the cool air at the point of infiltration from outside (the concrete exterior walls), thus we’d like to move the thermal barrier (insulation) to the exterior concrete foundation walls. If done correctly, we can insulate from the wooden rim joists above the concrete walls down to the vapor barrier.
This is a reinforced poly plastic that is 6mil. We lay this seamless barrier over the exposed earth and tape it around all pylons, and footers so no water, vapor, or gasses can enter the home. If you have a musty or earthy smell in your home, a vapor barrier will solve this problem.
Above your crawlspace foundation walls, you’ll find the framing for the floor above. These trusses are supported by the rim joist that sits directly on top of the foundation. These wooden squares are usually 1 square foot each and 12-16” apart. We will foam these with 3” to stop cool air from infiltrating into the crawlspace above the foundation walls. These rim joists are a big reason why in floor insulation doesn’t work, it’s because the insulation is attacked from the side rendering the insulation useless because the air moves through the insulation that was hung in the ceiling trusses. Foam these and stop air infiltration.
This video will explain how insulation in your crawl space can save you money on your utility bills.
There are 2 Applications
R19 ramset to the foundation
Can’t get wet, hard to maneuver in tight spaces, lots of labor to install.
Low pressure closed cell 2 component spray foam.
It’s a vapor barrier itself so water doesn’t affect it, only need 2 guys to run it, guaranteed great install as the foam does all of the work.
Need to be out of the house for 2 hours after the install for vapors to clear out. More expensive than R19.