Crawl Space Insulation

Denver Crawl Space Insulation

A common question from Denver homeowners…

Do I Need Insulation in my Crawl Space?

The 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. 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.

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.

Rim Joists

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 shows how Casey installs crawl space insulation in a Denver home


There Are 2 Applications


R19 ramset to the foundation




Can’t get wet, hard to maneuver in tight spaces, lots of labor to install.

Spray Foam

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.

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We are here to answer any questions about spray foam insulation

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