Foundation Insulation Panels

Last year, a trip to Menards revealed a new product - rigid foam insulation panels 1.5 inches thick, in precut sizes 2 feet x 4 feet. Okay, not such a novel thing right? Well the neat part was that one side of the foam board has a pre-applied adhesive and stone granules had been fused into it, giving a nice finished look similar to stucco. Hey wait, Humphrey House is half stucco! How perfect.

This is exactly the thing that we needed to help make the finished part of our basement much more comfortable. I purchased enough of these to line the sides of our house, and started off this summer by applying this to the below-grade exposed foundation wall we have from the basement's exterior entrance. When you think about it, an exposed concrete foundation wall is like a big heat sink exposed to the elements - it sucks the heat right of the adjacent finished space.

The panels aren't the prettiest when assembled in this fashion over a large space, since they are only 2 feet by 4 feet. I needed several panels and some odd sized ones which led to some ugly gaps. I tried to solve this by caulking the seams and then applying some extra granules, but it just didn't look right, so instead I ended up using some of our leftover stucco paint and applied it to give it a uniform look. Not the best work I've done, but at least it was passable for a rear basement entrance. It can always be re-stuccoed if the quality ever really gets to me.

After doing the entrance, I wanted to keep the basement warmer in winter, so when we got a brief warm spell in December (long after all the landscaping was dead or dormant), I got some help to basically dig a trench on the outside of the house beside the foundation wall so the panels could be installed 2 feet down. Since our basement is partially above grade, and partially below, this means that about 80% of the wall surface area is insulated. Even better, by having these panels on the outside rather than insulating from the inside, there is less "thermal bridging" heat loss. For those interested in infrared and building science and want to learn more, check this out, or look at these in-depth resources.

Anyway, we did this installation during the winter months while plants were still dormant so there would be less trampling and damage to what little landscaping we have along the sides of our home. The panels were installed in early January, and made a pretty noticeable difference as the finished basement is no longer nearly as cold as it used to be, which makes sense. If you house loses heat at the same rate (heat moves from warm to cold), if your entire house is insulated everywhere except the basement, your heating dollars are going to heat the Earth as much if not more than your home.

After the project was completed, we started to have spring come and you can see things are blooming despite the fact that there was a lot of traffic and digging overwinter.


The only thing left will be to take some of the remnant pieces and scrape of the sand which I will again attempt to caulk into the seams to make everything appear continuous. In the meantime, we're enjoying a much more comfortable and cozy basement!