XPS vs professional spray foam for basement rim joists
![](https://secure.gravatar.com/avatar/0de5b40d5229899807192f263948cbbb?s=52&d=https%3A%2F%2Fimages.greenbuildingadvisor.com%2Fapp%2Favatars%2F200x200%2Fp.png&r=g)
I live in SE Michigan and recently had an energy audit done on our home we purchased 6 months ago; And have since discovered a whole bunch of issues.
The house was built in 1978 with a poured concrete foundation, and the rim joists were insulated with paper backer fiberglass insulation. After removing several of the panels mold and moisture were discovered 🙁
My question is: is there a difference in performance between DIY XPS/great stuff vs professional installed spray foam? We are trying to keep costs down and I am an average DIY’er
And second, should the joists be given time to dry out longer then when moisture is visible?
Thanks!
Patrick
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
![](https://www.greenbuildingadvisor.com/app/themes/greenbuildingadvisor/dist/img/modules/detail-library/thumb1.png)
![](https://www.greenbuildingadvisor.com/app/themes/greenbuildingadvisor/dist/img/modules/detail-library/thumb2.png)
Replies
Patrick,
1. It's best if you can wait for weather conditions to change, and for the rim joist to dry out, before you insulate the rim joists.
2. A do-it-yourself job with rigid foam can be just as effective as a spray foam job. But the quality of the job depends (in either case) on the conscientiousness of the installer.
Here are links to two articles you may want to read:
Insulating rim joists
Basement Insulation — Part 2