Conflicting guidance on crawlspace rim joist details in mixed humid climates?
![](https://secure.gravatar.com/avatar/e7486f40976c8f71a7fc60e12d56afa8?s=52&d=https%3A%2F%2Fimages.greenbuildingadvisor.com%2Fapp%2Favatars%2F200x200%2Fb.png&r=g)
I keep going around in circles on this one because so many folks in the building industry here in central North Carolina have different opinions on how to insulate the rim joist in a sealed crawl space. It is very difficult to separate the “that’s how I have always done it and it works” methods from the science based best practices methods.
Doing research online does not seem to add much clarity as I see the same range of suggestions and they are often at odds with each other.
I see online at the US Energy Star page that several of their documents recommend using unfaced, batt insulation at the rim joist as shown here: Basement & Crawlspace Air Sealing and Insulating Project | ENERGY STAR
Martin Holiday’s article here from Fine Homebuilding says to never use batt insulation; but maybe his article is for vented, unconditioned crawlspaces? Insulating Rim Joists – Fine Homebuilding
So, what should I do to minimize condensation risk on my new construction home with regard to my rimjoists, in my sealed crawlspace? Ideally I want the rim joist to dry in and out just like the rest of my walls. It is very important for it to be able to dry in where the concrete porches are since that area has imperiable flashing on the exterior to separate the concrete from the house.
Thanks!
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