The Problem with Uninsulated Rim Joists in Vancouver, BC

One of the biggest problems with crawl spaces in Vancouver Island is that the vast majority of them lack rim joist insulation.

The rim joist is the edge of the floor framing system. It is the large beam that sits on top of the foundation wall and supports the floor structure. It is usually exposed to the outside air, and if the rim joist is not properly insulated, when the air outside is cold, so is the rim joist. The crawl space is usually warmer than the outside air, and relative humidity levels in that space are usually very high.

When warm, moist air from the crawl space meet the cold rim joist, condensation occurs. The wood then soaks up moisture and it is only a matter of time before mold starts to develop.

“Most homes in Vancouver Island are either uninsulated, or they have batts – that pink stuff—up in the joist cavity, and that doesn’t do anything to stop that moisture from wicking up and condensing on a cold surface.” – explains Chris.

“Fifteen percent of the homes we fix have some form of bad damage, and probably 25 percent of the homes we fix have elementary levels of rot happening at the rim joist because of this condensation.”

Don’t let your rim joist rot away. Call Island Basement Systems for a free crawl space repair estimate.