2 Reasons to Air Seal a Rim Joist

If you are adding some improvements to your basement, then you may also want to air seal your rim joists. These are the outer joists which support the under-flooring, and because of their position, they are often more vulnerable to moisture, mold and other atmospheric problems that can affect the standard of your basement. Adding an air seal to a basement is a good way of ensuring that the wood remains solid.

1. Protecting Against Moisture

If you are trying to air seal your rim joists, then what you actually want to do is to protect it from moisture. Air carries droplets of water with it everywhere it goes, and this includes into wooden joists. Preventing air from moving around in the joists prevents water from building up there. Stopping air flow is also important if you want to heat the basement, as changes between hot and cold air can crack the joists.

2. Protecting Against Pests

Another problem with wooden joists is that they are vulnerable to plant and insect damage. Air sealing your rim joists will help to keep them from being attacked by mold, which could simply rot the wood. This type of protection can also limit the amount of damage from termites, wood beetles or wasps.