What should you do with your basement? Well, air sealing is the most important thing to do! The rim joist is the vertical board that sits on top of your foundation. It leaks air. If you have insulation there and it is dirty, it has been filtering the dirt out of the air leaking through it. Sealing any holes in the basement ceiling such as chimneys, plumbing stacks, electric lines, plumbing lines, and duct work is important. We can insulate the rim joist and the walls in your basement.