We'd like to make very clear it is important to seal the rim joist in your basement and crawlspace. Spray foam insulation will work better than fiberglass insulation because it will provide an air seal which is half the battle in these areas. When the rim joist has been framed out balloon style it causes a direct firewall all the way from the basement to the attic with no stoppage. This means air can travel up the wall and into the outlets and trim work. Unconditioned outdoor air often enters through the rim joist into the basement.
We can slow down air travel in these areas. By having an energy evaluation done, these areas can be properly tested for air leakage rates. Your energy auditor should conduct a blower door air leakage test, which will tell us a before and after air leakage number. This is done to log our improvement. This number is calculated in cubic feet of air per minute.
Please contact Green Home Logic today in West Hempstead, NY . We serve Long Island, Brooklyn, and Queens. We are happy to provide insulation and air sealing services to any 1-4 unit house or building. Please contact us today at www.greenhomelogic.com