This house was so leaky that before any air sealing and insulation, the blower door could not be operated to reach 50 pascal pressure difference, which is the standard to measure air leakage. Tom and his team took a series of steps. Using the blower door along the way to measure the result of each step helped identify problems and make corrections. Here is a summary.
- Installed liner in basement and crawlspace, air sealed hatch and basement door. Result: 6350 CFM (cubic feet per minute) at 50 pascal (result was interpreted from 44 pascal reading).
- Installed insulation, replaced with high performance triple-pane windows, installed SIGA housewrap. Result: reached 50 pascal when operating the blower door, 3063 CFM with basement door open; 2689 CFM with basement door closed.
- Applied sprayed foam to rim joist. Result: 2268 CFM with basement door open.
- Fixed missed spots in crawlspace. Result: 2064 CFM with basement door closed.
- Applied elastomeric sealant to perimeter floor-wall intersection. Result: 2095 CFM with basement door open; 1740 CFM with basement door closed.
- Installed blown-in cellulose in 2nd floor attic on the north side. Result: 1835 CFM with basement door open; 1385 CFM with basement door closed.
Tom is still looking for holes and cracks to fill up. We’ll publish the final results when it is all done.
Tell us: What are your preferred air sealing materials?
I really like the listing of steps and the corresponding drop in airflow during airsealing.