Old houses are tricky. While not ideal, an airtight layer can be established from the exterior.
A new method for air-sealing the shell
Tape is best, but the right caulk can also provide a tough, reliable seal
Use specialized tools and materials and a methodical approach.
In September 2009 I completed a deep energy retrofit on a small house in Point Reyes Station, Calif., some 50 miles north of San Francisco.
