The 2018 IECC includes a section (Chapter 5, Existing Buildings) clarifying that it is intended to apply to additions and major renovations in addition to newly constructed dwellings. Pennsylvania has adopted this chapter in its entirety with one exception:
Pennsylvania Rules and Regulations specifiy that the following sections from the 2015 IECC be used instead of the sections with the same numbers in the 2018 IECC:
This change eliminates duct leakage limits on these projects. Additions must still be tested, but there are no limits. Duct testing is not required on alterations (neither is blower door testing).
Editorial Comment:
The 2015/2018 IECC requires testing to verify that envelope air leakage fall below specified thresholds. This testing will be challenging to complete accurately when testing additions, where the leakage of the existing structure may affect the test results of the new components. Successful implementation of the new existing building requirements will require a degree of cooperation and improvisation by builders, testing contractors, and code officials.
