Originally built in the 1860s Fletcher Hall was renovated in 2010-2011 into 5 faculty apartments inside 8700 sf. Envelope commissioning included a blower door and pressurized fog evaluation of the existing conditions, envelope design review, a quality assurance milestone test during construction and a final test near the end of construction. The challenge on this building was that the renovation scope included only selective demolition so new envelope components had to be fully integrated with existing envelope components to form a continuous air, vapor, and thermal barrier. In addition, the air barrier standard had to be set with an understanding that some areas would not be accessible for improvement. In the end the building improved air tightness by 47% and exceeded its air tightness target by 22%.