This 106,000 square foot 4-1/2 story historic brick masonry building was built around 1890 as a mill owned by the W.H. Hill Envelope Co. It has been partially vacant for several years and is now being rehabilitated as 64 energy efficient apartment units. BSC is providing building enclosure and air barrier/compartmentalization consulting for the project. Noting that there was some evidence of freeze-thaw brick damage, BSC provided construction details that will minimize water penetration at the roof edge, windows, and proposed canopy attachment. BSC developed a strategy for air sealing at the exterior and demising walls, wall/roof and wall/floor intersections, and plumbing penetrations and shafts in order to meet the airtightness goals of the project. The details to implement these strategies were incorporated into the architect’s plans. BSC provided recommended details for retrofit insulation of the exterior walls, with specific details around windows and at the wood beam pockets at the exterior masonry walls.