The Mallett House is a two-story wood-framed house located in downtown Freeport, ME and is one of several worker cottages built in 1886 for employees of the local shoe factory. It is currently used as a community center and office space. BSC guided the design team in the deep energy retrofit of the house, carefully assessing the existing condition to determine which retrofitting approaches were appropriate and what, if any, additional measures were needed to preserve the durability of the individual components of the building.
Retrofitting strategies adopted at the Mallett House included the use of two layers of two-inch foil-faced polyisocyanurate insulating sheathing on the roof and most exterior walls, blown cellulose insulation in the rafter and stud bays, a fully-adhered air barrier membrane installed over the existing board sheathing, spray foam and cellulose in the basement wall assembly, a new insulated basement slab, and new high-performance insulating windows. Per negotiations with the local historical society, the front facade was insulated from the interior to preserve the exterior detail. After completing the retrofit, the building was tested for airtightness and measured 0.68 ACH 50, exceeding expectations and impressive even for high performance new construction.