BET provided building enclosure design and construction administration services for the complete renovation of 122 Commonwealth Avenue located in the historic Back Bay of Boston. The building was converted into three luxury residential condominium units. The project required full interior demolition and reconstruction, including the addition of an elevator, ground level interior parking, and an expanded 4th floor living space addition. BET assisted in the design of the of the exterior wall assemblies, including insulation, air/vapor barrier, and reflashing all of the window and door openings. BET also provided design services for the replacement of the main roof and terrace roofs, the replacement of the windows and doors, the installation of the basement waterproofing and insulation assemblies, and the restoration of the existing brick masonry walls. The penthouse unit included a fourth floor terrace with expanded living space, two large pyramid skylights, and a rooftop wood deck. The construction started in 2019 and was completed in the fall of 2020.