The Mystic River Apartments is a 10 building 240 unit housing authority complex located in Somerville, MA. The project included the addition of 240 pre-cast modular kitchen and bathroom structures to the exterior of the existing buildings, converting the flat brick buildings into a multi-dimensional complex. The modular units were erected in alignment with the existing kitchen and bathrooms that were demolished and converted into additional living space for the tenants. The integration of the structures included new foundations, new entrance stairs and canopies, renovated interior spaces, utility upgrades, new roofs and a pre-cast concrete parapet around the entire perimeter of the roof enhancing the overall look of the building.Boston Building & Bridge Corp. performed the work on an occupied site in (5) phases. Once each building was completed the tenants were moved in and the vacated buildings were renovated. The Somerville Housing Authority’s project is considered the pilot program for future state subsidized housing modernizations.