Integrated Builders, construction management and contracting firm, has completed a $4.5 million rebuild of the former J. H. Emerson Co. factory into a sustainable, 16-unit condominium complex named Emerson Lofts.  

The 114-year-old property at 22 Cottage Park Ave. in Cambridge has been LEED certified. Integrated Builders worked with O’Sullivan Architects to overcome the challenge of maintaining the historic features of the building while improving its energy efficiency.

"Integrated Builders worked diligently preserving the original character of the building," Brad Spencer, the property’s owner, said in a statement. "The team was able to incorporate our desire for sustainable designs yet maintain the historic integrity of the building and neighborhood."

Integrated Builders restored and reused 95 percent of the building’s existing brick and timber structure. The historic factory originally developed and manufactured the first iron lung medical device, which acted as a precursor for the famous biotech and medical innovations that now take place in Cambridge. The reuse project included the overhaul of all mechanical and utility systems, a new elevator, noise and weather insulation and updates of all corridors and public spaces to be handicap-accessible. A TPO white roof, energy efficient HVAC systems and double hung insulated glass windows were also added.