Somerville Mayor Joseph Curtatone has thrown his support behind a proposal to convert the former Powder House Community School into a 40-unit housing complex with 13,000 square feet of commercial space.

The project would be led by MarKaLLC, an affiliate of Somerville-based Sebastian Mariscal Studio, one of eight developers that responded to a request for proposals early this year. Elements would include eight live-work artist units offered at below-market rates, 12 senior citizen units and 20 loft-style apartments.

The commercial space would consist of three retail spaces, two service-oriented units, a restaurant space, five collaborative workspaces and one artists’ hall, according to a press release.

MarKaLLC submitted a $2.8 million cash offer to buy the 2-acre property on Broadway. The 80,857-square-foot K-8 school was built in 1973 and was closed by the city in 2004 due to declining enrollment.

MarKaLCC said its partners include Parts and Crafts, sprout & co. affiliate STEAM (science, technology, engineering, arts and math) Academy, the Collaborative Living Project and the Somerville Bicycle Academy.

Tufts University was selected as the preferred developer in a previous round of proposals, but the two sides ended negotiations in 2014 in a disagreement over the timetable.

The project needs final approval from the board of aldermen and negotiation of a final disposition agreement.