MassDevelopment has issued a $3.2 million bond on behalf of St. Joseph Hall Apartments LLC, which will help fund the acquisition and renovation of St. Joseph Hall in Watertown.

All units in the 25-unit, senior housing facility are affordable to households earning up to 60 percent of the area median income. This acquisition will ensure the units remain affordable in perpetuity.

Metro West Collaborative Development, a nonprofit based in Watertown, is the project sponsor. Renovations include exterior masonry and stone repairs; basement waterproofing; and replacing windows, kitchen cabinets, flooring and interior walls. Watertown Savings Bank purchased the bond.

In addition to the bond, MassDevelopment assisted the Department of Housing and Community Development with the approval of federal low-income housing tax credits, which provided approximately $1.4 million in equity for the project.

Built in 1935 by the Dominican Sisters of Peace, St. Joseph Hall housed the Rosary Academy High School until the school closed in 1981. In 1988, the building was renovated to create 25 apartments for seniors – 22 one-bedroom units and three two-bedroom units – and the Education Francaise Greater Boston, a private preschool for about 30 children.