The Boston Planning & Development Agency board recently approved a three-story, 21-unit rental residential building for Stedman Street. The project will consist of six one-bedroom units and 15 two-bedroom units, and four of the 21 units will be income-restricted.The income-restricted units are expected to be one one-bedroom and three two-bedrooms, said BPDA spokesperson Bonnie McGilpin. One of the affordable units will be for a household not earning more than 30 percent of the area median income (AMI) as dictated by the U.S. Department of Housing and Urban Development (HUD). One unit will be for households not earning more than 50 percent of the AMI and two will be affordable to households not earning more than 70 percent of the AMI. Sited at 50 Stedman St., the building will be approximately 31,216 sq.