City officials on Thursday approved developers’ plans for a pair of commercial-to-residential conversions, including a 21-unit apartment complex in Jamaica Plain and a 13-unit condo complex in South Boston.

Developer Joseph Hanley of Quincy-based RPT Washington St. LLC obtained Boston Redevelopment Authority approval to redevelop a restaurant building at 3383-3389 Washington St. in Jamaica Plain as a $3.5-million apartment and retail complex. The plans by Studio47 Architects call for 21 apartments, including four fourth-floor penthouses with dedicated roof terraces. The 27,633-square-foot complex also will include 2,300 square feet of ground-floor retail, 23 parking spaces and a fitness center.

Also at Thursday’s meeting, the BRA board approved the conversion of a gas station property at 57 L St. in South Boston into a 13-unit condo building by Moawed Properties LLC.

The $7.1-million project designed by Roche Christopher Architects calls for construction of a 20,130-square-foot five-story building and 21 off-street parking spaces in a ground-level garage.