The Zoning Board of Appeal on Tuesday approved plans by the Louis D. Brown Peace Institute for a three-story Center of Healing, Teaching, and Learning on what are now two city-owned vacant lots at 30 Westville St.

Clementina Chéry started the institute after the death of her son, Louis D. Brown, gunned down in the crossfire of a gang shootout in broad daylight on Geneva Avenue 31 years ago - with the goal of providing help and healing for people affected by "murder, trauma, grief and loss" in Boston.

The new site is designed to lead visitors through a "pathway of decompression" from Westville Street into the 20,000-square-foot, three-story building, which will feature meeting and meditation and healing spaces, classrooms, offices and an auditorium, according to its plans.

Cyrus Dahmubed, architectural consultant on the project, told the board the building was designed to fit onto the L-shaped lot so as to preserve mature trees towards the rear as "a healing garden."

The building is designed to be a green structure and will include rooftop solar panels, along with high-performance windows and recycled construction materials to reduce its overall carbon emissions.

The project, which will take roughly 17 months to complete, will cost an estimated $13.4 million.

At the hearing, the mayor's office and City Councillor Brian Worrell (Dorchester) supported the project. Nobody spoke against.