WHYY By Homes across from Fairmount Park at 33rd and Clifford streets included in a new Strawberry Mansion Neighborhood Conservation Overlay District. (Kimberly Paynter/WHYY) (Kimberly Paynter/WHYY) These days, everyone wants to talk to Tonetta Graham about overlays — a zoning tool that can be used to shape development in a specific area. What would normally pass for municipal minutiae is a hot topic because Graham’s Strawberry Mansion Community Development Corporation and a coalition of other neighborhood groups recently won City Council approval for a special overlay district that aims to slow gentrification by restricting the height and density of new construction. Graham and her colleagues proposed the “Strawberry Mansion Neighborhood Conservation Overlay District” late last year after watching blocks of brick rowhouses begin to change with construction that they felt clashed with the historic fabric of the community. Roof decks are banned in the new district, along with certain popular facade wrappers such as vinyl, stucco and horizontal aluminum.