Infill development involves building new residential structures within existing neighborhoods and town centers on vacant/underutilized lots or inside existing buildings. Such lots and buildings are often non-compliant with current standards. Municipalities can have a process that relaxes dimensional and density standards in zoning codes for housing that is at least partly affordable. In less dense, rural areas adaptive reuse of  pre-existing larger buildings, such as  barns and commercial structures,  can be allowed to  convert these to residential uses even if multi-units are not typically allowed in the district .