Fairfax County officials have turned their attention to preserving affordability in high-rise buildings, a growing concern in a county that has become progressively more expensive and urban.

Officials do not expect to mandate developers to build affordable units into highrises, said Lee Rau, chairman of the Fairfax County High Rise Affordability Panel, which was created to examine the issue and recommend new policy. Instead, the panel is advocating creating incentives for a developer to do so, allowing more regular units to be built into a highrise in exchange for keeping some of the dwellings below market-rate and offering them to mid-income families.