Similarly, the adaptation of existing structures may bring problems of their own, including the constraints imposed by historic preservation and environmental concerns. It is often asserted that the ability to use existing infrastructure is an advantage. However, in some cases the existing infrastructure is not adequate. In many inner-city neighborhoods existing infrastructure needs to be repaired, replaced, or modernized to serve both new and existing development. If the developer is forced to pay for these upgrades, the project may not pencil out.
Regulatory burdens are high.
Infill tends to be more heavily regulated than new development in newly developing places. Sometimes infill requires rezoning. Building codes can be unrealistic for rehabilitation projects. Restrictions on use can limit the types of units that can be developed. Existing neighborhood groups can feel threatened by infill.