If you propose to make modifications to a property (structure and site included) that is designated as a local historic property you will need to follow the steps for obtaining a certificate of appropriateness (COA) prior to pulling necessary permits and beginning work. To determine whether the property is a locally designated historic property, follow the instructions here.
What is a Certificate of Appropriateness?
A Certificate of Appropriateness (COA) is an official document which certifies that any exterior changes to a property located in a local historic district or a property designated as a local historic landmark are in keeping with the design review criteria established for each district or landmark. This requirement applies to all properties located within a local historic district, regardless of age or significance, and to all local historic landmarks.
The requirement for a COA applies to all properties, regardless of age or significance, that are located in a designated local historic district or designated as local historic landmarks.
Any change to the exterior of a property or to a site requires a COA. This includes, but is not limited to:
Alterations and additions
Restoration of buildings, walls and fences
A COA is required regardless of whether the modification to the exterior or site is visible, and regardless of whether or not a building permit is required for the work.