- Repair and preserve the original trim and decorative elements, even if worn or damaged.
- Replace with a replication only if damaged beyond repair or the material is unsound.
- Missing decorative details may be added when there is evidence that they existed. Evidence can be found from old photographs, remnants left on the building, paint lines where parts were removed, nail holes, old notches, and cut-outs in the siding and trim.
- Observation of details on similar historic buildings can assist but is not always conclusive.
- Do not fabricate a history that does not exist by using ornamentation that is foreign to a building or has no evidence of having existed.
- Decorative elements should not be removed simply because they are not original to the house. They may have significance of their own or as evidence of the evolution of the building.
- Decorative details should not be added to parts of a building which never had such details. For example, window and door trim was sometimes different and simpler on one side, both sides or the rear of the house.