Single doors hooked up by hinges to a frame, usually precut for hardware installation. A simple paint finish is a good way to add colour or charm to present or new interior doors. Homeowners most often paint their interior doors when hoping for a up to date feel or to higher match current trim or wall colours. Generally the least costly of the three supplies, hollow-core doors are constructed from a wood body, plywood or hardwood surface and full of inflexible cardboard to maintain their shape. While lighter and cheaper than stable wooden or strong-core doors, hole-core are not as durable or fire-resistant.