Door casing is the trim installed around a door frame that covers gaps, enhances appearance, and provides a finished look.

Door casing is the decorative and functional trim installed around the perimeter of a door opening where the door frame meets the wall. Its primary purpose is to conceal gaps between the jamb and wall surface, creating a clean, finished transition while also enhancing the overall design of the space.

In construction, door casing is typically installed after the door frame and drywall are in place and before final painting or finishing. It can be made from a variety of materials including wood, MDF, PVC, or composite products, with profiles ranging from simple flat stock to ornate, traditional moldings.

Beyond aesthetics, door casing also helps protect wall edges from wear and minor impacts near door openings. Proper sizing, alignment, and fastening are important to ensure consistent reveals and long-term durability. In both residential and commercial projects, door casing style is often selected to match baseboards, window trim, and overall architectural design.

In historic buildings, door casing profiles were often used to signal the importance of a room—the more ornate the casing, the higher the room’s status.

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