What Are the Different Types of Interior Door Moldings?

Classic Shapes and Designs

• Homeowners use classic architectural shapes and designs for doorway molding. For example, backband is building up molding to create extra depth. Keystone molding is decorative pieces used in the center at the top of the doorway. A shell corner is molding with rounded edges applied to corner blocks. A cap molding is a decorative piece used to top a molding build-up, similar to a hardware finial.

Casing

• The casing is the flat piece of wood that frames the door opening. A standard casing is 3 to 4 inches wide on the door's vertical sides, and 3 to 4 inches tall on the top of the doorway opening. The casing forms the foundation for layering the doorway treatment with trim or molding, or it can be left plain and painted. In most cases, the corners of the casing are mitered at a 45 degree angle.

Base Blocks

• A base block is a square or rectangular molding piece placed at the doorway's base. These blocks are traditionally thicker than the casing and the depth of the baseboard next to the door. The end of the casing rests on the top of the base block. The block can be decorative or left plain.

Corner Blocks

• A corner block is the upper equivalent of a base block, placed on the left and right sides of the casing. These blocks are typically square shaped and decorative. When corner blocks are used, they are the last piece added, and placed on top of other trims and molding materials so they stand out. Corner blocks are sometimes used to eliminate the need for mitering the upper edges of door casings.

Build-Up

• Build-up is the term used to describe using multiple molding pieces. Build-ups add depth, texture and originality to doorways. For example, a homeowner might select three or more pieces to use to decorate and trim the doorway. They combine different shapes, widths and styles of molding. One piece might have a rounded shape and another might have a decorative pattern such as a leaf or indentations.

Architrave

• An architrave is a decorative molding that is positioned at the top of the doorway. This type looks like miniature versions of a fireplace mantle. They are ornate and include a build-up of various molding materials to create the mantle effect. For example, an architrave might include one or two round moldings and a piece in a dentil molding style with a repetitive carved square pattern. The left and right sides of an architrave molding piece typically flare outward from the top of the doorway at a 45 degree angle.