How to Do Door Casing: Step-by-Step Guide for Perfect Installation

Achieving a professional finish starts with proper door casing installation—this small detail elevates your door’s appearance and protects the edge from wear.

How to Measure and Cut Door Casing

Begin by measuring the interior perimeter where the door meets the frame. Use a tape measure to record width and height, then cut the casing using a miter saw or jigsaw. Always cut at a 45-degree angle for seamless corners, ensuring a tight fit without gaps. Sand rough edges to prevent splinters and ensure smooth installation.

Preparing the Surface and Applying Finish

Clean the frame surface with a damp cloth to remove dust and debris. Apply a coat of primer if the casing is painted, enhancing adhesion and color consistency. Use a high-quality finish—such as water-based latex or oil-based polyurethane—applying thin, even coats. Allow each layer to dry fully before sanding lightly and applying the next, achieving a smooth, durable surface.

Installing and Securing the Casing

Position the cut casing flush against the door frame, aligning edges precisely. Use thin finishing nails or specialized casing nails, driven at a 45-degree angle for secure hold. Work from the center outward, tapping gently to settle the pieces. Check alignment frequently with a level to ensure straightness and symmetry.