How to Install Molding Around a Doorway
Update your home by installing new casing around your interior doors.
With a rag, wipe the wood with wood conditioner, stain and polyurethane sealer, letting each coat dry before starting on the next layer. Alternatively, apply primer, allow it to dry, and paint the trim in your chosen color.
Use a tape measure to measure the area around the door (Image 1). Then, use a miter saw to cut the trim to those measurements, factoring in a 1/8" reveal on the doorway (Image 2). Cut the ends at 45-degree angles to fit around the door jamb.
Lay the trim on the floor in the shape of the door; apply wood glue to the cut side of the trim and fit the two sides together.
Drill a small pilot hole through the top of the trim (Image 1); sink a screw into the pilot hole. Then, use a finish nail gun to drive a finish nail into the opposite corner (Image 2). Nail the rest of the trim into place (Image 3).