Installing door frame trim

Redo the cut until the header fits in place. Part 3. Position the trim against the wall. Place the pieces without attaching them to double-check the fit. Pay attention to how the header piece fits on top of the side pieces. Make any adjustments needed by further cutting down the size of the trim. Nail the side trim in place. Use a finish nailer to secure the trim. On the inside part, which covers the door jamb, use 4d or 1. On the outside part, which attaches to the wall, use 6d or 2 in 5.

Depending on the thickness of your trim, you may need larger nails. Hold the nails up to the trim to see if they're long enough to go all the way through to the wall. Drill and nail the header in place. Stand on a stepstool to reach the top part of the door. When finished, attach it the same way you did the other pieces. Push the trim pieces together to tighten them a little more. Measure about 1 in 2.

Measure down the side pieces and drill a hole through each from the outside edge. Nail the trim pieces in place. Stick 3d or 1. Start on one side of the door. When finished, move on to the other side. Caulk the holes, joints, and edges of the trim.

Spread it using a putty knife or your fingers. Then go around the outside of the trim, squeezing a small bead of caulk between the trim and the wall. Run your finger along the bead of caulk to smooth it out, then wipe it clean on a wet rag. Check the label information to find out how long this takes. Sand, prime, and paint the door frame. Sand the door frame lightly to make it smooth and even.

You can further customize your trim by staining or painting it. The trim can be colored with primer and a layer of paint. The quarter-inch of extra space is necessary to give the door hinges room to operate. Homeowners can create more elaborate door frames by adding multiple pieces of trim above the original casing board.

The general rule of thumb with built-up head casing is to add progressively wider trim as you go upward on the wall. Virtually any trim can be layered to create the look you want; consider using chair rail, bed molding, or concave cove molding.

Professional finish carpenters often use crown molding at the very top of a built-up head casing for a uniquely ornate look. Disclosure: BobVila. This is done with molding called casing. Casing can be molded or flat, and whether the casing legs and head meet at the top of the door in miter joints or butt joints depends partly on which you choose. For casing to sit flat and for the head joint to meet well, the jamb and the face of the wall need to be in plane with each other.

This is most important at the top of the door where the joints are. Check this by holding a straightedge on the face of the wall and extending it to the jamb—it should just kiss the edge. If the jamb projects slightly from the wall you can plane it flush.

If the trim is to be painted you can leave the jamb alone. These shims will keep the nails from pulling the casing back at an angle. To trace, use the molding as your guide. Molding is cut on degree angles to fit together seamlessly at the corners. With imprecise doorjambs, perfect miters produce less-than-perfect results. Measure and cut the top or header molding first. Align it with the reveal mark over the door, but check it with a level before fastening it down.

Use one nail at each end and leave the nail heads slightly raised. Predrill finishing nail holes to avoid splitting the trim, or use a pneumatic nailer.