How To Install Crown Molding

Even experienced carpenters occasionally blanch at the prospect of a major crown molding job, and it isn’t hard to understand why. With plenty of acute angles, miters, scarf joints and irregularities, installing crown molding can be a demanding task. Even if your expertise runs deep, this is a physically trying job that requires working over your head for hours at a stretch. If you have patience, precision, and a proper work space, however, you can indeed install crown molding on your own without mortgaging your sanity in the process.

Before you begin, it’s important to think which style best suits the room. There was a time when most crown molding came in simple elegant curves, but today more hardware stores and specialty shops offer a variety of shapes and styles. Many homeowners imagine that more detail equals greater refinement, but in fact simpler geometries may be more appropriate for certain types of architecture. Brighter colors in particular work better with more basic shapes, though the saturated hues of Craftsman homes often demand more ornate cornices for balance.

The most essential part of the process is planning exactly which pieces will go where, and in what order. As you make your way around the room, cut each piece with a straight edge on one side, and with the other mitered or coped. This gradient around the circumference spares you the extra effort of cutting each edge to a precise form, and allows you to attach everything far more quickly. You may have to make additional plans for unusually long walls, as most prefab crown molding tops out at around 18 feet in length. Scarf joints are especially recommended where two pieces fuse, ideally over a joist in the wall to help keep them aligned.

Once you have the plan, you will need to cut the mitered joints that create a seamless flow from one piece to the next. Experience counts here, as you will essentially trace one edge of the crown molding that is already set to the appropriate offset angle from the wall with a saw to reveal the correct miter. Leave plenty of extra length, as mistakes are common at the beginning! Fit the pieces together inside a framing square to check your work. It’s not unusual to make several small adjustments until the fit is accurate. If they still won’t fit properly up on the wall, you may want accurately measuring the angle created by the molding’s two beveled edges before trying again.

Once all your pieces are ready, you can attach them to the walls and ceiling. Although many people recommend looking for joists as fastening points, you can usually get a far more secure fit by running a filler strip all the way around the room. This should be attached to the top plate, offering strength and consistency that will not warp over time. Nailing the crown molding to this material also saves you the trouble of searching for studs every few inches, and helps protect against the mold and mildew risks associated with sealed, empty spaces.

Countless other problem-skills may be required as you work, especially if the room has uneven walls, a curving ceiling or an unusual shape that requires certain sections to stop before they reach corners. You will have to make a return using the same coping methods as before for such truncated lengths, and may need to add additional wood pieces above the line of the molding and square off the ceiling using a scriber. The nails themselves must be countersunk and filled with wood putty, a process that demands its own patience and artistry. Finally, glue and sandpaper are typically necessary to make a seamless line out of any scarf joints.

The good news is that much of this work gets easier as you go along. Give yourself a comfortable and well-lit work space, with a surface to stand on near the ceiling, and have a friend hold up the pieces while you get the placement down. Most experienced carpenters simply go in order, but for DIY-ers it’s often recommended to save the most visible joints for last. By then you’ll be an old pro.

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