How to Incorporate Crown Molding

A standard feature in older homes, crown molding can give new construction a sense of character—and it’s a big-reward project that you can tackle over the weekend.

Material options. Wood molding is a perennial favorite, says Matt Muenster, an interior designer and licensed contractor who’s the host of DIY Network’s BATHtastic! The more exotic the wood, the more expensive the molding will be. Pine and MDF (mediumdensity fiberboard) are the cheapest and most basic wood options, and they paint very well. Note that pine doesn’t stain evenly, so if you’ll be staining, opt for a hardwood like maple or oak. For a less expensive option, consider pressure-injected foam or plastic. “You can get pretty intricate detail out of cast molding,” says Muenster.

First step: Prep. “If your walls are in good enough condition to paint, they’re ready for molding,” Muenster says. Spackle and sand holes, wipe off dirt or stains, and touch up the paint before you start. If you’re planning to paint the room as part of the makeover, be sure to do that first (check out our experts’ color suggestions on page 34), since the molding will be placed on top of the color. If you use unfinished wood molding and plan to paint it, prime it before installing; if you plan to stain it, stain it first. Most foam and plastic versions come in standard white, so you won’t have to paint them.

How much to buy. Measure around your room to figure out how much to buy. Add 10 percent to that number if you’ll be mitering the corners. Most molding comes in 8- or 10-foot lengths, so divide the total measurement by that number to see how many lengths you’ll need. You’ll want to buy the largest lengths you can to minimize the joining and cutting you need to do, and always round up when it comes to your calculations.

Corner options. You have two options for corners: a corner block (a piece of molding angled to fit into a corner) or a mitered corner (cutting the molding at an angle). With a corner block, you’re only making straight cuts, so you don’t have to worry about mitering the joints. It’s easier, though it doesn’t always look as polished. “This is a good option if you don’t trust yourself to miter corners,” says Muenster. If you’re mitering, measure the angle of the corner first, then use a miter saw to dial in the right degree—ideally, all corners are a perfect 90 degrees, but sometimes they’re a degree or two off. Make sure you place the molding in the miter box correctly (it has to go in at the same 45-degree angle at which it will be installed). Always cut the left side first, then match up the pattern before you cut the right side.

Attaching to walls. Wood molding is best attached with nails directly into the wall studs. Use a stud finder to locate these spots, then mark them along the length of your molding; drill pilot holes in the molding before placing the piece on the wall. An alternative is to rent a pin nailer, which uses air pressure to drill headless trim nails into the molding. Another option is to use a construction adhesive (like Liquid Nails) to glue the molding in place. Adhesive is better for lighter molding (like foam or plastic) than heavier types.

Finishing up. Once your molding is in place, use paintable silicone caulk (like Krylon All Purpose Paintable Silicone) to smooth out the rough spots and fill in places where the molding isn’t perfectly flush with the wall. Use a lightweight spackle compound to cover up nail holes (that’s why you want to paint after installation), then paint the crown molding your desired color.