Want to give a room the ultimate finishing touch? Crown molding, which bridges the corner where walls and ceiling meet, is a designer upgrade that works with most decorating schemes, from traditional to contemporary. There are plenty of styles to choose from, and with our quick how-to, you can install it yourself.

Remember: Wear proper safety gear, including eye and ear protection, when working with power tools.

Step 1: Rough-Cut Molding

Rough-cut molding at least 2 inches longer than needed. On pieces that will need to be spliced (see Step 11), allow an extra 6 inches.

Step 2: Sand, Prime and Paint Molding

If the molding you purchased is bare wood, sand with 100-grit sandpaper and wipe off dust with a tack cloth. Prime with ZINSSER Bulls Eye 1-2-3 Primer. It covers stains and marks, seals and provides a smooth surface for paint. Mildew and mold resistant, it dries in one hour. When the primer is dry, lightly sand with 180-grit sandpaper. Wipe off with tack cloth and apply the first coat of paint.

Step 3: Locate and Mark Studs

Use a stud finder and mark stud locations on the walls and the ceiling with a carpenter’s pencil or, if you don’t want to put marks on the surfaces, a small piece of painter’s tape. You’ll use construction adhesive and a brad nail gun to attach the molding to the wall and, when you can, to ceiling joists.

Step 4: Make Gauge and Mark Placement

Mark where to position the molding on the walls and ceiling with the help of an L-shaped gauge you make from scrap wood. To determine the size of your gauge, place a piece of the molding in the corner of a carpenter’s square and note the measurements of the molding’s run (across the ceiling) and drop (down the wall). Cut the scrap wood and nail together. Mark the location of the crown molding on the ceiling and walls using the gauge.

Step 5: Plan the Installation

When learning how to install crown molding by yourself, it all comes down to sequence: Start with the longest wall, then move to the right. That way, you’ll make the most of setting your saw for 45-degree cuts to the left. And the motor will be out of the way, making it easier to hold the molding and see your cut marks. At inside corners, a coped end fits over a square-cut end. In rectangular rooms, the

 last piece often needs to be coped on both ends. Outside corners are mitered. (For how to install crown molding corners, see Steps 9 and 10.)

Step 6: Cut the First Piece

Measure the length of the first (and longest) piece of molding, using the marks on the wall for molding placement. Unless your walls are exceptionally long, you should be able to use a single piece of molding. Square-cut both ends by laying the molding flat on the miter saw.

BONUS TIP: For the most accurate measurements, use a two-step technique: First, measure from a corner and make a mark. Then measure from the other corner to the mark, and add the two measurements together.

Step 7: Attach Molding

Apply Dynagrip Heavy Duty Construction Adhesive to the back side of the crown molding as needed before attaching. This formula’s powerful instant grab will hold molding, making it easier to nail it in place as needed with brads. Use a brad nail gun and 1½-inch brad nails at the studs and joists. If there are no joists to attach it to at the ceiling, drive nails in about every foot or so at a 45-degree angle. With a damp cloth, wipe away any adhesive that may squeeze out.

Step 8: Prep the Miter Saw

Set up your saw for miter cuts: To make miter cuts for coped joints and outside corners, you have to lean the crown molding—tilted at the correct angle—against the saw’s fence. Pencil lines on the saw’s bed or fence can help you position the crown, but a little extra saw setup can help even more. Fence extensions and stop blocks, for example, make positioning fast and foolproof. If your fence doesn’t already have holes that let you screw on extensions, you can drill holes. Or you can fasten the extensions with hot-melt glue and pry them off later. Besides providing a taller fence if needed, the extensions let you screw on stop blocks.

Step 9: Make Coped Joints

To make coped joints on inside corners, mark the direction of the cut with a slash mark. Set the molding upside down on the saw and cut a 45-degree angle. Then clamp down the piece and use a coping saw to follow along the line defined by the molding profile and the 45-degree cut you just made. As you cut, tip the saw at an angle, to create a back bevel. Fine-tune the cut with a rasp. Then nail it in place.

BONUS TIP: If the coping saw blade tends to slide to one side as you start a cut, make a small starter notch with a utility knife. Make sure the teeth in your coping saw point toward the handle. That way, the blade will cut smoothly on the pull stroke. Just be sure not to force the saw forward. Make even strokes, applying only light pressure, and let the blade advance at its own pace.

Step 10: Make Mitered Joints

To make mitered joints on outside corners, place the molding upside down on the saw. Cut each piece about 1/16-inch beyond the length marked. On pieces of scrap molding, make 45- degree cuts and test the fit on the corner. If the corner isn’t quite square, try again making 46- degree cuts and tweak them until you get a tight fit. Finally, nail it in place.

Step 11: Make Scarf Joints

On long walls, you may need to splice two pieces of molding with a scarf joint. Cut the molding so the shorter piece will overlap the longer piece and the joint will be over a stud. Place the first piece of the molding upside down on the saw. Make a 45-degree cut on the right end (where it will be joined with the other piece of molding). Turn the blade 45 degrees to the left. Put the second piece of molding upside down on the saw and make a 45-degree cut. When installing the two pieces, attach the longer piece first.

Step 12: Fill Brad Nail Holes

Brad nails should be below the surface of the molding. If any of them aren’t, you need to countersink them: Carefully hammer the brad nail until it’s nearly flush with the baseboard. Then place a nail set on the top of the brad nail and tap with a hammer to push the brad below the surface. Fill all brad nail holes with Plastic Wood All Purpose Wood Filler, a latex- based product. It creates a surface and body that looks and acts like real wood but is low in odor and cleans easily with water. Don’t overspread the filler but do slightly overfill the holes. Let it dry, then sand it flush with 100-grit sandpaper.

Step 13: Seal Gaps and Cracks

Seal gaps and cracks—where the molding meets wall and ceiling, and at joints—with Alex Flex Premium Molding & Trim Sealant. Cut the tube’s nozzle at a 45-degree angle at the bead size required. Fill the gaps with sealant. Use a finishing tool to smooth the sealant. It will be ready for latex or oil-based paint in just 30 minutes.

Step 14: Paint the Molding

Give the molding a final coat of paint.