How to Install Crown Moulding
Time Required: Over 1 day
Crown moulding, also known as ceiling trim, can transform the rooms of your home. This guide will teach you how to install crown moulding.
Several moulding profiles used together are called build-ups. These combinations may look complex, but they are installed basically the same way as regular crown moulding.
Outside corners are mitered, but inside corners should be coped. A coped joint is one in which one moulding is cut to nest against the profile of another. This helps to disguise out-of-square corners, wall irregularities and problems caused by wood expansion.
- Prime and paint (or stain and varnish) all sides of the moulding, including the back, before you install it. This will help keep it from warping, and ultimately save you time.
- Wear appropriate hearing and eye protection when cutting your moulding.
- Using a nail gun saves time and gets better results when hanging your crown moulding.
Tools & Materials
- Start on the wall opposite the door (wall 1 in diagram) and install a piece that’s square at both ends. This presents the best (and easiest to cut) side of the joint to anyone entering the room.
- The moulding on the second wall (2) is coped where it meets the installed moulding, and square where it meets the other wall.
- The third wall (3) is treated the same way, and the fourth wall (4) is coped at both ends.
- Put the moulding against a framing square noting the distance between the face of the moulding edge and the corner.
- Cut a scrap of lumber to the correct dimension and draw layout lines on the wall and ceiling.
- When you install the moulding, align it with the layout lines.
- Begin at the wall opposite the door and cut moulding to that length.
- Mark the locations of the studs by holding the moulding in place and transferring the marks onto the moulding.
- To prevent splitting, drill pilot holes the diameter of the finishing nails.
- Drill holes at each mark at the top and bottom of the moulding and nail in place.
- Lay out the cope joint on a second piece of moulding and start with a piece that’s a few inches longer than the finished length and flex it in place.
- At the end that you'll cope, draw a line in the general direction you'll cut at roughly a 45-degree angle.
- When first learning how to cut crown moulding, position the moulding so that the ceiling edge is flat on the bottom of the miter box and the wall edge is tight against the fence.
- Set the saw to cut at 45 degrees in the general direction of the line you drew in Step 5. (If the blade and line won't come close to aligning, turn the moulding upside down and try again.)
- Cut a miter close to the end.
- Look at the face of the moulding. The miter cut exposed the profile of the moulding, outlined in this picture in pencil. Cutting away the excess wood beneath the profile creates an outline that can nest against the adjacent moulding.
- Tilt the coping saw back at a 45-degree angle to create a razor-thin edge where the two mouldings will meet.
- Sand and file any high spots to create a tight fit.
- When the joint fits, measure the wall.
- Cut the moulding 1/8” longer than measured (usually by making a square cut on the uncoped end).
- Flex the moulding in place. The extra length will help push the cope joint closed.
- When the moulding fits together without any gaps, nail the moulding to the wall and ceiling.
- Putty the nail holes.
- If you're painting the moulding, run a bead of caulk in the seam and wipe it smooth with a wet finger.
Don't be afraid to try out different crown moulding ideas - use crown moulding to create a picture frame or border a built-in bookshelf.