How To's - How to Install Crown Molding

How to Install Crown Molding

Crown molding looks beautiful and gives a room an elegant finish. Installing crown molding, however, has a reputation for being difficult. In this article, we will break down what you need to know and how to do it so you can give any room in your house a quick and simple upgrade.

What You Need to Know Before Installing Crown Molding

Here’s a list of considerations and terms you need to know to install crown molding.


- There are basically two types of crown molding: one-piece and three-piece. Three-piece is the simplest to install. It includes two rails with one sitting flush against the wall and the other against the ceiling. This makes securing them in place simpler, since you can drive nails or brads in as needed on the rails. The drawback of one-piece crown is that you have to drive nails directly onto the wall only where there’s a stud.


- Before buying all the materials, get some samples or scrap and test it first. What looks good in a picture might not work in your room. Expansive crown that extends five or more inches might be out of place in a room with a 7 ½ foot ceiling, for example.


- Installing crown molding requires time and patience. Making the right cuts is essential to a clean, finished look. Even professionals take time to get the cut just right.


- "Miter" refers to a non-90 degree angle cut.


- "Cope" or "coping" refers to a professional carpentry technique that involves sawing one piece of trim to the profile of another for a snug finish. To do this, you use a coping saw. Although a professional technique, it’s easy enough for a beginner to learn and do.


- For inside corners, the bottom is cut longer than the top.


- For outside corners, the top is cut longer than the bottom.


- Try to buy pieces long enough to cover all spans of the wall. Otherwise, you’ll need to “scarf” pieces together.


- "Scarfing" refers to making a 22 ½ degree cut on the pieces of molding where you will need to join them when one piece doesn’t cover the entire span.


- If you don’t want to miter or cope, you can always buy and use corner blocks.


- Before you decide on the wood, first determine where it will go. Crown molding in a bathroom or kitchen must be real wood and not MDF board, as humidity will cause MDF to warp.


- Will you paint or stain? If you will stain, carefully select wood for similar tone and grain.

Tools Needed to Install Crown Molding

You don’t need a lot of tools for crown molding installation. Here’s a list of what you want to have ready to use for the most efficient installation.


  • (2) Step ladders
  • Tape measure
  • Stud finder
  • Chalk line
  • Pencil
  • Miter saw
  • Coping saw
  • Hammer, or brad nailer
  • Caulk gun
  • Safety glasses

A couple of notes on tools and materials:


- You can use a hammer and finishing nails to secure the crown molding in place, but construction adhesive applied to the back of the molding or wall and ceiling rails in a three-part crown and secured with brads until it dries will give it a more professional look. This approach reduces the size and number of nail holes you’ll need to fill.


- You will use the caulk gun to apply construction adhesive as you put up the crown molding. You’ll apply paintable caulk to touch-up inside corners once all the molding is in place.


- Two ladders are recommended to save time moving a ladder around the room every time you need to check a measure along a wall.

How to Install Crown Molding

Whether you install a one-piece or three-piece crown molding, the process is effectively the same. The three-piece will require a little more time, but it will likely mean fewer headaches.


Step 1. Mark the walls for the bottom edge of the molding. It may be easier to measure and snap a chalk line. Some professionals recommend putting up painters tape to protect the finish on the walls, so you don’t have to do touch-ups later.


If you will be using three-piece, mark the ceiling as well.


Using a stud finder, mark the location of all the studs. Use chalk for easier clean-up.


Step 2. Cut the first piece. For this piece, your cut will be 90 degrees on both ends. This piece should be the longest wall with two inside corners. By starting here, you begin with a piece that does not require a miter cut or a coped edge. Cut the piece to fit snug. Better to cut it long and trim it to perfection than cut it too short. Secure with nails or brads on the studs.


For a three-piece install, you will go around the wall installing all wall and ceiling rails first. Lightly apply adhesive to the back of these prior to securing in place. 


Step 3. Move around the room in one direction. This should make it simple as each piece will have a straight edge and one coped edge. In a rectangular room, the last piece always has two coped edges.


Measure the next piece. The side that will abut the first piece on an inside corner will have a coped edge. The other side should have a straight edge (for an inside corner) or need a 45-degree miter cut for an outside corner.


Notes on cutting a piece of crown molding:


- The top edge rests against the saw table and the bottom against the side fence.


- It’s best to make cuts with the miter saw cutting to the left of the table. This makes it easier to secure the molding in place and keep it steady for the cut.


- Draw a slash on the molding you are about to cut to indicate the direction of the cut, so you don’t accidentally cut it the wrong way.


How to Cut a Coped Edge:


- Cut a 45-degree miter cut on the edge you will cope.

- With a coping saw, make relief cuts at intervals along the edge. This will allow wood to fall away, making the cut easier.

- Cut along the edge at a 45-degree angle with the coping saw. Take it slow so you don’t splinter the wood.

- If needed, lightly sand the edge once you’re done.


Step 4. Slide the coped edge against the first piece of molding. If it fits snug, make sure it fits along the length of the wall. If not, sand or cut the coped edge to remove whatever excess remains. Trim the 90-degree or miter cut edge if the piece is too long. Secure in place.


This same process goes for the installation of a three-piece crown. But first you would do this with the wall rail and the ceiling rail. Once these are installed, then you would start with the middle piece of the crown molding, moving around the room in the same direction. The middle piece gets nailed to the wall and ceiling rail.


Step 5. Repeat for all inside corners as you go around the room. One edge should be 90 degrees with the other coped.


For outside corners, make a 45-degree miter cut on two pieces of scrap and test in the corner. If the angle isn’t right, adjust your cut until the two pieces fit as snug as possible. (The corners may look like 90-degree angles, but they rarely are.)


It is possible to have a piece with a coped edge on one side and an outer corner on the other.


Step 6. If you have any pieces that don’t cover the entire span of the wall, you will need to scarf the edge. In cases like this, it’s easiest to cope the smaller piece, so the longer one sits flush with a 90-degree cut in the one corner and the 22 ½ degree cut on the other edge.


Step 7. Finish work. Lightly apply caulk to any inside corners with gaps. Smooth the edge or close a gap on an outside corner by using the edge of a utility knife handle on the corner, applying pressure and gently rubbing it smooth. This pushes the wood in and covers the gap.

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