How to Cut and Install Crown Molding 

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Crown molding installation is a simple and cost-effective way of adding value and ambiance to your home. Besides, it forms an appealing transition between the ceiling and walls. Even better, you only need basic carpentry skills and a few tools to start learning how to cut and install crown molding.

installed crown molding

However, unlike other trims, installing crown molding can be a bit tricky. One reason for that is that the installation process involves cutting compound angles with a miter saw. More notably, the project is accompanied by various challenges and requires precise craftsmanship.

Don’t let that worry you though! In this guide, I’ll show you how to install crown molding step-by-step. Moreover, you can apply some of these skills in other millwork installation projects like baseboards, door trims, chair rails, etc.

First, here are the tools and materials you’ll need to undertake this project.

Tools & Materials needed

  • Fine-grit sanding sponge
  • Masking tape
  • Crown moulding (MDF/ Wood)
  • Power miter saw
  • Tape measure
  • Caulk gun
  • 2 6-ft. Stepladder
  • Paintable caulk
  • Paint primer
  • Glossy trim paint
  • Paintbrush
  • Pencil
  • Finishing nails & nail gun

Steps of installing crown Moulding

Step 1: Measure the walls

Using your tape measure, start by measuring the lengths of every wall in the room. This will help you determine the length of the crown molding profile you need for the project. More importantly, ensure you buy enough molding to cover the entire room, with some excess to account for waste due to fitting and cutting.

Step 2: Cut crown moulding

The first thing you need to note before you start cutting trims is that the crown sits on the wall at an angle. For that reason, it’s good to make your cuts at an angle instead of laying them flat on a miter saw. Also, you can either make a customized guide or buy a jig to help you make precise cuts. Better still, this will prevent the molding from slipping while cutting it.

Another great trick is to set your molding against the miter saw and use a pencil to make a line on the working table. This line will act as a visual reference, helping you make consistent cuts for all trims. In addition, set the saw at a 45 degree angle to match the direction of your molding.

That said, measure and mark the pieces of crown molding for cutting. Position it upside-down at a 45 deg angle on a miter saw table and make your cut. Here, you either use a power or a manual miter saw to cut the molding. However, I’d recommend that you stick to a power miter saw since it delivers more precise cuts.

Note, there are 2 types of corners you’ll come across when cutting crown moldings. That is; outside corners and inside corners. In essence, inside corners have concave, inward-facing 45-degree angles. While an outside corner has a 45-deg convex angle pointing outwards.

Another notable joint you’ll encounter when cutting crown molding is a scarf joint. That is because, in some instances, the moldings will not always cover the entire length of the walls. Thankfully, scarf joints allow you to join 2 straight pieces in an almost invisible way. Moreover, they provide a much more professional-looking result compared to joints with square cuts.

How to cut crown molding

  • Scarf joints

For walls that are longer than the lengths of your molding, you have to combine 2 pieces. And as I’ve already stated, the best way to accomplish that is by making scarf cuts. So, set your saw for a 45-deg cut depending on the direction of your crown molding installation around the room. Next, cut the 1st and the 2nd piece in a manner that allows them to overlap. After ensuring the pieces can fit together perfectly, joint them with wood glue before attaching them to the wall.

  • Inside corners

An inside corner features a single square-cut piece that touches the corner, while the other end is cut at an angle to fit against the 1st piece’s profile. To cut an inside corner, set your miter saw at an angle of 45 deg. If the joint is on the right side of the crown molding, place the molding to the left of the saw. Similarly, if the joint is on the left, put the molding to the right of the saw.

Also, make sure the molding is set into the saw at an upside-down position as cut it. In other words, place the bottom edge of the molding against the saw’s vertical fence. If done properly, the bottom edge should be longer than the top edge.

  • Outside corners

In most cases, outside corners are not perfectly square. Therefore, simply cutting both pieces at 45 deg doesn’t guarantee they’ll fit tight at the corner. For that reason, it’s important to determine the exact angle of your corners before you make the cut.

To accomplish that, you will need 2 wooden pieces of equal size. Hold those pieces against both sides of the wall, ensuring they overlap by 1”. Using your pencil, draw lines along the lower and upper overlapping edges of the wooden piece that flushes with the ceiling. Connect the opposite corner of these lines with another line. Stack the piece and use your miter saw to cut along that diagonal line. Now, use this angle to cut the outside corner of your molding.

Unlike inside corners, the bottom edge of an outside corner should be shorter than its top edge.

Step 3: Apply paint primer to the wood crown molding

If you’re planning to install wood molding in your home, it’s good to prime it before you install it. More importantly, let the primer paint dry before installing the molding. But, if you’re working with MDF molding, this step isn’t necessary since they’re already primed.

Step 4: Mark wall studs with a pencil

Crown molding is usually nailed to the ceiling joists and wall studs. Unfortunately, ceiling joists only run in one direction, meaning there are inadequate joists to attach along both surfaces. However, if your moldings are small enough, probably around 1.5- 3” wide, you’ll get a tight fit, just by nailing them to the wall studs or against the ceiling.

So, as you wait for the primer to dry, use this time to locate the wall studs or ceiling joists. Moreover, make sure you mark each stud with a pencil. Those marks will act as a guide while nailing up your pieces of crown molding against the wall surface.

Step 5: Crown molding installation

Before you attach the molding to the wall, remember to flip it over to ensure it is upright. Once you’ve done that, hold the molding against the ceiling and wall at a 45 degree angle. However, this angle may vary depending on the style of molding you’re using. Just make sure the angle formed by molding is precise.

Most crown moldings come with flat faces on the bottom and flat edges. More notably, these faces fit flush against the ceiling and wall.

Next, using a power nailer, 2 -2.5” finish nails or drive brads, attach the molding against the wall studs. If possible, set the nail gun in a manner that allows the nails to be countersunk. Repeat the above steps until all the crown molds are secured against the wall.

Step 6: Fill the gaps

For any corners that didn’t meet perfectly, fill the gaps with a bead of paintable caulk. Repeat the same process to fill any space or gaps where the crown molding meets the wall or ceiling. Also, use the caulk to fill any visible nail holes, then wipe the surface smooth using a damp rag.

Let the caulk dry, then lightly sand the surface with a fine-grit sanding sponge. Once the molding gets a nice, seamless look, go ahead and apply 2 coats of glossy paint.

Step 7: Paint the crown molding

After performing all the steps above, put the painter’s tape along the bottom and top of your moldings. Then apply the 1st coat of paint and let it dry as per the manufacturer’s specifications. If needed, apply the 2nd layer until the moldings are completely covered.


Although crown molding installation seems like a complex process, it’s relatively simple if you have the right tools and materials. And by following the steps I have listed above, the task will even become simpler. Alternatively, you can either hire a carpenter or contractor to install the moldings for you. All in all, if done right, crown moldings will certainly add a decorative architectural element to your home!

People Also Ask

Does crown molding installation require backer boards?

If you’re installing a larger crown molding, it’s important to install a backer board as well. That way, you’ll have a solid surface to nail the molding at various points along the wall.

What part of the crown molding should go up?

Although you can install crown molding upside down, it isn’t recommended. Instead, the rounded (convex) side should go up, while the cove (concave) side should go down.

What is the average cost of crown molding installation?

Installing crown molding costs about $567 – $1868. This brings the average crown molding cost to around $1217. So, expect to pay around $4- $15 /linear foot for both materials and labor. However, this price may go as high as $30 for metal and exotic hardwood moldings.

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