I am going to show you how I added box molding to a barrel arch. A barrel arch is an archway that extends further than a typical doorway. If the arch encompasses a large part of the ceiling or an entire hallway we would call it a barrel ceiling.
We have one barrel arch in our entire house and it happens to be the entrance to our bathroom from our bedroom.
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Because of the flood the first 2 feet up from the floor of the wall was removed in this barrel arch. It left us wondering how we would restore the arch. When they removed the drywall, they also removed the metal bullnose edging.
Least to say we were left with quite the mess to fix. I do not like bullnose corners. I saw this as a great opportunity to hide the bullnose corners and add some wall paneling into our barrel arch.
Tools and supplies I use to trim a barrel archway and barrel ceiling
- 1×8 – at least 4′ long
- 1×4 enough for 8 verticals, and boxes and ceiling trim
- Sharp pencil
- String that doesn’t stretch
- Level
- Table saw
- Finish nailer
- 1 3/4″ brad nails
- Measuring tape
- Wood filler
- Flexible putty knife
- Sander and sand paper
- Miter Saw
Smooth out the ceiling and walls of the barrel arch
You first want to create smooth walls. Ours have an orange peel texture. After the flood I skim coated all of our bedroom and closet walls with drywall mud to remove any texture. I have a great highlight on Instagram sharing my skim coating tips.
It’s the only way I know how to finish drywall. It’s also my favorite wall finish.
If you do not know how to skim coat or want a quicker way you can use a combination of masonite/tempered panel board or 1/4″ plywood for the sides and bendy board for the barrel arch ceiling.
I didn't use the bendy board for our barrel arch, but I did use it for all of the other arch doorways.
Trim the outside edges of the barrel arch ceiling
To make the trim for the outside edges of the barrel arch ceiling I had to cut a 1×4 board that I could bend. But, before that I needed to know how long the board I was about to cut needed to be.
String theory
I took a piece of string, placed it on the corner of the arch and pressed along the entire length of the curve. Once I got to the next corner I cut the string. I measured that with a measuring tape and cut my board 2″ longer to be safe. I cut two boards, one for each side of the arch.
Kerfing the board makes it bendy
Kerfing is what it’s called when you make a series of cuts along a board, perpendicular to its length. These cuts are relief cuts, they remove meat from the board and allow it to bend at each cut. The deeper the cut, the easier it bends, but also makes it more fragile.
I found leaving 1/8-3/16″ of meat – or in other words – removing just under 5/8″ from a 3/4″ board was just the right amount of bend without breaking.
I raised the blade on my table saw to remove just under 5/8″ from the board.
Once the blade is at the right height, I set my table saw sled up to make perpendicular cuts.
Then I removed the fence, placed my board on the sled and ran the board across the blade, pulled it back, and then moved the board about a 1/4″ or so over for the next cut. I wasn’t very exact I just used a mark on my table saw to align the last cut on.
I continued this for both boards making relief cuts along the entire length. These are the boards that would be placed on the ceiling of the barrel arch on the outer edge.
Find the angle
I kerfed the boards and now they can bend. In order to nail them in place I needed to cut the ends in a miter cut that matches the angle of the arch.
Place the angle finder inside the corner. My angle is 65 degrees. Because this angle will be made from two pieces of trim joining each other, I divide 65 by 2. I get 32.5. This is the cut angle I need to make on both ends of the boards in order for them to join properly.
Remember that angle, it will come in handy later.
Cut your trim boards and attach them
I placed my kerfed boards just on the outside of the doorway. I bent it along the curve and marked where I needed to make my cuts so that it would fit into the arch. I placed my board on my miter saw and cut the board to make an inside joint at 32.5 degrees on either side.
Then I measured and cut the 1×4 vertical trim pieces for the arch.
I nailed the vertical boards first, making sure they were level. Then, I nailed my curved board in place between the two vertical boards. Repeat on the other side.
The curved board gets nailed so that the finished and uncut side is the side you see and the cuts are placed against the ceiling or the curve of the arch. Once it’s nailed in place I like to fill it with nail filler. Once the filler is dry, sand it smooth to the touch.
Mine looks a little jagged because I added caulk over my filler, then removed the face trim to adjust it and it pulled the caulk away a bit. Yours won’ t look like this.
If you are hiding a bullnose like mine, pull your boards out and over the bullnose edge so that when the face of the trim is attached it will square up the edges.
Trim the outside arch door casing
If you would like to know how I added trim to the door way casing arch I wrote an entire blog post and tutorial about that here: how to trim an archway. Do this next that way if you have to make any adjustments to the inside vertical trim or curve trim you can before you go too far.
Create your box moulding in your barrel arch
Measure the distance between the two curved boards, mine was 24″. Cut 4 – 1×4 boards per side: two at the top and two on the inside. I also cut a 1×8 for the base 24″ to fit between the two vertical ends.
Nail the base in place first.
I set my table saw to make a cut 32.5 degrees. Set your saw to whatever degrees you measured previously.
I ripped the two top boards along one edge to create a long miter joint. I nailed these in place – one on the ceiling of the barrel arch and the other on the wall where it meets the ceiling barrel arch.
Then, I measured the distance between the top wall trim and the top of the base wall trim. It was 84″. I wanted 3 boxes so I divided 84″ by 3 and got 28″. This means that the center of each board will be 28″ away from each other to get three equal sized boxes.
I nailed my last two 24″ long pieces 28″ on center from each other.
This post is one of an 8 week series of posts part of the Fall 2022 One Room Challenge. We chose our bedroom ensuite in order to get one large area of the house done since the flood we had in January.
If you would like to read more about the challenge or see the incredible transformations being done by other guest designers, click here. If you liked this post you may like my post from the third week. It’s all my go to tips for installing baseboards. Or my post on installing wainscoting.
If you enjoy building stuff for your home, check out my nightstand plans, they’re easy to follow and look amazing when completed. Or if you love a good hack I converted my standard stainless steel dishwasher into a paneled dishwasher here!
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Disclaimer: Working with power tools and DIY projects can be dangerous and post inherent risks. While we work hard to ensure the accuracy and effectiveness of the tutorials along with the information displayed on this website, Hambels Get Real cannot be held responsible for damages or losses sustained or incurred in the course of your project or in the use of the item you create.
Apartment Therapy is the official media partner for the One Room Challenge and I am pretty excited about it because they do such a great job featuring small time and big time designers.
