Ever wonder what to do about that empty space between the top of your cabinets and the ceiling? Want to have a custom-looking cabinet? Then let’s close off that space and trim it out to give you some height and a more finished-looking cabinet. This is an easy Diy kitchen cabinet project!

You can watch a quick TikTok on how we closed the gap on our Diy kitchen cabinets!
Here is the list of what you will need to complete this project!
Materials List:
2 x 1 lumber (supports)
MDF
Base trim molding (chair rail)
Upper trim molding (crown)
Caulking & wood filler
Nail gun – 16Gauge
Miter saw
Circular saw and cutting guide
Coping saw for crown molding
Step 1. – Measure and planning
First you’ll need to figure out how much of a gap between the top of the cabinets and the ceiling you are going to board up, as well as the total length of too. These measurements will be needed to figure out how much MDF to buy / cut as well as the amount of trim moldings needed to tie everything in.
In my case, I had an 18 inch gap to cover and one run was 14 feet while the other side was just a touch over 9 feet. The MDF I used was 1/2″ thick and comes in 4 x 8 foot sheets. So I could only get three 18 inch strips cut out of one sheet for a total of 24 feet so I needed to get two sheets and I would be left with extra, which I’m going to use in another DIY soon.
For the trim, I used a chair rail to cover the seam between the existing cabinets and the new wood. I chose this one because of the width was not too small and the design was simple enough. Chair rail link
For the upper trim, I knew I was going to use crown molding and I also wanted to do something a little custom. So I choose to combine a few different moldings together to come up with the profile I went with. This is called “built-up crown” and the options here are totally up to you and your can come up with a truly unique look pretty easily.
Upper trim link – 3 pieces
Crown trim link – 3 pieces
Drop trim link – 4 pieces
For a great article on how to cut and install crown molding, please check this link out. I used most of the tips and it really was pretty easy once you know what tools to use and how to setup the cutting jigs.
Step 2. Bracing
Now the initial build starts. Take the old upper trim off the cabinets and begin to attach blocks and supports to the top of cabinets. These braces should be about 24 inches to give you a nice sturdy point to attach the MDF to as well as give the MDF some sturdiness.
I would also make sure to add a block to the bottom as well to give you that extra anchor point for the upper brace. The blocks are 3 inch long and 2 inch wide. The upper brace is 18 inch tall and 2 inch wide. Your length will vary.
Now that the braces are in place, time to cut the MDF into 18 inch strips. Your local home depot / Lowe’s will do this for you if you don’t have a circular saw with a guide or table saw. Then I nailed the MDF to each support. To help with this, just make a pencil mark on the ceiling where the supports are so you know where to nail. That will be covered up by the trim later.
Step 3. Lower trim
Now it’s time to add the “base” trim / chair rail to tie the new wood with the cabinet. This is pretty straight forward. Measure the lengths you need and cut. For anything longer than a 12ft run, make a 60 degree cut on that end and on the next piece to seam or scarf the pieces together (see the article referenced above).
Step 4. Upper trim
This part can get a little tricky. If your are using a single piece of crown then you won’t need build out the trim like I did which will save time. But I wanted something unique and the trim components are readily available so when I go to add the crown to the rest of the house I can just buy more and start cutting. So first attached the upper trim, to get the look I wanted I had to space it 1/2″ off the MDF. From there I build a mockup of the crown moudling (see article) to be able to get the “drop” distance and cut 1/2″ off that drop to get the mark for the drop trim to attach. Then it was time to attach the crown. See this picture to see how the “build out” of the trim is going.

The corner above is basically how you are going to “cut” the corners for all of your crown. One piece will not have a cut and the other piece will have the 45 degree cut and using the coping saw, the extra wood behind will be removed so it fits tight to the other piece. I will refer you to this article again for more details and photos of the technique. It totally works and after you get your cutting jigs made, doing more crown will be easy.
Step 5. Fill and prep for paint
Fill all the nail holes with wood filler, let dry and sand smooth (150 or 180 grit works great). Caulk all the seams between the MDF and trims as well as the cabinet, ceiling and wall seams.

After all the caulking has dried, all the seams are smooth and nail holes patched, it is time to start to paint. We used our trusty Snowbound paint color (Sherman Williams). There were a few touch ups but overall I am pretty happy with the finished look.
The finished design! We love it!

What under mount lights did you use? I want to add lights under my cabinet and want to know a good option
This was the kit I used that I purchased from Amazon. https://www.amazon.com/gp/product/B07WK9C35N/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1
Hope this helps.