3 Easy Steps to DIY Picture Frame Moulding Tutorial

March 9, 2023

Hi! I'm Nicole

Fearless DIY. Sharing building project tutorials and interior design tips. Let’s build something beautiful together. For more projects, design tips and behind the scenes, follow me @designtobuild.nicole

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What do you do with a long wall? Picture frame moulding is my new favorite go-to. And in my picture frame moulding tutorial, I’ll show you exactly how to do it.

We have a very big room down in our basement that has gone through a few transitions over the years. It started off as my older sons’ bedroom that they shared for several years.

When they both graduated, moved out and onto their own ventures, it became our tv room. Which was really just a room for our younger boys to hang out with friends, watch tv and play their game systems.

However, I always had a vision of something more for this room. As our family is growing (with grandchildren in the future), I wanted this room to be a place we all loved to hang out. And so, over the last few months, I have made that vision a reality. Our own home theater room. A place we all want to be! It’s the coolest room in the house!!

Picture frame moulding tutorial Header Image

Whether you call it picture frame moulding (or molding 🙂  ). Wainscoting, or box paneling. Shadow box molding or shadow box trim. It’s all the same. For simplicity sake, I’m going to call it picture frame moulding. But just keep in mind, you may hear this evergreen style called by other names.

Picture frame moulding is a beautiful and elegant way to add dimension and interest to your walls. Whether you’re looking to enhance the look of your home or simply add a unique touch to a specific room, this type of trim can help you achieve the look you desire.

In this picture frame molding tutorial, I will take you step-by-step through the process of installing shadow box trim, from measuring and cutting to attaching and finishing.

Whether you’re a seasoned DIY-er or just starting out, this guide will provide all the information you need to create a stunning and eye-catching wall feature in your home. So gather your tools and let’s get started on this beautiful and easy DIY picture frame moulding project.

How to Create a Wall with Picture Frame Moulding Tutorial

Materials Needed for Picture Frame Moulding Tutorial:

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(Amount of supplies needed is dependent on the project)

Tools Needed for Picture Frame Moulding:

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Step One: Measure

The very first step you’re going to want to do is measure the wall where your moulding is going to go. I chose to do one long wall, but picture molding would also look great done in an entire room.

Math has never been my strong suit. So, if I can do it, you can too!! Here’s how I did it:

How to measure picture frame moulding boxes:

  • Determine how many boxes you want
  • Determine the dimensions of each box
  • Measure the length of your wall
  • Measure the height of your wall
  • Add together the total width of the boxes
  • Subtract that total from the total length of the wall
  • This will tell you the distance each box needs to be from one another
  • Repeat these same steps to determine how far from ceiling and baseboard your boxes should be

Ok, that might be a bit confusing, so let’s work this out. Below is a diagram of my picture frame moulding tutorial:

My wall is super long. Coming in at 270 inches (22 1/2 feet).

After determining I wanted four boxes, I chose the dimensions I wanted each box to be: 38″ x 52″.

To determine the spacing needed between each box, here’s what I did: I multiplied the total length of each box. 38″ x 4 boxes. This gave me 152 inches. This number represents the amount of space my 4 boxes cover (lengthwise).

I then took my total wall length minus the length my 4 boxes take up. 270″ minus 152″. This gave me a difference of 23 1/2″. Therefore, I will need to space out my boxes 23 1/2 inches apart from one another. This will also be the distance from each wall corner to my first box.

See the diagram below for further clarification….

Picture frame moulding tutorial diagram

To determine the height spacing of my boxes, here’s how I did it:

I measured the height of my wall from the top of the baseboard to the ceiling. This wall is shorter in this room because of ductwork that runs along it. Therefore, the height of my wall from baseboard to ceiling is 79 1/2 inches.

I then subtract the height of my picture box from the total height of my wall. 79 1/2″ minus 52 1/4″. This gives me a difference of 27 1/4 inches. Divide this number by two. 27 1/4″ divided by 2 equals (approximately) 13 3/4″.

Therefore, I will measure up from my baseboard 13 3/4 inches and down from my ceiling 13 3/4 inches, to determine where my picture frame boxes will be installed.

Again, the diagram above draws this out for you. I’m definitely a more visual person, so I hope you find the picture frame moulding tutorial diagram helpful too. As always, let me know if you have any questions in the comments below.

With all of my measurements, I made pencil marks to make my markings. But, because my wall is so dark (Black Magic by Benjamin Moore), I decided to use painter’s tape to make it easier to see….

Shadow box moulding outlined with blue painters tape on a long black painted wall.

Step Two: Install picture frame moulding

I can not recommend highly enough purchasing a nail gun (or brad nailer) for this project. If you don’t already have one, this is a great option. I use my nail gun ALL THE TIME. So, it will definitely get used in future projects too. I can’t imagine doing this project without my nail gun. It is the real champion in this DIY project.

The first thing you’ll want to do is cut your trim. The tool you use, will depend on if you’re using real wood or PVC moulding. For PVC moulding, you can complete this project without the use of a miter saw. This tool will work great!

I chose to use real wood, as supplies were limited. Therefore, instead of making multiple trips upstairs and out to the garage, I chose to cut all of my left vertical pieces first….

A room with tape outlining a wall where trim is to go for my picture frame moulding tutorial

You’ll want to cut all of your boards at 45-degree angles, on both ends. Ensure that each angle is facing the right direction. Refer to picture below for clarity….

One trim piece attached for picture frame moulding tutorial

Using a level, attach each of your vertical boards with your nail gun. It is helpful to nail in the middle first. You can then move the board to make it level, without having to fight with gravity…

Picture frame moulding tutorial with painter's tape outlining where trim is to go.

Once all of my left boards were in place, I chose to place my bottom piece next. Once again, I cut all of these horizontal pieces at the same time. Once again, paying attention to the direction of each angle. And then, using my level, I attached this bottom board with my nail gun….

An L-shaped trim design on a black wall

Moving onto the top moulding trim piece, I made all of my cuts at the same time. (With attention to the direction of the angles). Brought them downstairs and began to attach each top piece with my nail gun…

Trim pieces attached to a black wall to form 3 sides of a rectangle

It is so important that you make sure every board is level, before attaching it…

A girl with a wool hat on holding a trim piece up to level it on a black wall.

Now, I was ready to place my last board in my picture frame moulding tutorial.

For my right side cuts, I made these individually. Since it was my last board to attach to complete the box, there wasn’t a lot of room for error. So, for each of these right piece boards, I made a separate trip upstairs and out to my shop to make the cuts. And again, for the last time, it’s important to pay attention to the direction the angles need to be cut….

A picture frame moulding tutorial box with trim in a rectangle pattern

In no time, I had all four picture frame moulding boxes finished. Don’t worry, if your trim pieces don’t line up perfectly together. That’s the beauty of wood filler and paint. We’ll get to that in the next step. But for now, step back and admire your work. Isn’t it lovely? Can’t you just envision it with a fresh coat of paint?? Ahhhh! So good!!

3 trim boxes on a black wall for a picture frame moulding tutorial blogpost

Step Three: Finish work

First up, you’ll want to fill in all of your nail holes with a little bit of wood filler.

Use that wood filler to fill in any of those gaps you may have between your trim pieces too. Anywhere your trim work didn’t line up perfectly. Wood filler is your friend; filling in all of those imperfections for you. I love that stuff!!

Once the wood filler is dry, you are ready for paint. When choosing a paint color, it’s best to paint your picture frame moulding the same color as your walls. The easiest way to paint your trim is with a paint brush, rather than a roller.

As I mentioned before, I chose this moody Black Magic by Benjamin Moore. It is the perfect color for a theater room. But it would also look great in an office, master bedroom, dining room…to name a few.

I highly recommend painting the ceiling too. Here’s a look at this room before I painted the ceiling. What an incredible difference painting the ceiling made for this space. The end result is stunning…

Media console with floor to ceiling bookshelves

Want to build these bookshelves? Here’s the link.

Want to build this media console? Here’s the link.

And that is literally all there is to it! Three simple steps to a beautiful feature wall. Now, you may be wondering, what’s next? Now that I have these picture frame moulding boxes, am I going to put anything inside them? The short answer–YES! I’ll be sharing a tutorial for how I made the abstract wall art for inside each of these boxes.

Honestly, you wouldn’t have to put anything inside of these boxes. They are beautiful all by themselves.

Sectional sofa with lots of pillows, soft blanket in front of picture frame moulding walls

But the textured wall art really does add to it. That contrast of black and white is, oh so good!!

Canvases hung on wall behind a sofa

Other Types of Accent Walls

Before we go, let’s talk real quick about some other fun accent wall ideas.

There are so many wall treatments to choose from. If you’ve been on my site long enough, you know that I am a huge fan of wall treatments. They can really take a boring wall from “blah” to “wow”. My favorite wall treatment are board and batten walls. This classical style is so easy to create and will really elevate any room.

Of course we have all heard of shiplap. Thank you Chip and Joanna. 🙂  And while I still love this design, my favorite way to install shiplap is the vertical shiplap technique. I have done this on my ceilings and my walls. What a statement vertical shiplap makes.

Recently, wood slat walls have been all the rage. This is another easy feature wall treatment. It can also be an easy way to bring natural wood into a room. Like I did here in my kitchen makeover.

Black kitchen island with a Golden Oak stained wood slat accent wall behind it

An accent wall in my home that really gets a lot of compliments, is my board and batten box wall. This wall is great for a staircase area or a wall with high ceilings. It definitely becomes a conversation piece. Not to mention, it’s a lot of fun to create.

It was so much fun to try my hand at this (new to me) accent wall treatment. I love how it turned out and am now looking for other walls I can add this feature to…

Wall of canvases

I hope you found this step-by-step tutorial for this picture frame moulding tutorial to not only be informative, but something you can easily re-create. It really is an easy DIY project. Follow these step-by-step instructions and make your own accent wall, that will have everyone asking, “Who did you hire to do that for you?” No one! I did it myself!!

Let’s go beyond the design to build something beautiful together!

Be sure to Pin This Post to your Pinterest Board for later…


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More Wall Treatment Projects:

How to Create a Mid Century Modern Accent Wall





How to DIY a Wood Planked Ceiling


The Easiest Way to Shiplap a Wall

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