Easy DIY Picture Frame Molding (Box Trim)

Hi friends! Today I’m excited to walk you through how I added easy DIY picture frame molding (also known as box trim) in our living room. This was my first time installing wall molding, and first time using a brad nailer. If I can do it, you can too! This project can be completed without a miter saw which makes it more accessible for new DIYers. I’ll do my best to include all of the details in this post, but if you have any questions, please leave me a comment below or message me on Instagram! Let’s get started.

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Picture Frame Molding Supplies

Here are the supplies and tools you will need to complete this project:

1. PVC composite ply cap molding
2. Miter shears (or box saw)
3. 18-gauge brad nailer and brad nails
4. Tape measure
5. Painters tape
6. Laser level and tripod (or a basic level)
7. Caulk and caulking gun
8. Angle brush and wall paint

Easy DIY Picture Frame Molding Installation

Now let’s get into the step by step process for installing picture frame molding / box trim.

1. Plan and Measure Wall Molding Layout

This step may seem intimidating, but I promise it is easier than it seems! In terms of design, there are so many styles and designs for picture frame molding. For example, the boxes do not need to be the same widths, and you can stack as many boxes as you would like vertically. I would say the only “rule” is to use consistent spacing. Since this was my first time installing wall trim, I decided to keep it simple with three boxes following these rules:

• Vertical spacing: 3 inches between picture frame molding and crown molding / baseboard / top of media console
• Horizontal spacing: 4 inches between picture frame molding boxes and from the wall

In order to decide how wide to make each box, I taped out rectangles on the wall with painter’s tape to help visualize my design. I ultimately decided to make the center box the exact width of the media console, and the others would simply be based off of that following my rules listed above. I would recommend drawing a basic plan of your molding design and labeling it with the following measurements:

• The full length and height of your wall (excluding baseboard / crown molding)
• The vertical and horizontal spacing between trim pieces
• The outer length of each trim piece*

*It is important to measure the outer lengths for your trim pieces. Remember that you will be cutting the corners at a 45 degree angle. The measurements of the outside of the box (the outer corners) are the ones to use. Double check your measurements based on the length and height of your wall, and you are ready to go!

2. Trim the Molding with Miter Shears

This handy tool made this project so much more accessible for me. Miter shears can be used to cut molding at a variety of angles–no miter saw required! I decided to use PVC molding which is very easy to cut with miter shears. Alternatively, you can use wooden molding and a box saw.

Trimming the molding to size is simple:

• Mark the predetermined outer length of each piece of molding
• Adjust the miter shears to 45 degrees
• Line up the molding and cut slowly

3. Level and Tape Molding to the Wall

Once your molding is cut to size, it is time to level. You can use a basic level, but I decided to use a laser level and tripod in order to make things a bit easier.

• Use a measuring tape and pencil to mark where the outer corners of your boxes should be
• Align the laser level so that it is easy to place the molding
• Tape molding to the wall

4. Secure Molding With Brad Nailer

I’m not going to give specific instructions on using a brad nailer as this will depend on the tool that you have. Always read the warnings and follow all safety precautions when using power tools!

Here are some tips for wall molding installation using a brad nailer:

• Start near the end of the piece of molding (for vertical pieces, start at the top)
• If you cannot hit a stud, slightly angle your brad nails in alternating directions
• Do not nail the corners until you ensure that they line up
• Rely on the laser level so that the molding does not become bent or misaligned

5. Caulk and Paint

The final step! Put on your favorite audiobook or podcast and start caulking around the molding. This was my first time using a caulking gun and it was easier than I expected.

• Create a line of caulk along the edge of the molding
• Using a finger or a baby wipe, wipe off the excess
• Also caulk the corners of the boxes and any obvious nail holes

After your caulk has dried, use an angled paintbrush to paint the wall molding to match your wall. The trim almost perfectly matched my wall color to begin with, but I finished it with two light coats of paint. Our living room is Behr Marquee Cameo White (eggshell finish). And with that, this project is finished!

Easy DIY Picture Frame Molding in Our Living Room

I could not be happier with how our living room has come together slowly but surely. From the very beginning of this refresh last fall, to updating the furniture this spring, to the completed space with the wall molding, this space has come a long way. And it truly has been a labor of love! I hope you found this post helpful if you would like to add picture frame molding to your home, and please feel free to ask any questions you may have below!

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