This is the start of a new series on the blog thanks to my new title as a homeowner (which is very exciting). My husband and I are excited to pursue several DIY projects – the first being some box molding (sometimes called picture frame molding). Considering this was our first foray into anything like this, I can tell you two things: it’s not as bad as you think. But it does require some thought.
In this post, I’m breaking down how you can apply box molding to your own wall, including:
- Planning procedures
- Materials to buy
- Step-by-step process
And if you were wondering, this project took us about one week (but you could do it faster if you wanted).
What is box molding?
You probably already know what box molding is considering you are seeking out a tutorial. But if not, box molding (or picture frame molding) is a type of trim molding that adds texture to your flat wall. It’s often used to make rectangular or square borders, which look fantastic with gallery art walls, sconces, mounted televisions and more.
How to map out your wall for box molding
I used Pinterest to get a good idea of what paneling we wanted to pursue. Our living room wall has a fireplace so we had to get a mountable television. I also knew that I wanted longer rectangles so I could feature my favorite piece of artwork, my dad’s New Yorker poster that was passed down to me. However, you could make your boxes all the same size.
Use painter’s tape to map it out. This was immensely helpful for us to solidify our decision. It doesn’t have to be straight or prefect of course, but it helps a lot to do this before making permanent choices.
Do some math. Not my strong suit, so Nathan took the lead with this one. For our fireplace wall, it’s split into three panels that are not equivalent in size, so this required some careful thinking.
- Measure the height and width of your walls, but don’t include any existing ceiling or floor molding into the calculations, JUST the wall. We have bottom molding as you can see, and we did not measure that part.
- Apply the 4 inch rule. We wanted 4 inches of space between the bottom of the wall (start at the edge of your floor molding if you have it) and the first piece of box molding. We also wanted 4 inches between the bottom box and the top box, and another 4 inches between the topmost piece and the edge of the ceiling. That way it looks evenly spaced out with a nice border.
- Calculate your ratios. We decided that the top rectangle should be three times the size of the bottom one (to give us the look we wanted for the wall above with the TV and fireplace). In simple math, the bottom box is “x” and the top box is “3x.”
- Calculate your vertical wood pieces. Here’s the equation to use:
3x + x = (height of the wall – 12 inches). The twelve inches comes from the 4-inch spaces that need to accounted for (there’s three of them). Solve for X!
- Calculate your horizontal wood pieces. Horizontal is easier because they all can be the same size as each other regardless of the height of the boxes:
Width of the wall – 8 inches = horizontal length needed. The 8 inches comes from 4 inches of space twice to account for the left and ride sides of the wall.
If you do one large, flat wall, you can do less math, but you will need to remember the four inch rule between all of your boxes and subtract that from the full height and width of the wall.
Supplies needed for box molding
Here’s everything we used for this project:
- Primed PVC Base Cap Moulding – we purchased this exact material from Home Depot. We used this instead of wood because it is much easier to cut (by a lot). It looks just like wood trim after you paint it, so we had no problem using this.
- Miter shears – these sharp scissors are from Home Depot and they cut through PVC pipe easily, so no need for a whole saw and miter box. These shears have a 45-degree angle to make the perfect box cuts that you need! Remember that you need to cut your pieces on an angle so they fit together like picture frames.
- Tape measure – critical to measure the walls and determine the length of our pieces.
- Level – helpful to make sure that the pieces are straight as we nail them to the wall.
- Caulk and a caulk gun – this will provide a finished look before we paint them, creating a more seamless transition between the wall and the molding.
- Nail gun with a compressor – we used this to nail the pieces to the wall. We borrowed one from Nathan’s parents but you can also rent them from Home Depot, which is easier than buying!
- Primer and Paint – be sure to buy the same exact color and finish of your current wall (unless you want to paint them a different shade!). If you were curious, our walls are Drift of Mist in eggshell finish from Sherwin Williams.
- Wood filler – to fill in the holes in the PVC made by the nail gun. It doesn’t matter what color since you paint over it.
- Painter’s tape – to mark your walls and help you figure out where you want the boxes to go.
- Paint brushes – We bought some narrow ones from Sherwin Williams.
- Pencil – helpful to mark the wall where you want to apply your molding.
- Wet paper towel or baby wipes – this is useful to smooth out the caulk once you pipe it across the molding.
How to apply your box molding to the wall
Step 1 – Make your cuts.
After measuring the walls and making your calculations, use your tape measure to measure out where to make your cuts in the PVC. Mark it with a pencil and then use your miter shears to carefully make all of your cuts (at a 45 degree angle!) I also used the pencil to mark which side of the wall each piece goes on to make it easier to remember, like “vertical, bottom, left of fireplace.”
The corners should line up well, but they don’t have to be perfect puzzle pieces.
Step 2 – Prepare to nail your molding
Remove your painter’s tape and use a pencil and your measuring tape to make small markings on the wall where you want the molding to go. Be sure to use the four inch rule and draw small marks from the bottom and sides of the wall. We started with the bottom boxes and found that easiest.
Line up your piece to the wall – it’s helpful to have a buddy sometimes for this. Place the level on top of the piece to make sure it’s straight as you hold it in place. Then use your nail gun to secure it in place. The amount of nails you need is kind of up to you – I would suggest at least three but you will need more than that for the longer pieces!
Step 3 – Fill the holes and crevices
Use your wood filler to fill two things: 1. The nail gun holes. 2. Any cracks or crevices that are apparent in the corners of each box where the wood pieces don’t align perfectly.
We took the food filler with our finger and just smoothed it into the cracks and the holes. Take a baby wipe or paper towel and wipe away the excess to keep the surface smooth. Let it dry.
Step 4 – Caulk and seal
The caulk will make the pieces look flush and seamless against the wall. Use your caulk gun to carefully squeeze a straight line on the borders of each box (both the inside perimeter and the outside perimeter). Use a wet baby wipe or paper towel to go over the caulk while it’s still wet to smooth it out and remove the excess. Let dry.
Step 5 – Prime and paint
Paint each piece with primer. I recommend at least two coats for an even finish. The guy at Sherwin Williams said the primer wouldn’t work well on PVC. Well, he was wrong, it worked perfectly fine. Let that dry and then paint on the wall paint you’d like. We did the exact same shade and finish as the rest of the wall so we didn’t have to be super neat about it, but we did do about 2-3 coats to ensure no streaks occurred and that it was nice and matte.
What if there’s an outlet in the way?
We had this issue and decided to just cut and nail the pieces around as not to disrupt the rest of the wall’s design. Final verdict: I think it looks fine. Instead of cutting the pieces on a 45 degree angle, just cut them straight up and down so that they align with the outlet cover.
I don’t even notice it compared to the rest of the wall.
How to mix up your designs
The other side of the wall (not the one with the fireplace) is different because I wanted to include a gallery wall in one large rectangle, followed by two skinnier rectangles to place sconces. So a couple things to note if you like this design.
- Use painters tape to map it out – again, that’s the easiest way to see if your design is going to work for you!
- Decide how large your smallest boxes will be – we decided that the skinny boxes with the sconces would need 1 foot (12 inches) of space so that the sconces would fit when we installed them.
- Do your math again – Since this is one continuous wall, you have a lot more 4 inch spaces to take into consideration (we have five groups of boxes across). That means that 24 inches of space will be subtracted from your horizontal lengths. So, knowing that the two thinner boxes are 12 inches each, subtract (12 x 2) + 24 from the width of your whole wall. That will give you how many inches you have left to play with.
- Play around with what you like – the size can really vary here, which is why taping it first is helpful to see how it will look. Determine where each skinny rectangle should start and measure where that would be: a quarter way across, or a little less? Copy it on the other side. Then use the four inch rule to determine the squares on the right and left of them.
Have other questions? DM me on instagram: @caroline_hoffman. I love how our walls turned out and I’d love to help you figure it out if you need assistance!
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