How To Build and Install Picture Frame Molding

It’s so hard to focus on DIY projects this time of year. There are baseball divisional series going on, hockey is underway, football is in full swing, golf is still going strong and basketball season will start any day now.

Not to mention that the weather is fantastic!

But yet, a weekend warrior must soldier on to keep on top of home projects.


My DIY project this past weekend was cutting and installing picture frame molding in the dining room. (Yes…I snuck in a little game time, too!)

This photo shows the picture frame molding before it was painted.


Reasons To Install Picture Frame Molding

Installing picture frame molding in the dining room has been a rewarding project because:

a) It adds a touch of class for cheap.
b) It adds a great final touch to the room.
c) It’s not a difficult undertaking (unlike the crown molding I put up a few weeks ago), yet the results are great.

What follows are the steps I went through to get the dining room picture frame molding project underway and to bring it to completion.


Planning, Measuring, And Gathering Supplies

The first thing I did was to take measurements of each wall below the chair rail.

I also drew a detailed diagram with all of the measurements. That might be a little much for some of you who would rather just write some measurements on a sheet of paper, but it helps me keep on track and speeds the process for me.

picture-frame-molding-diagram.JPG picture-frame-molding-plan.JPG
I did a little math and figured out how much molding I would need. The molding I choose came in 8′ sections so I had to combine different lengths that would be needed to make the most use of each piece of trim molding. I also added about 15-20% for waste and mistakes.

We went to the local home improvement center and picked out a molding profile that would compliment the existing chair rail and crown molding that I had installed previously. We actually had picked out the picture frame molding at the same time we bought the rest of the molding for the room, but it’s up to you.

I already had these things on hand to complete the project:

  • measuring tape
  • pencil
  • level
  • carpenter’s wood glue
  • #18 x ¾-inch zinc plated wire brads
  • hammer
  • compound miter saw
  • nail set
  • wood filler
  • sandpaper
  • paint and primer

When I measured the walls, I figured how many inches looked good as a spacer between the edge of the wall and where the first piece of molding would be installed. In my case, I liked 3½ inches for my spacer.

I had also looked at how far the gap was on new houses I had been looking at, in order to get a good idea of industry standard. I used the same 3½ inch distance on top, bottom, and in between each picture frame box.

However, I did make an exception on the wall of the dining room where the full length bay window is located. Since the gaps between the walls and window casings are narrow, I squeezed it in by 1 inch.

I wanted all of the walls to look symmetrical, but it just didn’t look right to me because the picture frame boxes would have been too narrow.


Cutting & Installing The Picture Frame Molding

You will need to cut 45° angles with the thinnest (and fanciest) part of the trim on the inside of the box.

All of your vertical pieces should be the exact same length, with the exception of any walls where you might have an HVAC return/vent or electric socket to cut around.

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I cut my first vertical piece and used it as my template for the remainder of the vertical pieces. I simply put the flat edges back-to-back and drew my lines on the face of the trim so that I knew where to cut. This will give you a consistent length throughout.

WARNING: Be careful! Keep your fingers out of harm’s way when using the compound miter saw, and always use safety glasses.

compound-miter-saw.JPG line-up-molding-when-cutting.JPG
I did the same for the horizontal pieces as well, except when it came to making cuts to trim out around the HVAC return.

picture-frame-molding-bay-window.JPGThe other notable exceptions were all of the special 22½° cuts that were required for the bay window angles. They all had to be cut as individual units because the lengths were not consistent between the gaps, although I did place the top piece up against the piece to be cut, drew my line and then made my cuts in the opposite direction for the bottom. This way, I knew it would square up.

The next part is a little tricky. I made a measurement on the wall 3½ inches away from the side and top and made a small mark on the wall. This was the starting point to place my first (horizontal) piece.

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I then got my level and placed it on top of the molding. Once it was dead level, I drew a faint line across the top (or bottom, your choice) of the molding. Don’t worry about the line because you will paint the molding and wall when you’re done.

If you DO NOT have a nail gun, then you will need to pre-nail your brads/nails. This will free up a hand to hold the hammer while you hold the molding level.

TIP: I placed the molding on top of my aluminum level and lightly hammered the nails in until they tapped the level. This kept the nails from protruding through the backside of the molding and freed up a hand to hold the trim while I hammered it in.

I spread a thin layer of carpenter’s wood glue along the backside and on the ends of the molding. Good contact is essential in order to keep the molding flush to the wall — so be sure and press along the length of the molding once you’ve nailed it to the wall. I used 3 nails per piece of molding; one in the center and one on each end. Don’t nail it any closer than about 1½ inches from the end of the molding, or the wood may split on you.

glue-on-picture-frame-molding.JPG nail-set-picture-frame-molding.JPG
I suggest that you nail the top piece first, then both sides. Do not nail in the bottom nail of the vertical molding until you are ready to place the bottom horizontal piece. This allows you to make slight adjustments — left or right — in order to square it up for tight joints. Hammer in the remaining nails once you are satisfied with how the angles meet.

Run your finger along the edges and where the 45° angles meet, in order to remove any glue that may have squeezed out.

Grab your nailset and tap in the nail heads just below the surface of the wood. Take it easy, or you may pound the nail all the way through the molding. Nailsets have different tip diameters for different nail head sizes. I have a couple of them, but I used the thinnest one for this project for obvious reasons.

Once you have completed all of your picture frame molding boxes, it’s time to fill the nail holes with wood filler. There are different types of wood filler.

A friend of mine told me that he learned a carpenter’s trick from a contractor that did some work in his home: use window glazing to fill nail holes instead. You may not need to sand it because you can wipe it flush when you apply it. Try it!

Now, the only thing left to do is prime and paint it your picture frame molding. You may choose to paint the inside of the picture frame box a darker shade than the remainder of the wall surrounding it to make it stand out.

And that’s all there is to it! (NOTE: This project will go faster if you turn the game off.)

Must read:  My Best Tips For Learning How To Cut Crown Molding Yourself

Randy Boerstler

Randy Boerstler

Writing a home building blog that chronicles new homes during different phases of construction from a consumers' point-of-view is rather unique and loads of fun. Basically, my tips are a collection of checklists for what I think should (and should not) go into building a quality home. So let's have fun seeing what's new in the housing market these days!

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  • Tyol82

    As a new homeowner who has been doing a lot of molding in the past year, I would recommend painting the molding before cutting and nailing. It’s much easier to touch up the paint afterward than tape, lay down canvas, kneel, prime/paint etc..

    • Randy

      @a4792466432841538aab1f14b7035a6f:disqus …I concur. If you have the luxury of painting prior to tacking it to the wall, it will reduce the difficulty level and amount of time spent painting.