How to Build an Interior Window

Interior windows are an unexpected design feature in a home that allows natural light to flow from one room to another. Adding interior windows is also a great way to make a room feel more open without completely removing a wall.

In the flip house, we thought about removing a wall between the family room and living room but decided that the rooms would be more useful if we left it. So we decided to add two interior windows to the wall, one on each side of the media built-ins that I built.

In this tutorial, I’m going to show you exactly how I did it.

Tools & Materials

  • Miter Saw
  • Finish Nailer
  • Table Saw
  • Level
  • Tape Measure
  • Pencil
  • Multi-Tool
  • Reciprocating Saw
  • 1×2 Primed Pine
  • Glass
  • Black Spray Paint
  • Silicone
  • Caulk Gun
  • 2x4s

Step 1: Determine the Interior Window Placement

Before you start building your interior window, you need to decide where it will be placed. As I mentioned above, we added one window on each side of the media built-ins. I decided on a size for each window and then centered it up in the available space.

I used a level to mark where the wall would need to be cut out.

Step 2: Cut Out the Opening in the Wall

Using a multi-tool, I cut out the drywall along the marks I made. Then I used a reciprocating saw to cut out the studs in the opening. Then I added new studs to each side. And since this was a load-bearing wall, I had to add headers above each window.

Step 3: Wrap the Opening

For our openings, I decided to simply wrap them with drywall, but if you prefer, you can trim them out with moulding.

Step 4: Measure the Opening

Once the new interior window openings were finished, I measured the width and height. I used the dimensions to size the pieces of glass, which I ordered from One Day Glass. I was a little nervous about ordering large sheets of glass online, but everything was smooth with the ordering and delivery. Although, they did cut the first two pieces two short. They quickly corrected the problem by sending out two new pieces. So it only caused a small delay.

I also used these measurements to determine how many pieces of 1x2s I would need.

Step 5: Cut and Paint the Frames and Grilles

Using a table saw, I rip cut 1x2s down the middle giving me 3/4″x3/4″ pieces. I used these for the frames. Then I rip cut 3/8″ off of the smooth sides of 1x2s leaving me with 3/4″ x 3/8″ pieces. I used this for the grilles.

Once I had all of my pieces cut for both windows, I painted them all using black satin spray paint.

Step 6: Build One Side of the Interior Window Frame

After the paint had dried, I used 2″ finish nails to fasten the inside frame pieces to the opening. I offset the inside frame about 1/16″ off of the center to account for the glass thickness.

Step 7: Insert the Glass

Using a caulk gun, I applied a bead of silicone along the inside of the frame. Then I placed the glass against it, pressing it along the edges. I made sure that the glass made good contact with the silicone.

Then I repeated step 6 for the outside frame.

Step 8: Add the Grilles

I decided to go with a 2×4 grille pattern for these windows to match the pantry door. This along with the overall height and width determined how long I cut the grille pieces in step 5.

I applied a bead of silicone to the back of each grille piece and stuck them to the glass. I used a small level to make sure each piece was straight. And I worked on one side at a time. Then I moved to the other side.

Step 9: Finishing Touches

After I had both windows built, I filled the nail holes and touched up the black paint.

Brooke and I both loved the way these interior windows turned out. It added a nice pop of black beside the built-ins and allows a lot of natural light to flow into the sitting room beside the kitchen.

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1 Comment

  • Reply Jenn

    Hi! I am wondering what kind of glass you ordered from One Day glass. Also, in your opinion is there a size limit where this doesn’t work anymore. If we had an opening larger than that how would you think about managing that opening?

    February 22, 2023 at 4:23 pm
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