How to Add a Window Opening in an Interior Wall

If you want to add a window to an interior wall, you don’t necessarily need to hire a contractor to complete the project. If you’re a homeowner who considers themselves to be handy then this is a project that you can tackle with great results. All it takes is four easy steps.

Step 1 - Layout the Window

Once you’ve picked a location, find the center point of the window and add 1 inch to each side of its overall width. For example, if the window is 32 inches wide, then measure 34 inches or 17 inches from the center point and make a mark with your pencil. Now repeat the process for the height of the window. Then take your 4 foot level and draw an outline of the enlarged shape of the window.

Step 2 - Cut the Opening

The next step to add a window to an interior wall is to cut out the rough opening. Before cutting, take a moment to make sure there is no electrical wiring in your way. After a quick check, grab your sawzall and cut along the lines. Use your hammer and crowbar to remove any remaining studs.

Step 3 - Frame the Opening

The proper framing is essential if you want to add a window to an interior wall. Use the circular saw to cut the 2x4 into a king stud which will run from the top plate to the bottom plate. Next cut the jack stud so the top of the stud is flush with the top of the rough opening. Nail the jack stud to the face of the king stud and position them so that the face of the jack stud is flush with your cut opening. Now repeat the process for the other side of the window. Next, it’s time to install the header which supports the weight of the framing and drywall above the window. Measure the distance between each jack stud and cut each 2x6 to that length. Fasten the 2x6’s together and place one end on each of the jack studs. Then nail the header to the king and jack studs.

You’ll need to install a sill to support the bottom of the window. Cut a 2x4 so that the top of the stud is even with the bottom of your rough opening. Fasten the 2x4 to the bottom face of the jack stud. Repeat the process for the other side. Now cut a 2x4 to fit between the face of each jack stud and fasten it to the top of the 2x4’s you’ve just installed. Lastly, cut and install the cripples studs above the header and below the sill.

Step 4 - Install the Window

The last step required to add a window to an interior wall is the easiest. Set the window into the framed opening and use wood shims to adjust for level and plumb. When fastening the window to the frame, make sure you position the fastener to catch the shims.