How to Build Wainscoting Squares

Prime the wall where you plan to install the wainscoting squares with a paintbrush or roller, depending on the size of the space. If you did not purchase primed molding, prime it as well.

Measure and mark a line on the wall that is 4 inches below the chair rail. Mark a second line on the wall that is 4 inches above the baseboard molding.

Calculate how many frames you wish to add to the wall. Measure the length of the wall. Leave 2 3/4 to 3 1/2 inches between each frame as well as the outer edges of the wall. Subtract the total amount of spacing from the length of the wall. Divide the amount that remains by the number of frames you want to install. That amount is the width of each frame. The height is simply the distance between the top line and the bottom line.

Mark the location of each frame on the wall, using the measurements from Step 3.

Create a jig to help you make square corners for the frame. Cut a piece of scrap plywood that’s approximate 2 feet square so it has a squared corner, using a circular saw. Draw straight lines along two intersecting edges that are the width of the decorative molding you are using. Attach two pieces of scrap 2-by-4-inch lumber to the plywood where the lines form a right angle.

Cut two pieces of molding to the width of one frame and two pieces to the length you determined in Step 3. Use a miter saw to cut the corners to join at precise 45-degree angles.

Spread some wood glue along the mitered edges of a length and width of molding. Place the jig against the wall at the marks. Place the molding along one side and the top of the jig to bring the pieces together at a true right angle. Press them together to hold the glue. Nail the two pieces together with a brad nailer. Repeat this process for the remaining pieces of wood in this frame.

Move the jig to the next area and build the remaining frames as you built the first frame.

Apply panel glue to the back of a frame. Run a bead of hot-melt glue from a glue gun along the back of the joint. Press the frame to the wall. The hot-melt glue dries quickly and holds the panel until the panel glue dries. Use finishing nails driven into the studs to nail the frames to the wall. Countersink the nails using a nail set.

Continue attaching the remaining frames to the wall. Fill holes with wood putty. Fill any gaps between the wall and frames with latex caulking. Allow the putty and caulking to dry.

Sand the frames with fine-grit sandpaper. Remove the dust with a tack cloth.

Paint the wainscoting and the panels with two coats of paint, allowing each coat to dry completely.