Cornice window treatments are decorative bands that cover the top portion of longer window treatments, such as blinds or drapes. You can construct your own by following these steps.
Step 1 - Take Measurements
Measure the length of the curtain rod where you will place the window cornice treatments. You want to add at least another inch and a half to each end of the rod to account for extra room for the cornice.
Step 2 - Cut the Materials
Pick a selection of wood board that has a better finish than plywood. This will be more expensive but will pay off in the long run for a more professional cornice. You are now going to cut the board into four pieces (two longer rectangular pieces that will be the top and front of the cornice and two small square pieces that will be the sides). Mark the measurements from Step 1 onto the board and cut the wood with the table saw or circular saw. Wear your goggles when you cut.
Step 3 - Construct Your Cornice
Piece the two smaller square pieces onto the rectangular front piece first. You can two this a couple of ways. If you plan on just painting your cornice and mounting it, you want to use the epoxy glue to piece them together so that you do not have to worry about screws being visible. If you plan on covering the cornice with some type of decorative fabric, you can just use the drill and screws to piece them together.
After you connect the two side pieces to the front, place the top piece and attach it in the same fashion. What you should have now is what appears like a box with two missing walls.
Step 4 - Finish Your Cornice
Use the sandpaper to smooth out your entire wood construction. You need to do this regardless of whether you are going to paint it or decorate it. If you do not smooth out your cornice, it will look rough when it is painted. It will also be more difficult to attach your decorative fabric to a non-level surface.
When you finish sanding, you can paint your cornice and wait until it dries. If you wish to attach a decorative fabric or some other manner of decoration, use the epoxy glue to piece it on. Make sure you only put glue along the edges of the cornice because if you use too much glue, it will warp and ruin the fabric when it dries.
Step 5 - Hang Your Cornice Window Treatments
Mark on the wall near the window with a pencil exactly where you will place your cornice window treatments. Make sure that you attach it to the one of the wood frame beams and not the drywall. Attaching cornice window treatments to the drywall could damage the walls of your home.