Cornice valances or cornice boards can dramatically change the look of a room and window coverings. Making your own cornice valance gives you complete design freedom. A styrofoam cornice can easily be made from either a styrofoam sheet or foam insulation board. Finishing touches, such as buttons, ribbon and other ornamental items, can be added to provide a personalised look.
Use a steel measuring tape to measure the outside width of the window frame. Add 4 to 6 inches to the overall measurement, depending on the existing hardware on the window.
Measure the depth from the wall out to the end of any existing window covering that protrudes from the window. Add 2 to 3 inches to this overall measurement to clear any window coverings.
Lay foam insulation board on a flat surface.
Mark off the appropriate styrofoam pieces using a yardstick to measure the foam board and a utility knife to score the board. Scoring requires running the utility knife lightly across the foam insulation board using the yardstick as a guide. Score one piece using the full width measurement of the window; this piece should be between 8 and 10 inches long --- the measurement from where the top of the cornice valance will hang to the bottom of the cornice.
Measure another piece the full width of the window width. The length of this piece should match the measurement from Step 2, between the wall and the end of the existing window treatments. This will be the top of the cornice, which will lie across L-brackets. Use the yardstick to measure off the piece and score it with the utility knife.
Mark off the last two pieces with the yardstick. The width of these two sections should match the measurements from the wall to the existing window treatments and should measure the same length as the large cornice valance piece. Score the piece with the utility knife.
Break apart the pieces one at a time. The styrofoam, if scored properly, should break easily. If the pieces do not, use the utility knife to cut deeper into the styrofoam.
Spread hot glue along the edges of the styrofoam board. Connect the boards to make an open box containing a large front piece, a top and two sides. Allow the glue on the styrofoam board to dry completely, for approximately one hour, before applying fabric to the board.
Cut the desired fabric for the cornice valance. To cut the fabric correctly, add the width of the large front piece with the width of the two side pieces and add 6 inches to the overall width. The extra amount of material allows the fabric to be folded on the back of the cornice so the raw edges of material do not show. The length of the fabric should be the length of the cornice plus 6 inches. For example, if the overall cornice length is 10 inches, cut the material at 16 inches.
Lay the fabric on a flat surface, with the front, colour-side of the material facing downward. Set the cornice on top of the fabric with the large front cornice piece facing down.
Spread glue with a hot glue gun along each piece, beginning about ½ inch from the edges of the boards and covering at least 2 inches of the back of the board. Fold the material over the back of the cornice, pulling tightly as you fold the fabric over the glue. Repeat until the material covers the entire front of the cornice. Keep the cornice in this position until it has dried completely.
Attach L-brackets to the wall using a cordless screwdriver and screws.
Lay the finished cornice on top of the L-brackets.
If hot gluing the fabric to the front of the board, spread the glue evenly to ensure there is no bubbling.