How to Make a Cornice Board for a Window
- 1). Measure the width of the window. Add 3 ½ inches to each side to allow for the thickness of the 1-by-4 framing boards. Determine the height of the cornice board. Add 4 inches above the window frame for typical mounting.
- 2). Cut the 1-by-4 board to the width measurement. Use a circular saw or have the lumber yard cut the boards for you. Cut two 1-by-4 pieces to the height measurement.
- 3). Sand the cut rough edges of the 1-by-4s. Glue the top edge to the side frame. Repeat for each side.
- 4). Attach the frame top to the frame sides with the finish nails. Wipe excess wood glue off with a damp cloth.
- 5). Measure dimensions of the outside of the frame. Cut plywood to that measurement.
- 6). Square the frame by using a carpenter's square. Place the square inside the frame at each corner, laying the long edge flush with the edge of the wood. The other side of the square should line up with the other edge of the wood frame to be square. Adjust the pieces of wood until square. An alternative to the carpenter's square is to lay the frame on a flat surface. Measure from corner to opposite corner of the frame. Do the same for the other opposing corners. Move the sides of the opposite corners until each corner to corner measurement is the same. Attach plywood to the front using wood glue and finish nails.
- 7). Place the finished cornice board on quilt batting. Cut batting large enough to fold over to the inside of the frame and front. Fold in the corners. Cut off the excess and staple batting to the frame and front.
- 8). Lay the cornice board with batting on fabric. Staple fabric to the inside of the frame and front. Cut off any excess fabric. Fold corners in neatly for a professionally finished look. Keep your fabric pattern straight and even when stapling.
- 9). Attach the “L” brackets to the wall using drywall screws and drill. Put them at least 2 inches above the curtain rods. Set the cornice boards in position on the “L” brackets. Attach the top of the frame to each L bracket by screwing through the bracket into the cornice frame from the inside.