A cornice provides a window with a finished look. It extends from the top of the window, running horizontally across its width. The cornice is great for hiding window treatment hardware and refining the look of this area. With the proper tools and equipment, any of us can build this decorator accessory in a day.
You will need:
• 1×6-inch board
• 1×8-inch board
• Chair rail molding
• Quarter-round molding
• Circular saw
• Miter saw
• Drill bits
• Nail set
• Wood putty
• Finish nails
• Wood glue
• Primer (optional)
• Paint or stain (optional)
• Paintbrush (optional)
• Fabric or paper (optional)
• Drywall anchors
• Drywall screws
• Small wood screws
• Safety glasses
• Measuring tape
• Straight edge
Step 1: If the cornice will be stained or painted, use poplar or fir wood on the sides and front. Pine can be used if the cornice will be covered with paper or fabric. The board placed on top will not show- it just keeps dust from accumulating on window treatments.
Step 2: Use the tape measure to measure from one edge of the top of the window to the other. Add 2 inches and transfer this measurement to the 1×8-inch board. Measure each window separately if building multiple cornices.
Step 3: Cut the board to the proper length with the circular saw, forming the front piece. Create the top piece by cutting the 1×6-inch board to length. To form the sides, cut two 6-inch boards.
Step 4: Dry fit all pieces, mark pilot holes, and then drill them. Use the finish nails and glue to assemble the cornice boards. Sand all rough areas with the sandpaper.
Step 5: Add chair-rail molding to the bottom and top of the cornice to provide a finished appearance. The cornice boards should serve as guides for measurement. Mark one width of molding for the top and one width of quarter-round trim for the cornice bottom.
Step 6: Sand all rough edges on the trim and cut it to size with a miter saw set for a 45-degree outside cut.
Step 7: About 2 inches from the top on both ends of the molding, place a mark with the pencil. Use a straight edge and the pencil to connect these two marks. The top end of the molding will extend above the cornice and this line helps to properly align the molding onto the cornice.
Step 8: Dry fit the longest molding piece, making the line created in Step 7 flush with the cornice top. Drill pilot holes and then use finish nails and glue to attach this molding to the cornice. Drive the nails below the wood surface with the nail set. Use wood putty to fill the nail holes.
Step 9: If the cornice will be painted, apply one coat of primer, allow it to dry, and then apply a coat of paint. Alternatively, apply stain or glue paper or fabric onto the cornice.
Step 10: Determine the area of the window to be covered by the cornice. Make a straight line on the wall to denote the top of the cornice, using the level.
Step 11: Use the wood screws to attach L-brackets to the top area of the cornice. Attach the cornice to the wall, allowing the line created in Step 10 to serve as a guide. Check the placement to ensure it is level and then attach L-brackets to the wall with drywall screws and drywall anchors. Screw in each L-bracket until the cornice is securely attached to the wall.