Tip 16: Boxing in basement windows - two methods
1. Build a three-sided valance around each window. Use 1/4" plywood for the top. For the three sides, use 1" white pine wide enough to accommodate the ceiling drop and the molding being used. Make certain that the valance is wide enough to allow the window to open and long enough to provide for an open drapery. In most cases, a length of 18" more than the window width is sufficient for the drapery (about 9" on each side of window).
2. Attach the top of the completed valance to the bottom of the ceiling joists.
3. Install the appropriate wall molding at the level desired.
To box in a basement window, use Armstrong fascia molding. Packed five pieces in a box, this molding is available in 10' lengths and three widths.
#7814...............4" fascia molding
#7816...............6" fascia molding
#7818...............8" fascia molding
The molding is finished on the inside and bottom.
1. Notch the front or sides (depending on the joist direction) to fit under the joists.
2. Bend the molding to the indicated shape. Be sure to make the box deep enough for the window to open and make the box wide enough to allow drapes to be installed. In most cases, a length of 18" more than the window width is sufficient for the drapery (about 9" on each side of window).
3. Use screws to fasten the flanged ends to the wall. Use angle clips to fasten the front (or sides) to the joists
4. The bottom lip is already formed to a 15/16" dimension, the same as the field grid. When finishing the corners, use 15/16" outside corner molding covers (Armstrong #7863WH) to close the void.
5. Finish the inside of the box by fastening drywall to the bottom of the joists inside the box. Angle molding can also be fastened to the sides and inside front of the box to allow an acoustical panel to be laid on a slope inside the box to close off the top of the box.
Tip 17: Installing decorative molding on boxed-in area
If you want to continue using the same decorative molding on the boxed-in areas that you are using on the rest of the room, you should make your box deep enough. For wood molding, allow for the tile and ceiling tile track and clip (1-1/4") or the panel and the depth of the suspended ceiling drop, the height of the molding and the desired reveal at the bottom of the molding.
If you want to use metal wall molding around the box, again you should allow for the tile track and clip or the panel and the depth of the suspended ceiling drop.
Fasten the molding to the box using finish nails or adhesive.