Measure the inside length and width of the shed's window frame with a measuring tape.
Measure your window glass or acrylic with a measuring tape -- the two pieces should be the same size -- each 3 inches narrower than the shed's window frame and half as long plus 1/2 inch. Cut four pieces of 2-by-2-inch wood to the length measurement minus 1/2 inch and four pieces to the width measurement minus 1/2 inch with a saw. Two length and two width pieces will form a rectangle to frame a piece of the window material. Each of these frames is called a sash.
Cut the ends of the sash pieces at 45 degrees with a miter box and a saw so the length and width pieces meet in mitered corners.
Draw lines down the center of the inside edge of each sash piece where the glass will sit. Set your circular saw at 1/4 inch and run it along the lines to cut grooves for the window panes.
Nail three sides of the sash together through the corners with 4-penny nails and slip the window glass in before nailing the fourth side on.
Cut pieces of 1/4-inch molding to match the inside measurement of the sash. Miter the edges as with the sash. Gently tack it around the window glass on both sides of the sash to hold the panes in place. Don’t glue the glass in: it must be able to move in the sash to withstand temperature changes.
Nail an inner frame of 1-by-1-inch molding along the outer edge of the inside of the shed's window frame.
Line up the top sash in the frame. Secure the top sash with 1-by-2 braces, cut to fit between the sill and bottom of the sash, directly under the uprights of the sash with the 2-inch face of the wood to the window frame. Nail the braces in place with 4-penny finish nails.
Set the bottom sash in the window against the braces you just installed. The top of the bottom sash and the bottom of the top sash should overlap exactly. Use construction glue to attach a strip of 1-by-1-inch molding cut to fit along the top, or header on the "in" side of the frame where the bottom sash will move Add two more strips of molding on the inside edges of the jambs down to the sill to guide the bottom sash as it moves. Check to ensure that the bottom sash moves easily up and down in the frame and attach the side molding with 4-penny nails.
Screw in window locking hardware, with included screws and appropriate screwdriver, where the two sashes meet.
Things You Will Need
- Tape measure
- 2-by-2 window framing
- 2-by-6-inch window framing
- 1-by-2-inch frame molding
- 1-by-1-inch frame molding
- 1/4-inch molding
- 2 pieces window glass or acrylic
- Circular saw
- Miter box and saw
- 2-, 4-, 6- and 8-penny nails
- Window twist lock
- Add trim to cover framing elements. Add a sill or vinyl sill wrap to drain water away from the bottom of the window.
- Paint window frame parts before assembly to seal wood and wrap the wall framing with adhesive membrane to protect against moisture.
- Sash guides are not needed for casement windows. Hinge single-sash windows directly to the outside of the window frame.
- Check local resale or salvage for small window sashes. A bit of sanding and painting will render a like-new window and save some effort.