How to Install a New Window
If you don't like your view, the window may be the problem. Replace it with these step-by-step instructions.
Materials and Tools:
casement or picture window
1-by-10-inch lumber (6-foot length)
air compressor and hoses
1. Measure your space and buy a window the same size as the existing window.
2. Remove all screens and the upper and lower sashes of the windows.
3. Cut the caulk along the seams with a utility knife.
4. Remove the window casing inside and the outside storm frame. Unscrew the window frame and carefully remove it.
5. Test-fit the new window.
6. Remove the window and use a caulk gun to apply silicone sealant to the bottom corners of the rough opening. Starting on the lower sides, cover the bottom of the sill with aluminum weatherproofing tape. (The butyl adhesive backing prevents any water from penetrating the sill.) Apply silicone sealant to the edge of the window ledge and the corners at the ends of the sill.
7. Set the bottom of the window in place, and then tip the frame upright and push it against the stops.
8. Make sure that the window frame is square, and then install shims at the top, bottom and middle of the sides of the frame. Check that the gap between the sash and the frame is uniform from top to bottom. With the frame square and locked in position, run screws through the pre-drilled holes in the sides, through the shims, and into the jamb. Use a utility knife to score the shims and break off the excess.
9. Fill the small gap between the edge of the frame and the window opening with low-expansion foam, which is made expressly for this purpose.
10. Cut and replace the casing on the inside, prime and paint to match. Outside, form a watertight seal between the replacement window frame and the original opening by pressing the foam backing rod into place. Fill the remaining space with silicone caulk.