For first-timers, installing a window frame can be a little intimidating, but if you follow a few simple steps you will find the process relatively easy. While the exact installation methods will vary, depending upon the type of window to be installed, the following general installation guidelines can help you successfully install a pre-hung window. Also, make sure to follow the specific manufacturers’ instructions that come with your pre-hung window.
Prepare the Window Opening
Make sure that the window opening is clear from debris and obstructions. Make sure there are no nails, which have not been knocked down, or excessive amounts of glue or putty that will interfere with the installation of the window frame.
Inserting the Window Frame
Because of the heavy weight of the window, remove the glass or sashes from the window before attempting to install the frame. Next, take the frame and slowly tilt it in place into the window opening. Using some of the shims, pack them into the spacing around the frame, to help hold the window frame and keep it from moving. Then, use your level to make sure the window frame is level and plumb on all four sides.
Reinsert the Window Glass or Sashes
Once the frame is inserted into the opening, and level and plumb, reinsert the window glass or sashes into the frame. This will actually help to square up the frame and keep the frame from tilting when being nailed to the opening. After you insert the window sashes, visually inspect the entire border of the window to make sure that gaps are the same.
Securing the Window Frame
Next, using your hammer, drive three or four 10/12 penny finishing nails into each side jam; this will securely attach the frame to the opening. Make sure the nails are evenly spaced along the length of the side jam. For example, if installing a 4 foot high window frame, then be sure that your nails are spaced 12 to 16 inches apart.
Insulating the Window
Using a shim, pack pieces of the loose insulation into the cracks and gaps between the window opening and the window frame; use enough insulation to ensure there are no gaps or crevices, which will allow air to freely pass through.
Once you have packed the gaps with insulation, cover the outside gaps of the window frame with the insulation tape; you don't need to cover the gaps on the inside face of the window.