How to Replace Window Glass: Vinyl Window Installation

Knowing how to replace window glass can save you a great deal of money over the lifetime of your home. Vinyl window installation is fairly basic, with just a few noticeable exceptions. Here's how to do it.

Vinyl Window Installation: 4 Steps

1. Remove the old sash. A traditional double-hung window has two sets of removable stops--an inside stop that holds the lower (inner) sash in place and a blind stop that separates the two sashes. The outside stop is nailed to the edge of the sash and is immobile.

2. Set the replacement window in the opening. Make sure it fits snugly between the stool on the inside and the outside stops of the old window. If necessary, nail a strip of wood to the jamb to fill the gap between the window and the outside stop if the new window is narrower.

3. Make supports for the window. Plane the edge of a board at an angle that roughly matches the slope of the sill, then rip a strip of wood to match the gap. Install the support strip by cutting it to length and nailing it in place directly beneath the point where the front edge of the new window will rest.

4. Center the window in the opening. Use a carpenter's square to check that the window is square, then shim the sides of the window directly behind the pre-drilled screw holes in the jamb as needed. Screw the window in place through the side jambs and then replace the inside stop.

Complete the project by going inside and checking the window to make sure it operates properly. Then, run a narrow bead of caulking all around the outside of the window to seal the gap.