How to Install Replacement Vinyl Windows

November 22, 2010

The key to a successful replacement vinyl window installation is measuring to make sure the new window will fit the opening. Measure the window opening horizontally at the top, bottom, and middle, then vertically at the right side, left side, and middle. Use the smallest measurement and order your window ¼" smaller in each dimension. Vinyl windows are manufactured in ¼" increments. If replacing multiple windows, measure each one separately, as they may vary in size.

Installing Vinyl Windows: Six Important Steps

Here is a quick sequence of events explaining how to install replacement vinyl windows. The steps are basic; always read and follow the manufacturer's instructions.

Remove the old sash. Pry off and remove the inside stops. Cut the sash ropes and remove the lower sash, then remove the blind stop and upper sash.

Set the replacement window in the opening and make sure it fits snugly between the inside and outside stops of the old window. Nail in a strip of wood to the jamb if needed to fill any gap between the window and outside stop.

If the replacement vinyl window is not sloped on the bottom to match the sill slope, use a shim to support the window.

Center the window in the opening, using a level and carpenter's square to make sure it is set properly. Shim the sides behind the pre-drilled screw holes in the jamb, and then screw the window into place and replace the inside stop.

From the inside, check to make sure the window operates freely.

Go back outside and caulk around the window to seal it.

Your newly installed replacement vinyl window should give you years of trouble-free service.