How to Install a New Vinyl Window

There are two ways to install a new window. The first is an insert which leaves your old window frame and interior trim intact.

The second way is a complete window with new brickmold and interior jamb extensions.


This picture refers to the insert installation and that is the most economical way but not necessarily the best as you are using an old frame without knowing   how well it is insulated as well as reducing your glass area.

Insert Installation

The new insert should be no more than 1/4" smaller on each side as well as the top and bottom to allow for insulation but still butt up against the inside stops.

From the outside remove the exterior or blind stop and remove both the upper and lower sash. Leave the stool or sill and the interior stop in place. These will be used for the new window to butt up against and will eliminate any inside work or repainting.

Insert the new window from the outside up against the inside stop and shim in place and then screw into place. There are several places on the sides of a vinyl  window to screw thru the frame so the screws won,t show. Drill a pilot hole and coat the screw with silicone before inserting. This will ensure that you won,t get a  leak around the screws.

Insulate the opening between the new window and old frame. Cover the gap with a piece of wood trim and repaint or you can cap all outside wood with aluminum.

New Install (total tear out)

Remove interior casing to expose old window frame.

Measure the interior frame size of the old window  and then measure the complete outside size including brickmold.

Next measure the jamb depth (usually 4 9/16 or 6 9/16) and order a new window as close to but not larger than these sizes.


Completely tear out the old window and clean up the opening. From the outside insert the new window and check that the jamb extension is flush with the drywall.

Shim the bottom ,sides and top of the window so that you have an even gap all around the window.

Fasten the window in place and open and close a few times to make sure it is working properly. Insulate with fiberglass or low expansion foam.

Important Note

Never put a screw thru the bottom of a vinyl window as this is a drainage area and will cause a leak.

If your measurements were correct you should only have to caulk the brickmold outside and install new casing inside.

With new windows proper measurements are critical for an easy install.

Now that you have the know-how, check out the lines of windows we carry at our Windows product page. And don't forget to make sure you have all the Tools before you get started. If you have any questions about installing your window, or want to place your order and get started right away, Contact Us today.