How do you install replacement sliding windows?

Begin the installation for a replacement sliding window by first measuring the opening for a new window. Then remove the old window by lifting the panel up and pulling the bottom out. Replace with a new window by installing a sill strip, applying sealant and setting the window into place.

Always take every necessary safety precaution when working with glass such as wearing goggles and gloves. Follow the steps below to replace sliding windows.

1. Measure the existing window

Before purchasing a new window, measure the opening for the existing window. Purchase a sliding window that has the same measurements.

2. Verify that the replacement fits

Verify the replacement window can fit in the opening by comparing its measurements to those of the opening.

3. Open the window and remove the moveable panel

Open the window all the way and lift the panel up and out. Remove the vertical panel that holds the window in place by tapping it away from the fixed panel. If the bar is held in place by a screw, remove the screw.

4. Lay down a wooden strip

Lay down a wooden strip on top of the window sill where the replacement window will sit.

5. Dry-fit the window

Dry-fit the window and mark where it will sit on the wall.

6. Apply sealant

Apply a liberal amount of sealant to the sill strip and the outside face of the existing frame.

7. Get a helper and fit the window

With the help of another person, fit the window into place. One person needs to hold the window in place so the other can attach the window using screws with hinged covers. Do not over-tighten the screws.

8. Check and adjust as needed

Once the window is securely in place, make sure there are no gaps. Open and close the window several times to check for a tight fit.

9. Apply finishing caulk

Give the window a finished look by applying finishing caulk around the edge of the frame. Leave two or more small openings in the caulk line to allow moisture to escape.