How to Install Replacement Windows in a Basement

Installing new basement windows will prevent heat loss from the basement due to cracked or poorly insulated old windows. Basement windows are smaller than most other types of windows, and are usually one of a few standard sizes. Double-check your measurements before you buy a window off the shelf. Some basement windows open, others don't, but the installation method is the same.

Things You'll Need

• Tape measure
• Hammer
• Pry bar
• Replacement basement window
• Wood shims
• Short level
• Mounting screws
• Screw gun
• Caulk
• Spray foam insulation

Instructions

1. Measure the opening with the existing window still in place. Subtract 1/2 inch from the height and width measurements. Order the replacement window to those dimensions. Don't remove the old window until the new window arrives.

2. Remove the old window from the opening, prying it out at the frame with your pry bar and hammer.

3. Set the new window in the opening. Put a level on the window, and slide shims along the bottom and sides until it's level.

4. Secure the window by driving mounting screws through the screw holes on the sides of the unit and into the surrounding frame.

5. Caulk around the exterior perimeter of the window.

6. Fill the space under the sill, in the inside, with foam insulation. Caulk around the rest of the interior.

Tips & Warnings

• Wear eye protection when extracting the old window.

References

• ThisOldHouse.com: Replacing Basement Windows.