To determine how much weatherstripping you will need, add the perimeters of all windowsand doors to be weatherstripped, then add 5% to 10% to accommodate any waste. Also consider that weatherstripping comes in varying depths and widths.

Weatherstripping supplies and techniques range from simple to the technical. Consult the instructions on the weatherstripping package.

Here are a few basic guidelines:

• Weatherstripping should be applied to clean, dry surfaces in temperatures above 20°F (-7° C).
• Measure the area to be weatherstripped twice before making a cut.
• Apply weatherstripping snugly against both surfaces. The material should compress when the window or door is shut.

When weatherstripping doors:

• Choose the appropriate door sweeps and thresholds for the bottom of the doors.
• Weatherstrip the entire door jamb.
• Apply one continuous strip along each side.
• Make sure the weatherstripping meets tightly at the corners.
• Use a thickness that causes the weatherstripping to press tightly between the door and the door jamb when the door closes without making it difficult to shut.

For air sealing windows, apply weatherstripping between the sash and the frame. The weatherstripping shouldn’t interfere with the operation of the window.