Check an exterior door for worn weatherstripping.

A draft around an exterior door may come from flattened or missing weatherstripping, but it can also come from a door that is warped or out of alignment. Start with inspection and measurement. This keeps the job low risk and helps you buy the right material before removing the old seal.

What you’ll need

• Flashlight
• Sheet of paper
• Tape measure
• Pencil and notepad
• Phone camera

Take it step by step

1. Close and latch the door. Look along the top, latch side, hinge side, and threshold. Use a flashlight to spot daylight or obvious gaps. Do not rely on an open flame to find air leaks.
2. Check the existing seal for cracks, flattened sections, loose adhesive, and missing pieces. Slide a sheet of paper into several closed-door locations. A section that releases much more easily than neighboring sections may need closer inspection.
3. Open the door and photograph how the weatherstripping is attached. Some newer doors use a seal pressed into a narrow kerf, while other products use adhesive or screws. Match the attachment style rather than guessing.
4. Measure the top and both sides of the opening. Write each length separately and note the seal’s profile, color, and width. Check the door-kit package to confirm it fits your measurements and surface.
5. Clean loose dirt from the door stop and threshold with a dry cloth. Before buying or removing material, close the door again and make sure it latches normally. A badly uneven gap points to an alignment problem rather than a simple worn seal.

When to ask for help

Ask for help if the door is warped, rubs the frame, will not latch, has rotten wood, or shows a large uneven gap. Those conditions need correction before new weatherstripping can seal properly.