How to replace weatherstripping on a door

To replace weatherstripping on a door, find the gaps, peel off the old seal, clean the surface, and press or nail on a new seal that touches the door all the way around. In Arizona, a worn seal lets in hot air, fine dust and insects, and it makes your AC work harder. Most front and back doors take about 30 to 45 minutes.

Time: about 45 minutes. Skill: easy.

How do you know your weatherstripping is worn?

• You can see daylight around the closed door
• Dust collects on the floor just inside the door
• You feel warm air near the edges on a hot afternoon
• The rubber or foam is flat, cracked, brittle or missing

Try the paper test. Close the door on a strip of paper at several spots. If it slides out easily, the seal is weak there. At night, turn off the lights inside and have someone shine a flashlight along the edges from outside. Any light you see is a gap.

What kind of weatherstripping do you need?

• Adhesive foam tape is cheap and easy, but the sun and heat can shorten its life.
• Kerf-in or bulb seal presses into a groove cut into the door frame. It lasts longer.
• V-strip (tension seal) is a folded strip that fits in the gap and springs back.
• Door sweep attaches to the bottom of the door to close the gap above the threshold.

Measure the top and both sides, and the width of the door for a sweep. Buy a little extra. Check the width of the gap with a ruler to choose the right thickness of seal.

What do you need?

• New weatherstripping and a door sweep, if the bottom leaks
• A putty knife or scraper
• Rubbing alcohol or soapy water, and a rag
• Scissors or a utility knife
• A screwdriver and a drill for a sweep

How do you replace door weatherstripping?

1. Pull off the old seal. Peel it from the frame. For a kerf seal, pull it out of the groove.
2. Scrape off residue. Use the putty knife on old adhesive and dirt.
3. Clean the surface with rubbing alcohol or soapy water and let it dry fully. New adhesive will not stick to dust or damp.
4. Cut the new seal to length, one piece per side. Cut a little long and trim to fit.
5. Install the strip. For adhesive foam, peel and press it along the frame so the door compresses it lightly when it closes. For a kerf seal, push the fin into the groove. For V-strip, follow the package directions.
6. Replace the door sweep if the bottom leaks. Hold it against the bottom of the door, mark the holes, cut it to width and screw it on so it just brushes the threshold. It should not drag so hard that the door sticks.
7. Test the door. Close it. It should latch easily without slamming. Repeat the paper test and the flashlight test.

Arizona tip: work in the morning. Adhesive does not stick well to a door that is hot from the sun, and the heat can make it ooze.

Why does this matter in Arizona?

Gaps let in hot air, dust from haboobs and wind, and insects. Even small gaps can let in scorpions, which can squeeze through very thin openings. Sealing the door is one of the cheapest ways to help your AC.

When to call a pro

Call a pro if the door is warped, rotted, or sticks, the frame is damaged, the door does not latch, a sliding glass door is off its track, or the glass or window seals have failed. A seal cannot fix a door that does not fit. Here are local window and door companies in the directory, with phone numbers:

Check any contractor's license at roc.az.gov. If you are not sure, ask the helper.

Questions people ask

How often should you replace door weatherstripping?

There is no fixed schedule. In Arizona sun, adhesive foam may need replacing every year or two, while sturdier seals last longer. Replace it when you see gaps, cracks or flat spots.

Can you put new weatherstripping over old?

It is better to remove the old seal first. New material will not stick or seal well over old, dirty strips.

What is the difference between a door sweep and weatherstripping?

Weatherstripping seals the sides and top of the door against the frame. A door sweep seals the gap along the bottom, above the threshold.

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