Weatherstripping flattens, tears and hardens over time. Most of it lasts five to ten years. When it goes, you feel cold air at your ankles, hear more street noise, and see light at the corners at night.
Find the leaks
- At night, have someone shine a flashlight around the edges from outside while you look from inside.
- On a windy day, hold a lit incense stick near the frame; the smoke shows where air moves.
- Close the door on a strip of paper. If it slides out easily anywhere, the seal is weak there.
Pick the right type
Kerf-in (compression foam or bulb)
Has a fin that presses into a thin slot (the kerf) in the door stop. Common on doors from the last 30 years. Durable and easy to replace.
Adhesive foam tape
Cheap and easy, but wears out fast on a door that is used daily. Best for doors without a kerf, or as a stopgap.
V-strip (tension seal)
A folded strip of vinyl or metal that springs open to seal the gap along the side of the door. Good for older wood doors with no kerf.
Replacing kerf-in weatherstripping
Pull the old strip
Grip one end and pull steadily. It should come out of the slot in one piece.
Clean the slot
Run a putty knife or screwdriver tip along the kerf to clear dirt and paint.
Cut to length
Do the hinge side and latch side first, then the head (top). Leave each piece a quarter inch long so the corners compress tightly.
Press it in
Start at a corner and push the fin into the slot with your thumbs or a plastic roller. Do not stretch it.
Test
Close the door. It should latch with a light push and the strip should compress evenly.
The bottom of the door
Gaps at the bottom are sealed by a door sweep on the door, a threshold on the floor, or both.
- Sweeps screw or slide onto the door bottom. Replace one that has torn or curled.
- Adjustable thresholds have screws under caps along the top. Turn them counterclockwise to raise the threshold until a dollar bill drags when pulled out from under the closed door.
- Door shoes wrap the bottom of the door and slide into a channel. Match the profile when replacing.
Common questions
How much does weatherstripping save?
It depends on the house, but sealing air leaks around doors and windows is one of the cheapest efficiency upgrades there is, and the comfort difference is immediate.
Can I weatherstrip a sliding door?
Yes, but sliders use pile or fin seals in channels specific to the brand. Note the brand and model before shopping.
Our guides are general information for typical homes. Codes, permits and conditions vary, so check local rules, and leave gas, main electrical panel and structural work to a licensed professional.
