How to Weatherstrip an Exterior Door
Short answer: Close the door on a sheet of paper or look for daylight to find gaps, then replace worn weatherstripping on the jamb with a matching compression or kerf-in seal and add or adjust a door sweep at the bottom. The door should close with light resistance and no daylight showing.
- Difficulty
- Easy
- Time
- 1 to 2 hours
- Updated
- November 9, 2026
What is causing it?
Weatherstripping flattens, tears and pulls loose over the years. The bottom of the door is often the biggest leak, where a sweep or threshold seal has worn out. Sealing air leaks is one of the cheaper ways to cut heating and cooling loss.
Tools and materials
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Tools
- Utility knife or snipsCheck price on Amazon
- Tape measureCheck price on Amazon
- Screwdriver or drillCheck price on Amazon
- Putty knifeTo pry out old kerf sealsCheck price on Amazon
Materials
- Kerf-in foam weatherstrip (for slotted jambs)Bring a piece of the old seal to matchCheck price on Amazon
- Adhesive foam or V-strip weatherstripping (for flat jambs)Check price on Amazon
- Door sweepMeasure door widthCheck price on Amazon
- Rubbing alcohol and ragsTo clean surfaces for adhesiveCheck price on Amazon
How do you weatherstrip a door? Step by step
Find the leaks
On a bright day, close the door and look for daylight around the edges. Or close the door on a sheet of paper at several points; if it slides out with no drag, the seal there is not contacting.
Identify the type
Many modern doors use kerf-in seals pressed into a slot in the jamb. Older or simpler doors use adhesive foam, V-strip or nailed felt.
Remove the old seal
Pull kerf seals straight out of the slot. Scrape off adhesive strips and clean the surface with rubbing alcohol.
Install the new weatherstripping
Cut pieces to length for the hinge side, top and latch side. Press kerf seals into the slot starting at a corner, or apply adhesive strips to a clean, dry surface. The seal should compress when the door closes but still let the door open and latch freely.
Seal the bottom
Replace the sweep or the threshold insert. Screw-on sweeps have slotted holes: set the sweep so it lightly touches the threshold when closed, then tighten.
Test
The door should latch with slight resistance. If it is hard to close, the seal is too thick.
Safety notes
- Do not seal so tightly that the door will not latch; an exterior door must close and lock reliably.
- In homes with fuel-burning appliances, good air sealing makes working carbon monoxide alarms and proper venting even more important.
When should you call a pro?
- The door is warped and no seal will close the gap.
- The threshold or bottom of the frame is rotted.
- You are planning whole-house air sealing; an energy audit can find bigger leaks.
Frequently asked questions
Which weatherstripping lasts longest?
Durability varies by material. Kerf-in and vinyl or silicone bulb seals generally outlast adhesive foam, which is cheap and easy but wears faster.
How do I know if the door sweep is right?
It should brush the threshold lightly when the door is closed. Too tight and the door drags; too loose and air gets under.
Does weatherstripping really save energy?
The U.S. Department of Energy's Energy Saver guide lists caulking, sealing and weatherstripping openings to the outside among the quickest ways to cut heating and cooling costs.
Sources
Steps are based on these manufacturer and safety references. Your product's own manual comes first.