Quick answerFind drafts with the candle test on a windy day, measure the gaps, then apply the right seal — adhesive foam tape for small even gaps, V-strip for the sides, and a door sweep for the bottom. Clean the surface first so the adhesive actually holds.
What you'll need
- Weatherstripping of the right type for your gaps ($8–$20 per door)
- Door sweep for the bottom gap ($8–$15)
- Tape measure
- Scissors or utility knife
- Rubbing alcohol and rag (for cleaning the frame)
- Candle, lighter, or incense stick (for the draft test)
Step-by-step
- Find the drafts. On a windy day, hold a lit candle or incense stick slowly around the closed door's edges. Where the flame flickers or the smoke streams sideways, air is getting through. Mark those spots with painter's tape.
- Measure the gaps. Close the door and check the gap at the top, sides, and bottom with a tape measure. Gaps under 1/8 inch want V-strip; 1/8 to 1/4 inch take foam tape; bigger gaps need tubular rubber or a kerf-in seal. The bottom usually needs a sweep regardless.
- Clean the frame. Wipe the door frame where the stripping will stick with rubbing alcohol and let it dry. Adhesive weatherstripping on a dusty or greasy frame peels off within weeks — this two-minute step is what makes it last years.
- Apply the side and top seals. Start at the top: cut foam tape or V-strip to length, peel the backing a few inches at a time, and press firmly into place. Work down the sides the same way. Don't stretch foam tape as you apply it — stretched foam shrinks back and leaves gaps at the ends.
- Fit the door sweep. Measure the door width, cut the sweep to fit, and screw or slide it onto the bottom of the door. It should just brush the floor or threshold — too tight and the door drags, too loose and drafts pour under.
- Close and check. Shut the door firmly. It should close with slightly more resistance than before but still latch easily. If you have to slam it, the stripping is too thick — step down a size.
- Redo the candle test. Check your marked spots again. Any remaining flicker means a spot you missed or a seal that isn't compressing — adjust before you call it done.
<div class="safety"> <strong>🛑 Stop and call a pro if:</strong> <ul> <li>The door frame itself is rotted, warped, or pulling away from the wall — no amount of stripping seals a failed frame.</li> <li>There's a large uneven gap because the house has settled and the door is visibly out of square — that needs rehanging.</li> <li>You feel drafts around the whole frame where it meets the wall, which means missing insulation behind the trim, not a door-seal problem.</li> <li>It's a fire door in a multi-unit building — use only fire-rated seals and check building regulations first.</li> </ul> </div>
DIY vs pro cost
| Option | Typical cost |
|---|---|
| DIY | $10–$25 |
| Pro visit | $100–$200 |
Printable checklist
- [ ] Candle test on a windy day; mark draft spots
- [ ] Measure gaps at top, sides, and bottom
- [ ] Buy the right type for each gap size
- [ ] Clean frame with rubbing alcohol
- [ ] Apply top and side seals without stretching
- [ ] Fit door sweep to just brush the floor
- [ ] Check door still latches easily
- [ ] Re-test with candle; fix any misses
Related guides
- How to Patch a Drywall Hole (Small to Large)
- How to Fix a Squeaky Door Hinge in 5 Minutes (No Removal)
- How to Fix Squeaky Floors (From Above and Below)
Frequently asked questions
How much will weatherstripping actually save on heating bills?
It varies a lot by climate and how drafty the door was, but sealing a badly leaking exterior door makes a noticeable difference to comfort immediately — no more cold draught across the floor. For the $15 it costs, it's the cheapest comfort upgrade in the house.
Foam tape, V-strip, or rubber — which should I buy?
Match it to the gap: V-strip (tension seal) for narrow, even gaps on the sides; foam tape for slightly larger or uneven gaps; tubular rubber for big gaps. When in doubt, V-strip on the sides plus a door sweep covers most doors well.
My door sweep scrapes the floor — is that normal?
It should lightly brush, not drag. If it's gouging the floor or making the door hard to open, trim it or adjust it up a fraction. A sweep that fights you every time will get ripped off within a month.
How long does weatherstripping last?
Foam tape typically lasts 1–3 years before it compresses flat; V-strip and silicone tubular seals last 5+ years. Check every autumn — if the foam stays flat when you press it instead of springing back, it's done.
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