Around the House · Doors

How to weatherstrip a door

If you can see daylight around a closed door, you're heating or cooling the outside. Weatherstripping is the cheapest energy upgrade in the house — usually under $30 and an afternoon's work.

Job time 1 – 2 hrs per door

Skill level Beginner

Job cost $15 – $50

The Honest Read

What this job actually involves

An exterior door has four seal points: the top jamb, both side jambs, and the bottom (threshold + sweep). Air leaks at any of them — but the bottom is the worst offender because gravity pulls cold air in across the floor.

Most weatherstripping problems are just compressed, torn, or missing material. A 10-year-old door has 10-year-old foam seals, and foam doesn't last forever. Replace, don't repair.

Adjustable thresholds are an under-known feature. If your threshold has plug-covered screws on top, you can raise it up 1/4″ or so to close the gap under the door without buying anything.

What you need

Tools & materials

Shop the supply side here. The big-ticket stuff and the brand-restricted items, we'll point you local further down.

Tools

Tape measure
Utility knife
Screwdriver (Phillips and flathead)
Hammer
Pencil
Hacksaw (for cutting door sweeps to length)

Materials

Adhesive-backed foam or rubber weatherstripping (jamb)
Door sweep (bottom of door — pick the style that matches your gap)
V-strip or kerf-in weatherstripping (for fitted jambs)
Door shoe or door bottom (replaces a worn-out built-in sweep)

The Steps

Find the leaks and seal them

Find every leak

Close the door. On a windy day, run the back of your hand around the entire perimeter — you'll feel the cold spots. No wind? Light a stick of incense and trace the perimeter — the smoke will pull toward the leak. Mark each leak with a piece of tape.

Check the threshold first

Look at the threshold from above — if there are plug covers hiding screws, you have an adjustable threshold. Pop the covers, turn screws clockwise to raise (1/4 turn at a time, all of them evenly). Close the door, check the seal. Stop when the door closes firmly but isn't fighting you on the latch.

Replace the door sweep

Most door sweeps screw to the inside bottom of the door. Measure the width of your door, cut a new sweep to length with a hacksaw. Screw it in with the rubber flange just kissing the threshold — too tight wears it out fast, too loose leaks.

Strip the jambs

Pry off the old weatherstripping. If it's kerf-in style (slides into a slot in the jamb), pull it out and slide new strip in. If it's adhesive foam, scrape off the old residue with a putty knife and isopropyl alcohol, then apply new strip — door side, top to bottom, no gaps at corners.

Test the seal

Close the door and try the dollar bill test: stick a dollar bill in the gap and close the door on it. Try to pull it out. It should drag. If it pulls free easily, the seal isn't compressing enough. If you can't get the dollar in at all, the seal is too thick — the door won't fully close, latch wear becomes a problem.

Final pass with a thermal scan or candle

Once everything's installed, do another walk-around. The wind / incense / candle flame test should now show nothing moving. If you still have a leak, it's probably the door itself (worn or warped), the latch (door not pulled tight), or the threshold gap that no sweep can close.

Try local first · We'll wait

Weatherstripping at a local hardware store

Door seal hardware is one of those areas where the local store wins every time — there are dozens of profiles, sizes, and styles, and you really need to match what you have.

Bring the old strip in for a direct match — they almost always have it
Door sweeps in every height and style (rubber flap, brush, vinyl bulb)
Adjustable kerf-in seals you can't always find online
Threshold gaskets and corner pads for the gap that no sweep closes
Real expert advice on whether the door needs new seal or a new threshold or just adjustment

Find a local hardware store →

When to call a pro

Call a handyman or door installer if: the door has visibly warped or sagged (rehang or replace, not seal); the threshold itself is rotted or broken; the door rubs the frame so badly you've planed it more than 1/4″; or you can see daylight at the corners with the door closed (frame is out of square — that's a structural fix). Otherwise this is a weekend job worth doing yourself.

Keep going

Related project guides

Around the House

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