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How do you recaulk around exterior windows and doors?

Updated August 2026

1–2 hours · Easy DIY

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Recaulk an exterior opening the moment the bead cracks, shrinks, chalks, or lifts off the trim, which lands around every 5 to 10 years for silicone and every 2 to 5 for acrylic latex. Two or three openings take 1–2 hours and a $5–10 tube. Most of the job is removal, not application: the new bead only lasts if every scrap of the old one comes out and the joint underneath is clean and bone dry. Use exterior-grade silicone or polyurethane anywhere weather actually hits, and leave the painter's acrylic for interior trim.

What you need

Before you start: Anything above the first floor turns this into ladder work. Set the ladder at a 4:1 angle on firm ground, keep your hips between the rails instead of reaching sideways, and move it rather than stretching for the last 2 feet of a bead. Cutting old caulk overhead means a blade above your face, so wear eye protection and pull the knife toward the ground and away from your free hand. Look up before you place an aluminum ladder anywhere near the service drop or the meter.

Steps

  1. Walk the outside of the house and flag failures with tape: split beads, gaps that swallow a business card, caulk peeling off siding or brick, anything gone chalky. Check the top of each window first, since that is where water gets in.
  2. Pick your weather. Most exterior sealants want a surface between 40 and 90 degrees and 24 hours before rain. Silicone skins in about 30 minutes and cures fully in a day.
  3. Cut the old caulk out. Score both edges with the utility knife, then lever the bead free with a removal tool or stiff putty knife. Leaving old caulk in place is the single most common reason a recaulk fails inside a year.
  4. Scrub the joint, wipe it with denatured alcohol, and let it dry. Silicone bonds to nothing that is dusty, oily, damp, or already siliconized.
  5. Size the gap. Anything wider than a quarter inch or deeper than half an inch gets backer rod first, so the sealant forms an hourglass bead that stretches instead of a deep plug that tears.
  6. Cut the nozzle at a 45-degree angle, starting small, to a hole about as wide as the joint, and puncture the inner foil seal.
  7. Run the bead in one continuous pass, pushing the gun ahead of the nozzle so sealant is forced into the joint rather than smeared over it. Do a whole side of a window in one go, since every stop and start is a future leak.
  8. Tool the bead within 5 minutes using a wet fingertip or a caulk tool, pressing it against both surfaces, and pull the tape immediately while the sealant is still wet.
  9. Leave the drainage alone. Never caulk the weep holes along the bottom of a vinyl or aluminum window, or the underside of a window sill nose. Those are how water that gets in gets back out.

Or hire it out

A handyman charges $150–400 to recaulk the exterior of an average house, or $50–100 per opening on a small job, with a premium for second-story ladder work. Materials are $5–10 per tube and a house takes 3 to 6 tubes. The number that matters is what failure costs: water behind a window casing rots sheathing and framing, and that repair starts around $1,000 per opening.

Done. Now the part everyone skips: doing it again on schedule. Log it in OnOtto and the next reminder for exterior caulking sets itself.

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Frequently asked questions

Silicone, polyurethane, or acrylic latex?

Silicone is the default outdoors: flexible for 10 to 20 years and unbothered by UV, but it will not take paint. Polyurethane is tougher and paintable, the right pick where a joint moves or takes abuse, at $8–14 a tube and harder to tool. Siliconized acrylic latex is cheap, paintable, and lasts 2 to 5 years outside, which makes it an interior product with an exterior label. What caulk is compares them.

Can I run a fresh bead over the old one?

It looks fine for a season and then peels off in one long strip. New sealant bonds to the old bead rather than to the two surfaces of the joint, and cured silicone is one of the few things almost nothing sticks to. There is also no way to know what the old caulk is hiding underneath. Cutting it out adds 10 minutes per window and is the difference between a 10-year repair and a 10-month one.

Which gaps should I leave alone?

Anything that is an intentional drainage or ventilation path. That means window weep holes, the bottom edge of horizontal lap siding, the gap under a window sill nose, soffit and gable vents, and the bottom of the trim board over a brick ledge. Sealing those traps water inside the wall, which is worse than the draft you were chasing. Caulk the sides and tops of trim, not the bottoms.

Is this the same as recaulking a bathtub?

Same tool, different product and prep. A tub joint needs 100 percent silicone with a mildewcide, a fully dry and often water-filled tub, and a much smaller bead. Exterior joints move more with temperature, so they need backer rod and a thicker profile. What carries over is the removal discipline, which is where both jobs are won. Recaulking a bathtub covers the differences.

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