Re-caulk a bathtub
Remove the tired seal and leave a clean, watertight line around the tub.
Home · 1–2 hr + cure · Easy
Before you start
Ventilate and wear the protection specified for the cleaner and sealant. Never mix cleaners. Stop for soft backing, loose tiles, persistent mold or a moving tub—new caulk cannot repair those problems. Do not block the surround’s drainage openings.
Tools and materials
- Kitchen-and-bath silicone compatible with both surfaces; caulk gun
- Plastic removal and finishing tools, painter’s tape, cloths, compatible cleaner
- Gloves, eye protection, and a drain cover
Check the problem
Check whether the seal needs replacing
Cracks, peeling edges or mold embedded in the bead call for replacement. If the intact seal is only dirty, try compatible cleaning first. If water appears outside the tub when no water touches this seam, investigate the leak instead.
Check the joint and choose a sealant
Use a flexible bathroom sealant explicitly compatible with your tub and surround. Check allowable joint width and depth. A large gap, failed backing or repeated separation needs its cause corrected before this simple re-seal.
Steps
Protect the drain and clear the tub
Remove toiletries, cover the drain to catch debris and ventilate. Read the sealant’s preparation, tooling and water-ready times before starting; arrange to keep the bath out of use.
Lift out the old caulk
Start at a loose end with a plastic removal tool and pull away the bead. Work gently along both bonding faces. Use a surface-compatible caulk remover for stubborn residue, following its directions; do not scratch the finish or gouge behind the joint.
Clean the joint and let it dry
Remove every remaining film of old sealant, soap and cleaner from the bonding faces. Clean with a finish-compatible product, remove residue as directed, and let the seam dry thoroughly. Stop if the exposed joint reveals damp, soft or damaged backing.
Mask the edges and prepare the nozzle
If the tub maker requires loading the tub for sealing, follow its instructions while keeping the joint dry. Place tape along both sides, leaving the bonding faces exposed. Cut a small angled nozzle opening sized to the joint, open the inner seal if present, and load the gun.
Lay one continuous bead
Practice on scrap, then keep the nozzle at the joint and apply steady pressure while moving along it. Fill the seam so sealant contacts both faces, without leaving holes or piling on a wide mound. Release the gun pressure at each stop.
Tool the bead and remove the tape
Before a skin forms, draw a finishing tool along the seam to make a smooth, shallow concave fillet bonded to both sides. Remove excess from the tool as you go. Peel tape away while the sealant is still fresh; do not add soapy tooling liquid unless the sealant permits it.
Let it cure and inspect the seal
Keep the seam untouched and dry for the product’s stated water-ready time; allow its full cure before cleaning. Inspect for gaps or lifted edges before using the tub. After the first normal use, check again for separation or leakage.
A continuous bead adheres to both surfaces, with no holes, lifted edges or new leakage after normal use.
Tips
Start with a small nozzle opening
You can enlarge the opening if needed. An oversized cut makes a tidy narrow bead harder to control.
Fresh caulk needs bare bonding faces
A new layer over old silicone does not replace removal and cleaning.
Touch-dry is not water-ready
Use the label’s water-exposure and cure times, not the feel of the surface.