Symptoms
- Caulk lifts away from the tub edge when touched
- Visible gap between caulk and tile or tub
- Caulk looks brittle, cracked, or discolored
- Water seems to seep behind the tub edge
Likely causes
- CommonNormal aging and loss of adhesionSilicone and acrylic caulk lose elasticity and bond strength after several years.
- CommonMovement between the tub and wall/floorTubs flex slightly with weight and temperature changes, which stresses the caulk bond over time.
- PossiblePoor surface prep during original applicationCaulk applied over soap residue, moisture, or old caulk often fails prematurely.
- Less commonWrong type of caulk used originallyNon-flexible or non-waterproof caulk products fail faster in a wet environment.
What to do
- Use a utility knife to cut and peel away all of the old, failing caulk along the joint.
- Scrape off any remaining residue with a plastic putty knife, being careful not to scratch the tub surface.
- Clean the joint thoroughly with rubbing alcohol and let it dry completely, ideally for several hours or overnight.
- Apply painter's tape along both sides of the joint to get clean, straight lines.
- Run a continuous, steady bead of 100% silicone caulk along the gap using a caulk gun.
- Smooth the bead immediately with a wet finger or caulk-smoothing tool, then remove the tape before the caulk skins over.
- Avoid using the tub or shower for at least 24 hours to let the caulk cure fully.
Tools and parts
- Utility knife
- Plastic putty knife
- Caulk gun
- Painter's tape
100% silicone caulkSearch: “100% silicone waterproof caulk tub and tile”
When to call a pro
Call a contractor if you find soft or damaged material behind the tub edge once old caulk is removed, since that suggests water has already gotten in.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.