Every 1 to 2 years
Inspect it once a year and re-caulk showers and tubs every one to two years, since they take constant moisture and temperature swings. Do not wait for the interval if you see cracking, peeling, shrinkage, or mold; that is the signal to redo it now.
Caulk is the thin waterproof seam between your shower and the wall behind it, and it is under constant attack from moisture and movement. When it cracks or pulls away, water goes straight into the wall, where it quietly rots framing and grows mold long before you see a problem in the room.
The job itself is satisfying and cheap. The one rule that separates a bead that lasts two years from one that fails in two months is removing every trace of the old caulk first and starting on a bone-dry surface.
How to do it
- Score both edges of the old caulk with a utility knife and pull it out in strips, using a caulk-remover gel on stubborn silicone. Getting all of it out is the step that determines whether the new bead lasts.
- Scrape off any residue with a plastic scraper and check the corners under bright light.
- Clean the bare joint with isopropyl alcohol or a mild degreaser to remove soap scum and oils, and treat any visible mold before you go on.
- Let the surface dry completely, at least 30 minutes, longer if it feels cool or damp.
- Run painter's tape along both sides of the joint for clean edges.
- Cut the nozzle of a 100 percent silicone tube at a 45-degree angle, slightly narrower than the joint, and push, do not drag, a steady bead into the gap.
- Smooth the bead in one or two passes with a wet, soapy fingertip to form a concave, water-shedding profile.
- Pull the tape while the caulk is still wet, then let it cure fully before using the shower, usually 24 hours or more per the label.
Common mistakes
- Caulking over the old bead. The new layer fails along the same lines, often within a season.
- Working on a damp surface. Trapped moisture breaks the bond and feeds mold.
- Peeling the tape after the caulk has skinned over, which tears a ragged edge instead of a clean line.
This is exactly the kind of thing that is easy to know and easy to forget. Adulting can put it on a cadence so it surfaces when it is next due, instead of when something goes wrong. Free to start.
Sources
Questions people ask
- Why does shower caulk fail so much faster than window caulk?
- It lives in constant moisture and repeated temperature swings. Exterior window caulk in good silicone can last five to ten years; a shower is a far harsher environment, so one to two years is realistic.
- What happens if I just leave the cracked caulk?
- Water gets behind the tile and into the wall framing, which leads to rot and mold that cost far more to fix than a tube of caulk and an afternoon.