Why does bathtub caulk keep cracking over and over?
Bathtub caulk repeatedly cracks shortly after application, which traps mildew underneath and forces people to redo the job every few weeks. This endless cycle wastes time and money while failing to maintain a proper waterproof seal around the tub.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1Using more expensive brands
- 2Switching to 100% silicone caulk
- 3recaulking frequently
- 4filling the tub with water while caulking
- 5using alcohol to clean the area
- 6using 100% silicone or stretchy caulk
- 7using a dehumidifier
- 8cleaning with hydrogen peroxide and dawn powerwash
- 9cleaning the surface with alcohol before applying caulk
In their words
Unedited, most upvoted first, each linked to the thread it came from.
“I have recaulked this tub *four times* in the past year or so, and it cracks almost immediately, then grows mildew underneath.”source ↗
“I really don't have time to recaulk every few weeks, and I don't have money to hire someone.”source ↗
“I've sealed my tub with caulk I don't even know how many times now. And it always ends up with the caulk just cracking.”source ↗
“we cannot seem to get ANY caulking to stick and hold, including silicone, and caulks made specifically for showers/tubs. after 6ish months, it starts to just peel off. we ensure the shower is dry, clean with alcohol first, and it still fails after a period of time.”source ↗
“ugh that pink slime is relentless, i swear it has a personal vendetta against white grout. for the caulking peeling off like that it's usually because the gap between the tile and the tub is too deep, so it can't grip both sides properly. stuff some foam backer rod in there first and then try the silicone again, that should give it something to actually hold onto.”source ↗
Where this came up
People with this problem also raised
- 4Second-floor bathtub is cracking and flexing with no backup bathroom
- 6Should I put caulk over missing grout in shower corners?
- 8Do I need to caulk my new shower or was it left unfinished?
- 10How to get dark buildup off bathtub caulk
- 4Gaps between shower wall and drywall
- 3How to fill a 4-inch gap under an acrylic tub