Recaulk a bathtub or shower
Once mold has grown into tub caulk, no cleaner will bring it back, and gaps in old caulk let water get behind the tile. Pulling it out and running a fresh bead takes an afternoon, plus time for the new caulk to cure. Most of that time is prep. Running the bead takes about ten minutes; getting every scrap of the old caulk off is what makes the new one last.
How to get a clean line
Neat caulk comes down to painter's tape more than a steady hand. Tape both sides of the joint, run a bead, smooth it, and pull the tape while it's still wet. You get a straight, clean line without having to be good at it.
The other thing that matters is getting every bit of the old caulk out. New silicone sticks poorly to old caulk, so this is the step that decides whether the job lasts.
Why caulk fails
Mildew grows into the caulk and behind it, where cleaners can't reach.
Tubs flex a little when you step in. Over the years, that pulls the caulk loose on one side.
Latex or acrylic caulk breaks down faster in wet areas than 100% silicone.
New caulk doesn't bond to old caulk, so it peels.
| Spot | Use |
|---|---|
| Tub and shower seams | 100% silicone, labeled for kitchen and bath |
| Around the outside of a toilet base | Silicone, leaving a gap at the back so leaks show |
| Painted trim and baseboard | Paintable acrylic latex caulk |
| Outdoor windows and siding | Exterior-grade sealant, labeled for outdoor use |
Remove the old caulk, then run a new bead
- Remove all the old caulkScrape it out with a plastic caulk tool or a razor scraper. Get every bit, including the thin film on the tile.
- Kill the mildew and let it dryWipe the joint with a mildew remover or a mild bleach solution (gloves on, fan running, and never mix bleach with other cleaners), rinse well, then wipe with rubbing alcohol. Let it dry several hours, ideally overnight.
- Fill the tub with waterOn many tubs, especially acrylic and fiberglass, a full tub settles a little lower, the way it does when you're in it. Caulking it that way keeps the bead from cracking later. Leave the water in until the caulk has set, at least a few hours.
- Tape both sides of the jointRun painter's tape along the tub and along the tile or wall, leaving a gap about the width of the bead you want. The tape gives you a straight edge and catches the mess.
- Run a steady beadCut the tip small and at an angle. Hold the gun at about 45 degrees and push a steady bead along the joint, in one long pass where you can reach, without stopping and starting.
- Smooth it in one passWet a fingertip or a caulk tool (soapy water works well for silicone) and draw it along the bead once, pressing lightly so the caulk fills the joint. Don't go back over it.
- Pull the tape right awayPull it at an angle away from the bead while the caulk is still wet. Leave the shower unused for 24 hours, or as long as the tube says. The finished bead should be smooth and continuous, with no gaps where you can see the joint.
Watch it done
- The bead is smooth and continuous with no gaps
- No old caulk or film left along the edges
- Clean, straight lines where the tape came off
- The caulk holds without peeling in the weeks after
Peeling within weeks? Strip it, clean with alcohol, and dry overnight.
If it doesn't hold
If new caulk peels within weeks, the surface wasn't completely clean or dry. Take it out, wipe with rubbing alcohol, and let it dry overnight before trying again.
If mold comes back quickly, the bathroom needs better ventilation. Run the fan during showers and for about 20 minutes after.
What a pro typically charges (a rough estimate; prices vary by area): A handyman typically charges $150–$300 to recaulk a tub or shower.
Find a handyman near you