How To Remove And Replace Moldy Caulk In Bathroom Or Kitchen! DIY, by Fix This House on YouTube. 1 min.
- Video length
- 1 min
- Time to do it
- 1 hour plus 24 hours curing
- Difficulty
- Easy
- Steps
- 9
What you need
Steps
Slice through the old bead with a long cut knife, running the blade along the top edge where the caulk meets the wall and the bottom edge where it meets the tub or counter.
Lift the loose silicone away with a 10-in-1 scraper. Pull in one piece where you can instead of picking at it.
Brush on a caulk remover gel and leave it for the dwell time on the label, then scrape off the softened residue.
Treat the black staining with a bleach solution or white vinegar, scrub, rinse and let the joint dry completely. Silicone will not stick to a damp surface.
Run masking tape along both sides of the joint, leaving a gap the width of the bead you want, usually about 6mm.
Cut the tip of the silicone tube at a 45 degree angle, load it in the caulk gun and pierce the inner seal.
Push an even bead along the joint, keeping steady pressure. Fill the gap rather than smearing caulk across the tiles.
Smooth the bead with a wet finger or a silicone tool, then peel the masking tape off straight away while the caulk is still wet.
Leave the new seal for at least 24 hours before running water, and keep the room ventilated while it cures.
Tips and common mistakes
Never caulk over old moldy silicone, because the new bead will fail and the mold will grow back underneath.
Buy a kitchen and bath silicone labelled with a mold inhibitor, not a general purpose exterior sealant.
Keep the cut nozzle on the tube with a caulk saving cap so the leftover silicone stays usable for touch ups.
Wipe the joint with a dry cloth before taping, since dust stops the silicone from bonding.
Questions
How long before I can use the shower or sink?
Wait at least 24 hours, and longer if the room is cold or humid. Water on a half cured bead breaks the seal.
Can I just put new caulk over the old line?
No. New silicone will not bond to old silicone, and trapped moisture keeps the mold alive. Cut the old bead out first.
How do I stop the mold coming back?
Dry the walls after each shower and run the fan. Silicone with a mold inhibitor and a fully dry surface give it the best chance.
This guide was drafted from the video's details and general task knowledge. It has not been checked against the full video. Check the video and relevant product instructions before following a procedure. Report a correction.
