The Best Way to Remove and Replace Moldy Caulk (The Handyman Way), by Handy Leo on YouTube. 12 min 20 s.
- Video length
- 12 min 20 s
- Time to do it
- 2 hours
- Difficulty
- Easy
- Steps
- 9
What you need
Steps
Cut along both edges of the old bead with a sharp scraper or utility knife. Keep the blade flat so you do not gouge the tub or tiles.
Pull the caulk out in long strips where you can. Work slowly and keep the strip together instead of snapping it into small pieces.
Scrape off any film left on the tiles and tub. A plastic scraper is safer than metal on acrylic surfaces.
Apply a silicone remover to the stubborn film you cannot scrape away. Leave it on for the time stated on the bottle, then wipe it off.
Clean the joint with rubbing alcohol and a clean rag. This removes soap scum and grease so the new silicone can bond.
Let the joint dry completely. Wait at least a few hours, or overnight if the room is damp, because silicone will not stick to a wet surface.
Run a bead of silicone along the joint with a caulking gun. Keep the nozzle at a steady angle and push the bead forward.
Smooth the bead with a caulk tool instead of your finger. Wipe the tool clean between passes.
Leave the new bead to cure for 24 hours before you use the shower or bath. Check the tube for the exact cure time.
Tips and common mistakes
Mask both sides of the joint with painter's tape before caulking for a clean edge, then peel it off while the silicone is still wet.
Never caulk over old moldy silicone. The new bead will fail in the same place.
Keep the bathroom ventilated while you work with silicone remover and caulk.
Fill the tub with water before caulking if it flexes, then drain after curing so the bead sets in its loaded position.
Questions
Why does my new caulk go black so fast?
Mold usually grows behind the bead because the joint was damp or dirty when you sealed it. Dry and clean the gap fully before applying new silicone.
Can I use bleach to clean moldy caulk instead of replacing it?
Bleach only treats the surface. If the mold is behind the bead, the caulk has to come out and the joint needs to be cleaned and dried.
How long before I can shower after caulking?
Most silicone needs about 24 hours to cure. Check the tube, since some fast-cure products need less time.
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.
