Mould on Silicone: What to Know
That dark line on shower or sink silicone is living mould. Here’s how I handle it safely—and how you can help keep it from coming back.
Health & safety (short version)
- Mould can irritate eyes, skin, nose, throat, and lungs—especially for people with asthma or allergies.
- During removal I use PPE: gloves, eye protection, and an N95 respirator.
- For very large or hidden mould problems (behind walls, in drywall, or spreading beyond the caulk), professional remediation is recommended.
What I do for silicone mould
- Full removal of mould‑stained silicone (no skim‑coating).
- Clean & dry joints thoroughly (remove soap film; dry the area).
- Re‑caulk with sanitary, mould‑resistant silicone.
- Tool & cure and advise when you can use the area (typically ~24 hrs).
When we replace vs. try to clean
Surface staining can sometimes be lightened, but silicone is porous enough that mould roots often return. Replacing the bead is the lasting fix.
Your aftercare checklist
- Run the bath fan during showers and for ~20–30 minutes after.
- Wipe/squeegee joints after use; keep soap scum off the bead.
- Fix leaks quickly and keep indoor humidity near 30–50% if possible.
- Never mix cleaners (e.g., bleach + ammonia).
When to call a remediation pro
- Visible mould covers a large area (around or above ~3 m² in total).
- Musty odour with no visible source, or mould returns quickly after proper caulking.
- Leaks, water damage, or mould inside drywall/ceilings/substrates.