Fix leaks, movement and moisture before resealing or regrouting
Wear gloves and eye protection. Stop if there is hidden water damage, persistent mould, structural movement or a safety-critical service penetration.
MOST LIKELY CAUSES
Start with these
Poor surface preparation
Soap, grease or old residue prevents proper adhesion.
Surface was damp
Silicone cannot bond reliably to wet surfaces.
Wrong sealant type
General-purpose products may fail in wet or high-movement areas.
Old sealant left behind
Fresh silicone does not bond well over cured silicone.
Symptom variations Match the exact failure pattern and location. ⌄
- Edges lifting
- Sealant pulls away in strips
- Water gets behind joint
- Sealant remains soft
- Failure returns quickly
Quick checks Simple checks before removing material. ⌄
- Check for leaks, damp or movement.
- Identify the existing sealant or grout type.
- Remove only failed material.
- Clean and dry the joint thoroughly.
- Choose a compatible flexible product.
Step 1 — Remove all failed silicone Remove failed material fully and use products suited to the joint, movement and moisture level. ⌄
Cut and peel away the old bead without damaging the surface.
Step 2 — Clean and dry the joint Remove failed material fully and use products suited to the joint, movement and moisture level. ⌄
Remove residue, soap and moisture completely.
Step 3 — Apply the correct sealant Remove failed material fully and use products suited to the joint, movement and moisture level. ⌄
Use a continuous bead, tool it neatly and allow full curing.
Common causes explained Why sealants, grout and joints fail. ⌄
Silicone peels when the surface was damp, dirty, contaminated, poorly prepared or the wrong sealant was used.
Advanced diagnostics Further checks for recurring failures. ⌄
- Check joint width and depth.
- Use backing rod where appropriate.
- Avoid applying over residual silicone.
- Check for movement or flexing.
- Confirm product compatibility with the surface.
Parts and materials needed Common materials linked to this repair. ⌄
- Sanitary silicone
- Silicone remover
- Masking tape
- Sealant gun
- Finishing tool
When to call a professional Conditions that should end basic DIY work. ⌄
- Water is leaking into walls or floors.
- The joint keeps opening because of movement.
- Mould or damp is widespread.
- An unvented cylinder, flue or fire-stopping joint is involved.
- Tiles or fittings are loose or unstable.
Frequently asked questions Common sealing and grouting questions. ⌄
Can new silicone be applied over old silicone?
No. Remove the old material and residue first for a reliable bond.
Should corners be grouted or sealed?
Changes of plane usually perform better with a suitable flexible sealant.