Domakihub How to Reseal a Bath and Stop Leaks for Good
Strip out failed silicone, prep the surface properly, and lay a clean bead that lasts for years.
Reviewed by Domakihub home & decor pros · 2026-06-23 · 4 min read
A cracked or mouldy bath seal is one of the most common causes of water damage behind bathroom walls in Greek homes, holiday apartments, and hotel rooms — and it is also one of the cheapest fixes a homeowner can tackle themselves. The video above walks through the full process visually; this guide breaks it into clear, ordered steps with the product details and drying times you need to get a lasting result. Done correctly, a fresh silicone seal should stay clean and watertight for five years or more.
Why Bath Seals Fail
The joint between a bathtub and the surrounding tiles or wall panel is under constant movement. Every time the bath fills with water it flexes slightly under the load, stretching the silicone bead. Over months and years this micro-movement breaks the bond at the edges, letting moisture wick in behind the seal where it feeds black mould and, eventually, rots the substrate.
In Greece the combination of hard water, high humidity, and strong cleaning products accelerates degradation. Rental properties and hotel bathrooms are especially vulnerable because the bath is filled and emptied many times per day. Catching a failing seal early — before it lifts, cracks, or turns black all the way through — saves a much larger repair bill later.
Choosing the Right Silicone
Not all silicone sealants are equal. For a bathtub joint you need a sanitary-grade, mould-resistant silicone specifically rated for wet areas. Look for the words "fungicide" or "anti-mould" on the label. Neutral-cure silicone is safer for metals and natural stone; acetoxy-cure (the kind that smells of vinegar as it cures) is fine for ceramic tiles and acrylic baths but can corrode brass fittings or stain marble.
A 300 ml cartridge is enough for one bath perimeter. White is the standard colour for most Greek bathrooms, but sealant is also available in cream, grey, and a range of tile colours. If you are working in a rental property or hotel, opt for a product that explicitly states a 24-hour cure time so the room is back in service the next day.
How to Reseal a Bath: Step by Step
- 1
Remove all the old silicone
Use a plastic or wooden scraper (not a metal blade, which scratches acrylic baths) to lift the existing sealant away from the joint. Then apply a silicone remover gel, leave it for the time stated on the label — usually 30 to 60 minutes — and wipe away the softened residue with a cloth. Work carefully into the corners. Any fragment of old silicone left behind will prevent the new bead from bonding and the seal will fail again within weeks.
- 2
Clean and degrease the surfaces
Wipe down both the bath edge and the tile or wall surface with isopropyl alcohol (IPA) or a dedicated silicone surface cleaner. This removes soap scum, body oils, limescale residue, and any last traces of old sealant. Allow the surfaces to dry completely — in a damp Greek bathroom, leave at least 30 minutes with a window open or a fan running. The silicone will not adhere properly to a wet or greasy surface, no matter how well you apply it.
- 3
Fill the bath with water before you seal
This is the step most DIYers skip and later regret. Fill the bath to its normal working level before you apply the silicone. The weight of the water causes the tub to flex downward slightly, widening the joint to its maximum opening. If you seal with an empty bath, the joint closes when the bath is filled, stretching the fresh silicone immediately and eventually tearing it away from the wall.
- 4
Apply masking tape and gun the silicone
Run two strips of painter's tape along the joint — one on the tile side and one on the bath side — leaving a gap of about 6 to 8 mm between them. Load the cartridge into a skeleton gun, cut the nozzle at a 45-degree angle, and puncture the foil seal inside. Hold the gun at a consistent 45-degree angle and move along the joint in a single, smooth, unbroken pass. Maintain steady trigger pressure. Aim to slightly overfill the gap rather than underfill it.
- 5
Tool the bead and remove the tape
Wet your fingertip or a dedicated silicone finishing tool with soapy water to prevent sticking, then draw it along the bead in one smooth stroke to press the silicone firmly into the joint and create a concave profile. Remove both strips of masking tape immediately — before the silicone skins — pulling them back at a shallow angle. Leave the bath filled with water during the full cure period stated on the label (typically 24 hours). Do not use the bath before it has fully cured.
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FAQ
- How long does new bath silicone take to cure before I can use the bath?
- Most sanitary silicones are touch-dry in 30 to 60 minutes but require a full 24 hours to cure through before the bath can be used. Some specialist products cure in as little as 12 hours — check the label. Do not drain the water you used for the weighting step until the cure is complete; draining it early defeats the purpose of filling the bath before sealing.
- Can I apply new silicone directly over old silicone?
- No. Silicone will not bond to silicone. Applying a new bead over an existing one always fails — the new sealant sits on the surface rather than gripping the substrate, and it peels away within weeks. The old sealant must be removed completely, right back to clean tile and bath surface, before any new product is applied.
- My bath seal keeps going black with mould — is there anything I can do to prevent it?
- Black mould on silicone is a sign that moisture is sitting in and around the joint. Using a mould-resistant, fungicidal silicone slows regrowth significantly. Beyond the product choice, the key preventive measures are ventilation (open a window or run an extractor fan during and after every bath or shower), wiping the joint dry after use, and cleaning regularly with a diluted bleach solution or a specialist mould cleaner. In Greek holiday rentals it also helps to use a dehumidifier during unoccupied periods in winter.