Shower & Bath Sealants
(6 Products)Shower and bath sealants are engineered to handle everything your bathroom throws at them, from the constant barrage of water to daily soap suds. They work by protecting the vulnerable joints around your bath, shower tray, and basin, areas where constant moisture could otherwise lead to serious damage. Unlike standard sealants, they are infused with powerful anti-fungal agents to prevent the build-up of mould and mildew, promising a clean and long-lasting seal.
What Are Shower & Bath Sealants?
A bath and shower sealant is a hardworking compound with two crucial jobs. First, it forms a flexible, waterproof barrier in the joints around your fixtures - like baths and showers - to stop water from causing structural damage from damp and rot.
Secondly, and just as importantly, it contains powerful anti-fungal ingredients to actively fight off black mould. These agents are slowly released throughout the sealant's life, actively preventing mould and mildew spores from taking root and growing on the surface.
This is why a high-quality sanitary sealant can remain clean and white for years, while a general-purpose product might show black mould spots within months.
The quality and longevity of this protection is a key factor tested under the BS EN 15651-3 standard for sanitary sealants.
BS EN 15651-3 Explained
Any sealant specified for sanitary use within the UK and Europe should be classified under BS EN 15651-3: Sealants for Sanitary Joints (Type S). This is a harmonised standard under the Construction Products Regulation, and CE/UKCA marking against it is mandatory.
Products marked EN 15651-S-S1 have been tested for performance in sanitary applications (S) and have a specific movement capability (S1). This also verifies their resistance to mould growth and water resistance.
Benefits
- 100% Waterproof: Creates a completely impermeable barrier against water.
- Powerful Mould Resistance: Bathrooms are a prime breeding ground for mould. Sanitary sealants contain a potent, integrated fungicide (or biocide) that actively inhibits the growth of mould, mildew, and bacteria on the sealant surface.
- Flexibility: Joints in a bathroom are not static. Shower and bath sealants have good Movement Accommodation Factor (MAF) to handle the minor movements caused by temperature changes and a bath or shower tray flexing under weight. This prevents the sealant from cracking or pulling away from the joint.
- Strong Adhesion: Forms a durable bond to a range of common, non-porous bathroom surfaces, including ceramic and porcelain tiles, glass, enamelled steel, and modern acrylic or composite materials.
Troubleshooting Common Sealant Failures
Even with a quality product, sealant application can sometimes go wrong. Understanding why a sealant has failed is key to preventing it from happening again.
- Problem: The Sealant is Peeling Away from the Wall or Fixture.
- Cause: This is an Adhesive Failure. It almost always means the surface was not prepared correctly. Trace amounts of soap scum, grease, dust, or moisture were likely left in the joint, preventing the sealant from forming a strong bond with the substrate.
- Solution: The sealant must be completely removed. The joint needs to be mechanically scraped and then chemically cleaned with a solvent like isopropyl alcohol to create a perfectly clean, dry, and sound surface before re-applying.
- Problem: The Sealant has Split Down the Middle.
- Cause: This is a Cohesive Failure. It indicates the movement in the joint was greater than the sealant's flexibility (its Movement Accommodation Factor). This can happen if a rigid, low-flexibility sealant was used in a high-movement joint (like around a lightweight acrylic bath), or if the sealant was applied too thinly.
- Solution: Remove the old sealant and choose a new one with a higher flexibility or movement accommodation. Ensure the new bead of sealant has sufficient depth and width to handle the expected movement.
- Problem: Black Mould has Appeared, Even on a "Mould-Resistant" Sealant.
- Cause: While sanitary sealants contain powerful fungicides, this resistance is not infinite. The fungicide's effectiveness can be diminished by two main factors:
- Harsh Cleaning Chemicals: Regular use of bleach or abrasive cleaners can break down the fungicide in the sealant's surface layer, allowing mould to take hold.
- Soap Scum Build-up: Mould feeds on soap residue and body oils. If a layer of scum is allowed to build up on top of the sealant, mould can grow on that layer, even if the sealant itself is still resistant.
- Solution: Clean sealants regularly with a pH-neutral bathroom cleaner, not harsh bleach. Ensure the area is well-ventilated to allow it to dry out, and rinse away soap suds after every use.
- Cause: While sanitary sealants contain powerful fungicides, this resistance is not infinite. The fungicide's effectiveness can be diminished by two main factors:
Frequently Asked Shower & Bath Sealants Questions
What Colour Are Shower & Bath Sealants?
Typically, standard silicone sealant will be either white or clear, although there are a variety of other colours on offer from grey-white to sandstone, ensuring you can complement the colour scheme of your bathroom.
Should I Really Fill The Bath With Water Before Sealing It?
Yes, this is a crucial professional tip, especially for acrylic or thin steel baths. These baths flex and sink slightly when filled with the weight of water and a person.
By filling the bath before applying the sealant, you are sealing the joint at its widest point. This ensures that when the bath is empty, the sealant is compressed, and when it's full again, it doesn't get over-stretched and pull away from the wall.
Does Using Bleach Or Mould-And-Mildew Spray On My Sealant Damage It?
Yes, regular use of harsh cleaning chemicals like bleach can damage your sealant over time. These chemicals can break down the integrated fungicide on the surface layer, making it more susceptible to mould growth in the future.
It's better to clean your sealant regularly with a pH-neutral bathroom cleaner and rinse away soap scum after each shower, as this is what mould feeds on.
Should I Seal The Base Of A Freestanding Bath To The Floor?
Generally, no. A freestanding bath is designed to be an object in the room, and a sealant bead around the base can look unsightly and trap dirt. The primary waterproofing should be the floor itself (e.g., tiled with sealed grout).
Leaving the base unsealed allows you to clean under the bath and ensures that any water splashed on the floor can be wiped up without being trapped against the tub's base.
