The Best Bathroom Sealants For A Watertight & Fresh Finish

Seal the deal for a watertight bathroom: Our hand-picked selection of sealants ensure protection from water entry in high condensation and wet areas.
Tried & Tested: See Our Testing ↓
Written & Tested By: Richard Morgan | Updated:
Best Bathroom Sealant
Richard Morgan/DIY Works
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    Bathroom sealants provide a defence against water penetration in areas prone to high humidity or moisture, making them suitable for applications such as showers, baths and many other applications. Whether you are reapplying a sealant or installing new bathroom fittings, a water-tight seal is crucial to prevent water damage.

    Areas that often require sealing in the bathroom to ensure a watertight fit include the tiles, shower trays, cubical doors, bath and sanitary fittings. Although there is a range of sealants that you could use, it’s crucial that you use a formula that’s water-resistant and includes fungicides to prevent the build-up of mould, mildew and other bacteria.

    To help you choose the best sealant for your bathroom, our hand-picked selection features top-performing formulas chosen through our first-hand experience sealing various fittings, testing and thorough research.

    UniBond Anti-Mould Silicone Sealant
    Best Overall: UniBond Anti-Mould Silicone Sealant
    Everflex 500 Bath & Sanitary Silicone
    Best Value: Everflex 500 Bath & Sanitary Silicone
    Dow Corning Dowsil Bathroom Sealant
    Best All-Rounder: Dow Corning Dowsil Bathroom Sealant
    Everbuild Forever Clear Sealant
    Best Anti-Mould: Everbuild Forever Clear Sealant
    Gorilla Glue Mould Resistant Sealant
    Best Quality Finish: Gorilla Glue Mould Resistant Sealant
    151 Bathroom Silicone Sealant
    Best For Small Jobs: 151 Bathroom Silicone Sealant

    How The DIY Works Team Tests & Rates The Bathroom Sealants

    As we own several properties (rentals and Airbnb’s), we are often replacing damaged sealant or sealing new fittings in the bathroom.

    As shown in the photo below, we recently sealed a bath but we’ve also used sealants for showers, toilets, tiling, window frames, kitchen surfaces and so much more. Over the years, we’ve also tried and tested a whole range of sealants from some of the most reputable brands in the UK and there is certainly plenty to choose from.

    best sealant for showers

    Richard Morgan/DIY Works

    During our ongoing testing of bathroom sealants, we analyse their ease of application, quality and formulation (i.e. mould resistance).

    To display more of our experience with various bathroom sealants, we filmed and posted a video on our YouTube channel that shows us testing a bathroom sealant whilst demonstrating how to seal a bath.

    To keep up our commitment to reviewing and testing the latest bathroom sealants (for this article), we are continually testing out the latest offerings from top brands in the UK. This means that when we notice a brand has released a new and improved formula, we will attempt to buy it and put it to the test (where applicable).

    As well as our experience and testing of multiple sealants, we also based our recommendations on the latest research and several factors. Some of the factors that we took into consideration included the formulation, ease of application, colours and tube sizes available, drying time, ability to resist mould, awarded certifications, compatible surfaces, bulk buy options and value for money.

    The Best Bathroom Sealants

    At DIY Works, our content is 100% independent and we would never recommend a product that we wouldn't use ourselves (read our editorial standards and how we test products).

    1. Best Overall: UniBond Anti-Mould Silicone Sealant

    (How We Review →)

    By far one of the most popular bathroom sealants on the market is by the UniBond brand. According to the brand, it has been specifically designed for warm and humid environments and it’s perfect for use in showers or baths.

    In terms of its formulation, it’s a permanently flexible, waterproof and mould-resistant sealant that’s suitable for tiled areas, bathrooms, kitchens and worktops.

    • Long lasting with high adhesion
    • Touch dry in 20 minutes
    • Fully dry in 24 hours
    • Available in white or ivory
    • 300 ml tube with resealable cap
    • Easy to clean with soap
    • Relatively expensive when compared to the alternatives

    Although expensive, the UniBond formula is the best bathroom silicone sealant that’s designed specifically for warm and humid environments. The anti-mould formulation is very easy to use with a sealant gun and it provides a long-lasting finish that certainly won’t disappoint.

    2. Best Value: Everflex 500 Bath & Sanitary Silicone

    (How We Review →)

    Another popular bathroom sealant is the Everflex 500 Premium + and it’s the only sealant within this article that’s certified under the harmonized European standard (EN15651). In terms of its usage, it’s an anti-fungal formula that’s ideal for sealing showers, baths, sanitary fittings, tiles and so much more.

    • Available in clear, grey, ivory or sandstorm finishes
    • Permanently flexible
    • Fast curing formula
    • Prevents the build-up of mould
    • No resealable cap, which means it won't last once opened

    To conclude, the Everflex 500+ is a high-quality bathroom sealant that provides an excellent waterproof finish each and every time. The only drawback when compared to the UniBond alternative is the fact that it doesn’t have a resealable cap. However, it does benefit from being much cheaper and offering additional finishes to best suit your requirements.

    3. Best All-Rounder: Dow Corning Dowsil Bathroom Sealant

    (How We Review →)

    The Dowsil bathroom sealant by the Dow Corning brand is another great option to consider because it focuses on resisting bacteria and mould. The formula also conforms to the ISO 22196:2007 and ISO 11600-F-20LM industry standards and is suitable for both domestic and commercial applications too.

    • Fast curing and tack free in just one hour
    • Formula includes a fungicide to resist mould
    • Can be used in bathrooms, kitchens and sanitary fittings
    • Certified to the latest industry standards
    • Only available in white

    Overall, the Dowsil formula is an excellent all-round bathroom sealant that’s developed by the reputable Dow Corning brand. The brand has even gone as far as testing this product against bacteria growth, MRSA, E. Coli and Salmonella for complete peace of mind.

    4. Best Anti-Mould: Everbuild Forever Clear Sealant

    (How We Review →)

    The Everbuild Forever Clear is an anti-mould sealant that’s perfect for areas of high humidity such as bathrooms and showers. In terms of its formulation, it contains the brand’s patented “Mould Shield”, which actively prevents the growth of mildew and mould. Once applied correctly, the brand state that there should be no mould growth for up to 10 years.

    • Permanent waterproof and flexible seal
    • Available in clear, white, grey or ivory
    • Touch dry in 15 minutes
    • Available in a 295 ml or 80 ml tube
    • Can be used indoor or outdoor
    • Relatively expensive when compared to the alternatives

    Overall, the Everbuild Forever Clear is a high-quality silicone formula that can be used for almost every job that requires sealing. The choice of a smaller tube size is also a great bonus because it avoids any wastage of the larger tubes

    5. Best Quality Finish: Gorilla Glue Mould Resistant Sealant

    (How We Review →)

    Gorilla Glue is a highly reputable brand that’s well-known for its high performance formulas. This mould resistant sealant is a great example of that reputation and it’s perfect for shower trays, baths, sinks and so much more.

    In terms of using this sealant, it’s a fast drying formula that’s water-ready in just 30 minutes. It’s also able to provide a long lasting finish that the brand states won’t turn yellow, shrink or crack.

    • Versatile all-purpose sealant
    • Resists mould and mildew
    • Dries within 30 minutes
    • Lifetime guarantee
    • Suitable for indoor or outdoor use
    • Available in a tube or cartridge
    • Most expensive sealant within our roundup

    To conclude, the Gorilla Glue sealant is an excellent all-round option that combines performance with value for money. The fact that it comes with a lifetime guarantee is a clear indication of the high quality mould-resistant finish that it provides and it certainly won’t disappoint.

    6. Best For Small Jobs: 151 Bathroom Silicone Sealant

    (How We Review →)

    For smaller jobs that don’t require a large tube, it may be cheaper and easier to use a squeeze tube such as the 151 silicone sealant. It’s available in a 70 gram tube that includes an applicator nozzle and is very easy to apply.

    • Fully waterproof formula
    • Available in a clear or white finish
    • No gun required for application
    • Screw on applicator nozzle
    • Perfect for smaller jobs
    • Only available as a 70g tube

    Overall, the 151 formula is a cheap bathroom sealant that’s easy to apply and is designed for warm or humid environments. Whether you are sealing around a bathroom extractor fan or repairing tiles, it won’t disappoint.

    Bathroom Sealant Buying Guide

    A bathroom sealant not only makes fittings such as showers or baths waterproof but it also provides the finishing touch. To help you make an informed buying decision, we have produced the below guide regarding bathroom sealants.

    Caulk vs Silicone

    Caulk is a popular method of sealing walls, ceilings and pieces of trim and it can also be painted over, which makes it easier to blend in with the rest of the room. However, it’s not the best option for bathrooms because it’s not completely water resistant.

    A silicone sealant on the other hand is the better choice for a bathroom because it provides a waterproof barrier against moisture. However, due to the moisture-repelling property of silicone, it means that it can’t be painted over.

    Therefore, you’ll want to use bathroom paint elsewhere in the room and seal the areas around the bath, sink, shower and anywhere else with the sealant.

    Drying Time

    The majority of bathroom sealants require 24 hours to completely dry but there are many fast drying formulas available. For example, the UniBond sealant is touch dry in just 1 hour, which allows you to get on with other tasks.

    Colours Available

    Most manufacturers provide a range of different colours to match your bathroom’s décor. The most common include clear, white, ivory and grey because they suit the majority of bathrooms. However, if you need to paint over the sealant, you may be able to do this using an oil-based primer that can then be painted over.

    How To Use a Silicone Sealant

    Application of a bathroom sealant isn’t as simple as spreading it on the surface and allowing it to dry. This is because the surface needs to be fully prepared and the gun needs to be loaded with the sealant before you can begin. Below is a brief guide to the steps required to seal surfaces within your bathroom.

    1. Preparation

    Before you begin, the surface must be well-prepared and completely dry. The best option would be to completely remove the old sealant, which will strip back all the grease and dirt. Once removed, you can clean the surface that’s to be sealed and allow it to dry out.

    If you are worried that the surface isn’t completely clean, you can use a gel remover or even white spirit upon a damp cloth to wipe the surface.

    2. Attaching to the Sealant Gun

    If you are using a tube that requires a sealant gun for the application, you’ll need to correctly attach it. To do this, we recommend the following steps:

    1. Release the plunger by pressing the release at the back of the gun.
    2. Put the tube into the gun and push the plunger to the back.
    3. Cut the tip and push a nail through the hole to pierce the inner seal.
    4. Place the gun at a 45-degree angle along the joint width you want to seal.

    3. Sealing

    Once the surface has been prepared and the tube is loaded within the gun, you are ready to begin sealing. You’ll want to start in a corner and work across the length of the surface in a smooth movement.

    If you are planning to seal a bath, we advise that you half-fill it to prevent any movement once it has dried. After the sealant has completely dried, you can then empty the bath.


    To prevent mould and mildew, you’ll have to regularly clean the sealant. Soap and other residues can instigate bacteria growth upon the sealant but catching it before it begins to spread is highly advised. However, if you do notice the growth of mould, you can use one of the many mould removers available to quickly eliminate it from the surface.


    Adding the finishing touch to your bathroom with a quality sealant is highly recommended. Without using a sealant, you’ll leave areas exposed to moisture, which can then lead to water damage and bacteria growth.

    All of the recommendations listed above are developed by reputable brands and are suitable for a range of budgets. They also include sealants that can be applied by a gun or squeeze tube to best suit your requirements. However, if you need further information with regards to bathroom sealants, feel free to get in touch and we’ll try to provide our assistance where possible.

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