The Best Bathroom Sealant 2020

To prevent the build-up of mould and mildew within a wet environment in your home, you will require a bathroom sealant. They contain fungicides to prevent the growth of bacteria and provide a waterproof seal in areas of high condensation.

Best Bathroom Sealant

Anti-mould sealants for a bathroom is an essential part of getting it ready for use without having issues later down the line. Unlike chaulk, a bathroom sealant is waterproof, which protects walls and tiles from water damage.

The best bathroom sealant is the UniBond Silicone, which is specifically designed for warm and humid environments.

Application of a bathroom sealant is commonly achieved by using a gun. However, there are alternatives that can be applied via a squeeze tube. The sealant used doesn’t last forever and it may require resealing every few years.

Best Bathroom Sealant

Bathroom SealantColoursTube Size
UniBond Anti-MouldWhite or Ivory300 ml
Everflex 500White, Ivory or Clear295 ml
Dowsil 785 SanitaryWhite310 ml
Forever ClearWhite, Ivory, Grey or Clear80 or 310 ml
151 SiliconeClear50 ml

Areas that require sealing in the bathroom include tiles, shower trays, cubical doors, baths, sanitary fittings and much more. There are a range of sealant available but for rooms with high condensation, its vital that it is water resistant and includes fungicides to prevent bacteria build-up.

There a range of formulas to choose from but we highly recommend avoiding cheap alternatives and stick to the reputable brands. Below is a list of the best bathroom sealants that are easy to apply, water resistant and prevent the build-up of mould and mildew.

UniBond Bathroom Silicone Sealant

One of the most popular bathroom sealants available is by UniBond. It has been specifically designed for warm and humid environments such as bathrooms and shower rooms.

The UniBond formula provides a permanently flexible, waterproof and mould resistant sealant that is suitable for tiled areas, bathrooms, kitchens and worktops.

Features of the UniBond Bathroom Silicone Sealant include:

  • 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
  • Can be cleaned with any soap

Overall, it is the best bathroom silicone sealant that is designed specifically for warm and humid environments. The anti-mould formula is easy to use with a sealant gun and will provide a long lasting finish in the colour of your choice.
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Everflex 500 Bath & Sanitary Silicone

Another popular bathroom sealant is the Everflex 500, which provides a waterproof seal and is certified under the harmonized European standard (EN15651).

It is an anti-fungal formula designed for sealing baths, showers, sanitary fittings and tiles.

Features of the Everflex 500 Silicone include:

  • Available in clear, white or ivory
  • Permanently flexible
  • Fast curing formula
  • 295 ml tube
  • Designed to prevent mold build-up

This bathroom sealant is suitable for commercial and domestic applications and is a great alternative to the UniBond sealant. One drawback is that it doesn’t have the resealable cap like the UniBond but it does have the benefit of being the cheaper of the two.
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Dow Corning Dowsil Bathroom Sealant

The Dowsil bathroom sealant by Dow Corning is a popular option that focuses upon resisting bacteria and mould. The formula conforms to ISO 22196:2007 and ISO 11600-F-20LM industry standards and is suitable for both domestic and commercial applications.

Other features of the Dow Corning Dowsil include:

  • 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
  • Only available in white
  • 310 mm tube

The Dowsil formula is an excellent all-round bathroom sealant that is developed by the reputable Dow Corning brand. They have even gone as far as testing this product against bacteria growth, MRSA, E. Coli and Salmonella. Overall, Dow Corning Dowsil offers great value for money and will not disappoint.
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Forever Clear Anti-Mould Bathroom Sealant

Another popular bathroom sealant is the Forever Clear formula. It is available as a 295 ml tube for use with a gun or a smaller 80 mm squeeze tube for smaller jobs.

The Forever Clear is an anti-mold silicone mastic for areas of high humidity such as bathrooms and showers. It contains the brands patented “Mould Shield”, which actively prevents the growth of mildew, mould and bacteria.

Other features of the Forever Clear Silicone Sealant include:

  • Permanent waterproof and flexible seal
  • Certified under the harmonized European standard EN15651
  • Available in clear, white, grey or ivory
  • Touch dry in 15 minutes
  • Can be used indoor or outdoor

Overall, the Forever Clear bathroom sealant is a high quality silicone formula that can be used for almost every job that requires sealing.
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151 Bathroom Silicone Sealant

For smaller jobs that do not need a large tube, it may be cheaper and easier to use a squeeze tube such as the 151 silicone sealant. It is available in a 70g tube that includes an applicator nozzle and is easy to apply.

Other features of the 151 Bathroom Silicone Sealant include:

  • Fully waterproof formula
  • Available in a clear or white finish
  • No gun required for application
  • Screw on applicator nozzle
  • Perfect for smaller jobs

Overall, the 151 formula is a cheap bathroom sealant that is easy to apply and is designed for warm or humid environments. Whether you are sealing around a bathroom extractor fan or repairing tiles, it is a great option.
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Bathroom Sealant Buying Guide

Applying a bathroom sealant adds to the finishing touches in your bathroom. There are plenty of options to choose from but we highly recommend that you keep with the reputable brands for peace of mind.

The purpose of the sealant is to seal surfaces in areas of high humidity. They help prevent bacteria and fungal growth and ensure maximum hygiene within your bathroom.

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 for walls, ceiling and trim. It can also be painted over, which makes filling defects easier to blend in with the rest of the room. However, it is not the best option for bathrooms as it is not completely water resistant.

A silicone sealant is the better choice for a bathroom because it provides a waterproof barrier against moisture. However, due to the moisture repelling property of a silicone, it means it cannot be painted over.

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 dry to touch 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 bathrooms decor. The most common include clear, white, ivory and grey, which suit the majority of bathrooms.

The drawback of most sealants is that it cannot be painted over. However, if it is a major requirement, you can use an oil-based primer that can be painted over.

How To Use a Silicone Sealant

Application of a bathroom sealant is not as simply as spreading it on the surface and allowing it to dry. 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 use a seal surfaces within your bathroom.


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

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

Attaching to the Gun

If you are using a tube that requires a gun for application, you will need to correctly attach it to the gun. 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.


Once the surface has been prepared and the tube is loaded within the gun,  you are ready to begin sealing. You will 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.


In order to prevent mould and mildew build-up, you will 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.


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

All of the recommendations are developed by reputable brands and suited to a range of budgets with formulas that can be applied by a gun or squeeze tube.

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