Despite often being hard to spot, sealants play a vital role in modern bathrooms. With the increasing popularity of wetrooms and fitted bathroom appliances...
Published 3rd January 2025

Despite often being hard to spot, sealants play a vital role in modern bathrooms. With the increasing popularity of wetrooms and fitted bathroom appliances, preventing water ingress has never been more crucial for installers. Here, Andy Cummins, Senior Product Manager at Geocel, takes a look at the solutions available as well as what installers should look out for in a quality product to ensure a quality finish.
Even though sealants may form a small part of a bathroom installation, selecting a poor-quality product can have a far-reaching impact, leading to water ingress, compromising bathroom fittings and furniture or simply causing an eye sore. All of which can have detrimental effects on professional reputation.
Low-quality silicone sealants are often bulked out with chemicals that evaporate as they cure. This evaporation can lead to a weak bond that will cause the sealant to shrink, crack and even lift entirely, providing a route for water ingress. DOWSIL™ 785 sanitary silicone, however, doesn’t contain any such compounds so you can get a seamless, crack free finish on a variety of non-porous surfaces and a permanent, water-tight bond.
The sustained humidity of a bathroom will also compromise a low-quality sealant, leading to black mould and mildew. To reduce the likelihood of mould growth and customer dissatisfaction, it is advisable to always select a high-quality sealant with a fungicide. Not only does DOWSIL™ 785+ incorporate a powerful fungicide, it also resists mildew growth and is bacteriostatic – ensuring your sanitary fittings stay protected against E.coli, MRSA and Salmonella.
Increasingly, clients are also requesting non-traditional materials in bathrooms such as granite and limestone. These porous surfaces, chosen for their striking aesthetic, are even more at risk of water ingress and due to their permeable nature, can be easily damaged by cheap sealants. DOWSIL™ 785N provides an excellent solution in these scenarios as it has a neutral cure – meaning it will provide excellent adhesion to challenging surfaces and won’t discharge any corrosive chemicals as it cures.
Finally, to guarantee longevity on a project, it is important to select a sealant that can absorb and withstand any knocks or movement. DOWSIL™ 785N is highly flexible once it has cured. With a joint movement capability of +/- 25% it will maintain a watertight seal even as the installation settles or day-to-day wear and tear results in fixture movement.
Selecting a hardwearing, specially formulated sealant that you can rely on is critical for providing customer satisfaction and peace of mind.
For more information about Geocel and DOSWIL™ products please click here or ask in your local Stax branch.
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