Professional Construction Products

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Waterproof Sealant

Waterproof Sealant Adhesive: Adiseal Seals & Bonds in Wet or Dry

Adiseal waterproof sealant adhesive provides a water tight seal instantly in dry, damp, or wet conditions. It provides a strong, flexible, water resistant and durable seal, outperforming other sealants like silicone sealants. As Adiseal can be applied to wet surfaces, it can also be used to carry out emergency repairs in wet conditions. Adiseal is available as a clear waterproof sealant as well as other colours and can be used for both indoor or outdoor waterproofing applications.

Waterproof sealant underwater sealing leak demonstration.
Waterproof sealant demonstration, sealing a leak instantly underwater.


Why choose Adiseal waterproof sealant?

Adiseal industrial strength waterproof sealant excels in instantly sealing leaks, even in challenging wet conditions. In the demonstration video below, Adiseal sealed a large 10mm by 250mm hole in a water-filled plastic tub, applied underwater, sealing the leak immediately even with water pouring through the hole.

Waterproof sealant demonstration video

What are the benefits of Adiseal waterproof sealant & adhesive?

  • Works in dry, wet, even underwater
  • Good initial grab (for even more grab, use Adiseal Hi-Grab)
  • Gap filler sealant
  • Resists mould
  • Over paintable (paint can be mixed into Adiseal Ultra Clear to make custom coloured sealant)
  • Non brittle (remains flexible)
  • Waterproof adhesive
  • Water resistant sealant
  • UV resistant
  • Virtually odourless (no harsh smell when applying product)
  • Isocyanate free
  • Solvent free (safe for use on sensitive materials)
  • No shrinkage or cracking (provides a better and longer lasting seal)
  • Flexible sealant adhesive
  • Prevent fungal growth
  • Prevent bacteria growth
  • Good resistance to chemicals
  • EC1 Plus certified (No VOC)
  • ISEGA certified – safe for use in food preparation areas
  • Suitable for indoor & outdoor adhesive sealant use
  • Strong sealant


Best mould resistant sealant

A good waterproof sealant also needs to be able to resist mould growth. Adiseal stood out as the sealant with the strongest mould resistance in our tests. We applied various sealants and mastics to clean plastic cups and submerged them in tap water for several days. Even after this prolonged exposure, Adiseal remained the most mould-free among the tested products.

Strong mould resistant waterproof sealant test. Adiseal vs CT1
Strongest mould resistance test results.


What is the best clear waterproof sealant?

Adiseal Ultra clear waterproof sealant lives up to its name, maintaining a genuinely clear appearance unlike some alternatives that turn out to be cloudy upon application. Unlike cheaper silicone sealants that claim clarity but often cloud up, Adiseal Ultra Clear stays crystal clear, whether dry or wet, making it the superior choice for clarity.

We conducted a test demonstrating Adiseal Ultra Clear’s ability to retain its clear appearance even after prolonged submersion in water.

Adiseal Ultra Clear has strongest colour retention in water

Clear waterproof sealant in water comparison. Adiseal Ultra Clear vs CT1 sealant clear
Colour retention of sealant. Test in water.


Colour retention test of clear waterproof sealant

We tested the clarity retention of clear waterproof sealants by applying the products inside new plastic cups. These cups were filled halfway with tap water, covered, and maintained under identical conditions for several days.

Clear sealant test in water. Adiseal Ultra Clear sealant has stayed clearest.
Waterproof sealant clear test results in water.


Adiseal top in colour retention test

After several days of being submerged in the same water, Adiseal outperformed competitors, staying clear both above and below the waterline. In contrast, competitor waterproof clear sealants turned white below the waterline, falling short.


How to use a waterproof sealant

How to use a waterproof sealant.

  1. Clean the surface

    To get a good long lasting seal, making sure the surface is clean is vital before applying the sealant. If there is any grease, dirt or mould, clean that first before applying the product.

  2. Cut the Nozzle:

    Cut the nozzle of the sealant tube making an opening that matches the desired bead size.

  3. Apply Sealant:

    Apply a steady, even bead of sealant along the intended joint or area. Maintain consistent pressure for a uniform application.

  4. Smooth the Bead:

    Use a caulking tool, spatula, or your finger (wearing a glove) to smooth and shape the bead, ensuring good coverage and a neat finish.

  5. Cure Time:

    Allow the sealant to cure as per the manufacturer’s instructions. This could take several hours to a day, depending on the product and environmental conditions.

  6. Clean Excess:

    While the sealant is still wet, wipe away any excess with a damp cloth or sponge. If the sealant has dried, carefully trim away excess using a utility knife.

  7. Test the Seal:

    Test the sealant’s effectiveness by applying water to the sealed area after it has cured. Unlike some sealants, such as Adiseal, which can be tested immediately after application, even before full curing.

Tip: To store Adiseal once opened, leave about 1cm worth of product out of the nozzle and store the tube upright in a cool dry place. Adiseal requires moisture for it to cure. The exposed part out of the nozzle will cure creating a cap. To re-use Adiseal, pull the cured part out or cut the nozzle until the uncured part is reached.

Internal and external weatherproof sealant

Adiseal is a versatile industrial strength sealant ideal for both indoor and outdoor use, excelling as a weatherproof sealing solution for various applications. Its high UV resistance, flexibility, and ability to withstand high temperatures make it perfect for outdoor sealing projects. Additionally, it cures underwater, prevents mould growth, and sustains adhesion when exposed to water, making it an exceptional choice for instant sealing in rainy conditions, particularly for roofs and gutters.

Permanent submersion

Adiseal can seal and bond underwater but isn’t designed for constant submersion. When using Adiseal to affix a tile in a pool filled with water, it’s crucial for the tile and grout to act as a barrier, preventing water from reaching the adhesive after installation. Adiseal can be suitable for such applications, even in pools permanently filled with water.


Waterproof sealant for wood

We demonstrated Adiseal’s exceptional waterproofing ability on wood by applying it to wood and brick surfaces in dry, damp, and wet conditions. This showcased its strong adhesion and weather resistance, depicted in the accompanying images.


Applying strong sealant on wood & wet brick.
Applying waterproof sealant on wood and wet brick.
Grab demonstration on wood & brick.
Instant grab demonstration of sealant on wet surfaces.


Waterproof sealant for plastic

Adiseal is a versatile waterproof sealant suitable for various materials, including plastic, particularly PVC. However, it’s not recommended for use on certain plastics like polypropylene, polyethylene or polyurethane.


Waterproof sealant for metal

Adiseal is a versatile waterproof sealant for metal as well as other materials. Prior to application, it’s essential to clean the metal surface thoroughly by removing any oil, grease, or rust to ensure a long-lasting seal on metal.



Paint on waterproof sealant

Adiseal waterproof sealant can be used with paint. It’s advisable to test oil or solvent-based paints on a small area first. Apply the sealant, let it cure, then apply the paint to check for any peeling. Although most paints work well with Adiseal, testing ensures compatibility, particularly with specific types.


Adiseal waterproof sealant is available in the following colours:

Adiseal can be manufactured in any RAL colour.

Waterproof adhesive glue

As well as Adiseal being a great waterproof sealant, it is also an excellent waterproof adhesive glue. It will provide a flexible and waterproof bond on many different construction materials.

Where to buy?

In the UK, to buy waterproof sealant from Adiseal stockists, contact us for details of your local stockist. For other countries, they can be purchased from online sellers like www.guglue.com who can ship worldwide.



Frequently asked questions about waterproof sealant

What is the best external waterproof sealant?

Adiseal is the best external waterproof sealant. With its ability to seal instantly, even underwater, it’s the ultimate choice for all your sealing needs. Its high mould resistance makes it perfect for external use, and its clear formulation stays clearest even after prolonged submersion in water. Plus, Adiseal works just as well in the rain, making it the ideal weather resistant solution for your sealing needs.

What sealant can I apply in the rain?

Adiseal weatherproof sealant is designed to work in all weather conditions, including rain, dry, and even underwater. It seals instantly, making it ideal for fixing leaks in gutters or other outdoor structures during wet weather. The sealant also provides a long-lasting, flexible seal that can withstand extreme weather conditions.

Can any waterproof sealant be used as an electrical waterproof gel?

No, standard sealant is not suitable for use as an electrical waterproof gel. Electrical insulation gel is specifically designed to withstand high voltage and remain re-enterable, in case the electrical connections need to be accessed. Using the wrong type of sealant can cause electrical malfunctions and potential hazards. It is important to use a product specifically designed for electrical insulation purposes.

How long does waterproof sealant last?

The longevity of a waterproof sealant can vary based on factors such as the quality of the sealant, environmental conditions, and proper application. Generally, a well-applied and high-quality sealant can last several years before requiring reapplication.

What waterproof sealant can be applied when wet?

Adiseal is a waterproof sealant that can be effectively applied even on damp surfaces, making it ideal for wet conditions. Its water-resistant properties ensure reliable adhesion in various applications.

What is the best sealant to stop water?

Adiseal sealant can stop water leaks even in wet conditions. Adiseal can be applied in dry, damp, wet and even underwater to seal instantly. It provides a strong, flexible and durable seal.

Can sealant stop water leaks?

Adiseal waterproof sealant will stop water leaks instantly even in wet conditions. Adiseal can be applied to dry, damp, wet and even underwater to stop water leaks. Silicone sealant can not be applied to wet surfaces so silicone sealant is not suitable at stopping water leaks immediately.

Is there a better sealant than silicone?

Adiseal waterproof sealant provides a strong weatherproof seal and is better than silicone. Unlike silicone sealant, Adiseal can be applied to dry, damp, wet and even underwater. Also unlike silicone sealant, Adiseal has the ability to seal instantly even in wet conditions.

What is the best waterproof joint sealant?

Adiseal provides a high-performance waterproof seal in joints. It can seal instantly in dry, damp, wet and even underwater. Adiseal provides a strong, flexible, UV resistant and durable seal on joints.



Suhail Matadar has extensive experience in the construction industry as an electrician, involved in installing, inspecting, and testing electrical systems in various projects. He excelled in sales, working for a major UK wholesaler, selling construction products to professionals and the DIY market. Suhail's background includes working at a leading home emergency repair company dealing with trades people. With a BEng (Hons) degree in Electronic Engineering, Suhail has worked with PLCs in the nuclear fuel manufacturing industry. During his studies, he gained practical experience at a chemical manufacturing company known for producing award-winning cleaning, hygiene, and livestock protection products for over a century. Currently, Suhail runs a global business specialising in supplying, researching, testing, and distributing chemical construction products like adhesives and sealants.