Bostik Xtreme: Stronger, Safer and Built for the Trade

Approx read time: 3 minutes

The sealants and adhesives market is flooded with options; sometimes it can be hard to know which to select from the shelf and more importantly, if you can trust that it’s going to do the job.

Firstly there are multiple different technologies to choose from: silicones, polyurethanes, butyls, two component products, epoxies; and each of these technologies has its advantages over the others. Then there are multiple brands, price points and levels of quality… It can be mind boggling to stand in the aisle and assess the choices available, not to mention time consuming.

But it doesn’t have to be that way…

Bostik Xtreme Sealants & Adhesives!

Utilising an emerging adhesive technology known as Modified Silyl Polymers or MSP (sometimes referred to as Hybrid Polymers), the Bostik Xtreme range combines all the best advantages demonstrated by silicone and polyurethane technologies, yet boasts even greater bond strength.

More than that, Bostik Xtreme will adhere to a very diverse range of substrates including wood, metal, plaster, plastics, masonry and glass – and will even bond these surfaces in the wet or underwater.

As if this wasn’t enough cause for bragging rights, Bostik Xtreme does all this whilst remaining less harmful than other products on the market. All products in the Xtreme range contain no solvents nor isocyanates and are low VOC, meaning no more strong fumes whilst you work.

The range includes four products: High Tack, Flex, ClearFix and Fire Seal; and each product contains the benefits above whilst also providing unique features to cover all jobs, big or small.

Xtreme High Tack is a high performance and high early strength adhesive. Demonstrating impressive initial grab, High Tack will stick just about anything to everything and will not slump in vertical applications. The immediate hold means that in most cases no further mechanical fixing is required of the bond during curing, through the use of screws, nails, clamps or braces. Apply the adhesive, stick A to B, and walk away. Don’t worry, the first time our chemists showed us, we didn’t believe it either.

Xtreme Flex can be considered the all-rounder in the team. It can be used as a general purpose sealant or adhesive with impressive bond strength and flexibility, expanding to a maximum of 400% before breakage. Flex is also water potable, WaterMark approved and UV resistant, making it perfect for applications in contact with drinking water or exposed to the elements. Leaky roof or gutter? Not anymore.

Xtreme ClearFix is a high performance sealant and adhesive that is, as the name suggests, extremely clear – crystal clear in fact. ClearFix is ideal for glass on glass sealing or bonding applications where in kitchens, bathrooms and laundries. Just like Xtreme Flex, it is water potable, WaterMark approved and UV resistant, although not recommended for continued UV exposure as the clarity of the product may be affected over time.

Lastly, Xtreme Fire Seal is a high performance, fire rated sealant for use in control joints and electrical/plumbing penetrations. Tested in accordance with AS1530.4, Xtreme Fire Seal meets a 4 hour fire retardancy rating across a wide variety of configurations, up to a maximum joint width of 30mm. Used internally or externally, Fire Seal is non-bubbling, so particularly effective for fire rated builds in humid climates where many polyurethane solutions frequently experience issues with bubbling. For the full list of rated configurations, view the installation guide, available on the Xtreme Fire Seal product page at

For more information on Bostik Xtreme products or where to find the range, check out the range available on the NHS online store