10 Best Flex Seal Spray Rubber Sealant in The UK

Last updated on 09/08/2025

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Liquid Rubber Waterproof Sealant - Leak Repair Indoor and Outdoor Coating, Water-Based, Easy to Apply, Black, 3.78 Litres

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Why We Love It

Impressive flexibility and UV stability.
Applies easily in dry conditions.
Environmentally friendly, odor-free solution.

Main Highlights

HIGHLY FLEXIBLE & DURABLE - Final membrane has over 1000% elongation preventing adhesion failure, and is UV Stable stopping the sun from degrading the product. Product remains tacky - not suitable for walking surfaces
HIGHLY FLEXIBLE & DURABLE - Final membrane has over 1000% elongation preventing adhesion failure, and is UV Stable stopping the sun from degrading the product
APPLICATION - Do not apply in wet conditions or within 24 hours of rain. Apply to a dry surface, free loose flaky paint and coatings or anything that would prevent adhesion. Typically cures within 24-48 hours!
CONVERSION - 1 US Gallon is equal to 0.83 UK Gallons - 5 US Gallons are equal to 4.16 UK Gallons
ENVIRONMENTALLY FRIENDLY - Liquid Rubber Waterproof Sealant/Coating is water based, containing no solvents, VOC's or harmful odors. Safe for humans and pets alike, can be used indoors and outdoors with no special breathing apparatus
Packaging may vary

Pro-Kleen Instant Waterproof Sealant Spray - Tough Leak Sealant Spray for Roofs, Pipes, Guttering & More - Transparent & Long-Lasting Formula - Instant Emergency Repair (4 x 400ml)

Why We Love It

Stops leaks and drips instantly.
Completely waterproof and robust.
Flexible, long-lasting transparent sealant.

Main Highlights

STOPS LEAKS AND DRIPS: Our easy to use sealant spray stops leaks and drips with ease. It’s an easy to use formula that’s perfect to use for emergencies when you need to stop leaks quickly. Whether you have a leak in your guttering, pipework, drain and much more, this Pro-Kleen leak sealer provides a trustworthy and easy solution to seal the leak quickly and efficiently
WATERPROOF FORMULA: The watertight formula dries completely waterproof. It’s super tough and robust, making it perfect for indoor and outdoor use. Whether you’re needing to fix a leaking roof or window – this is the product for you!
SAFE FOR A VARIETY OF SURFACES: This versatile formula is suitable for using on guttering, pipework, drains, windows, roofs and other leaking areas. Use our pipe sealant spray for a quick and easy fix for those pesky leaks and drips on a variety of indoor and outdoor surfaces
TRANSPARENT FORMULA: There’s no need to worry about Pro-Kleen’s sealant spray leaving behind an unappealing mark as it dries completely transparent. This means you can use it on with complete peace of mind
REMAINS FLEXIBLE AND PLIABLE FOR YEARS TO COME: Once dry, this sealant spray remains flexible and pliable for years to come! The formula is super long-lasting to prevent drips and leaks from returning after use

Seal Flex 500ml Water Based Adhesive Made From Acrylic

Main Highlights

Seal Flex 500ml adhesive made from Acrylate to<br/>Water-based

Liquid Rubber Universal Waterproof Sealant - Black - Universal Sealant Indoor & Outdoor - Concrete, Metal & Wood, Flex Roof Leak & Metal Roof - Cold & Wet Weather - PandaCoat - Made in EU (1 kg)

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Why We Love It

Ideal for various surfaces.
No priming needed for application.
Environmentally friendly and safe.

Main Highlights

STOP LEAKS FAST – Premium European-quality waterproof sealant that provides instant, reliable protection. Designed for durability, it seals cracks and leaks effectively on any surface!
A REAL ALLROUNDER - The Panda Coat universal flex sealant works indoors and outdoors. Perfect for sealing cracks in metal roofs or flat roof waterproofing applications, roof repair, balconies and gutter. Ensures a durable, weather-resistant finish for extended roof lifespan. Ready for immediate use!
EASY TO APPLY - No priming is required! Just one coat with a brush or roller suffices. Ideal for exterior liquid plastic sealant. Use two coats for long-lasting protection on roof paint and sealing slurry.
VERSATILE - Adheres to concrete, wood, metal, and more. Seals immediately, even on damp substrates. An excellent exterior waterproof sealant for universal application in any project!
ENVIRONMENTALLY FRIENDLY - Free from solvents and isocyanates, making it odorless and safe. UV-resistant, water vapor permeable, and weatherproof for reliable and eco-friendly bitumen sealant use.
FOR EVERY HOUSEHOLD - PandaCoat provides high-quality DIY solutions. UniBase MS is essential for sealing slurries, waterstop, and bitumen coating—the ideal all-rounder for lasting protection!

Pro-Kleen Instant Waterproof Sealant Spray - Tough Leak Sealant Spray for Roofs, Pipes, Guttering & More - Transparent & Long-Lasting Formula - Instant Emergency Repair (3 x 400ml)

Why We Love It

Stops leaks quickly and efficiently.
Dries waterproof, suitable anywhere.
Long-lasting and invisible protection.

Main Highlights

STOPS LEAKS AND DRIPS: Our easy to use sealant spray stops leaks and drips with ease. It’s an easy to use formula that’s perfect to use for emergencies when you need to stop leaks quickly. Whether you have a leak in your guttering, pipework, drain and much more, this Pro-Kleen leak sealer provides a trustworthy and easy solution to seal the leak quickly and efficiently
WATERPROOF FORMULA: The watertight formula dries completely waterproof. It’s super tough and robust, making it perfect for indoor and outdoor use. Whether you’re needing to fix a leaking roof or window – this is the product for you!
SAFE FOR A VARIETY OF SURFACES: This versatile formula is suitable for using on guttering, pipework, drains, windows, roofs and other leaking areas. Use our pipe sealant spray for a quick and easy fix for those pesky leaks and drips on a variety of indoor and outdoor surfaces
TRANSPARENT FORMULA: There’s no need to worry about Pro-Kleen’s sealant spray leaving behind an unappealing mark as it dries completely transparent. This means you can use it on with complete peace of mind
REMAINS FLEXIBLE AND PLIABLE FOR YEARS TO COME: Once dry, this sealant spray remains flexible and pliable for years to come! The formula is super long-lasting to prevent drips and leaks from returning after use

Polar Specialist Coatings

Polar Clear Leak Fix Spray - 2 x 400ml - Waterproof Roof SEALANT - Instantly Seals Leaks and Cracks, for Lasting Protection on Roofs, Drainpipes and Gutter Repairs, for Interior and Exterior Use

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Why We Love It

Innovative waterproofing for leaks.
Quick and easy application.
Long-lasting, reliable protection.

Main Highlights

Waterproof Seal: The ideal solution for instant waterproof sealant on leaks or cracks. Apply roof sealant paint to the affected area to seal. The paint forms a waterproof membrane to keep water out. Easy to apply with a brush or roller, ensuring complete coverage. Durable and resilient, it safeguards against damage from severe weather
One Coat Repair: Don’t waste any time sealing cracks or leaks. Polar LeakFix works in one coat, This flat roof sealant paint provides instant repair on flat or pitched roofs. With 500ml covering up to 0.5㎡, its quick-drying formula ensures minimal downtime. Ideal for both residential and commercial use, offering a reliable solution for all your waterproofing needs
Instant Protection: Formulated with reinforced fibres for tough, hard-wearing, and instant protection. This black sealant is perfect for emergency repairs or maintenance on drain pipes, gutters, and roofs. It gives long-lasting protection to cracked surfaces and performs reliably in all weather conditions, ensuring peace of mind
Easy To Apply: No primer needed before applying Polar Leakfix. Apply waterproofing sealant immediately for instant waterproof protection. Clear the affected area of moss, debris, and surface water, oil, or grease thoroughly. The sealant becomes touch dry within 3-4 hours. Designed for DIY enthusiasts and professionals, achieving thorough sealing
Multi-Purpose Use: Ideal water sealant for felt shed roofs, asphalt, bitumen surfaces, gutters, drainpipes, concrete, brick, GRP, fiberglass, and metal roofing. Available in Clear, Grey, and Black. Ensures versatility across applications, with a seamless finish for robust protection. Please note: Our paint is not compatible with copper surfaces

Gorilla Waterproof Black Coat & Seal Spray, 450ml – Flexible, Weatherproof Liquid Sealant | Seals out Water, Air & Moisture | For Roof Tiles, Brick, Wood, Metal, Concrete, Stone, Rubber, Plastics*

22% OffFree Shipping

Why We Love It

Flexible, weatherproof protective spray.
Effective against various elements.
Indoor, outdoor applicability.

Main Highlights

FLEXIBLE & WEATHERPROOF: Gorilla Waterproof Coat & Seal Spray offers durable protection with its flexible and weatherproof formula, ensuring reliable defense against the elements for various surfaces and applications.
SEALS OUT WATER, AIR & MOISTURE: Effectively seals out water, air, and moisture, providing robust defense against the elements for long-lasting durability and reliability. Once cured, the product is weatherproof and temperature resistant.
INDOOR & OUTDOOR: Suitable for both indoor and outdoor use, offering reliable protection against water, air, and moisture for various surfaces and environments. Can be used for sealing small cracks indoor and out.
GREAT FOR: Perfect for roofing, gutters, downpipes, windows/uPVC, external chimneys, and small repairs on caravans, providing effective sealing and protection. Not for flashing applications, pipes under pressure or for use inside firebox.

MIXEL Spray & Seal White Mastic Sealant, Flexible & Crack-Resistant, Quick Drying, Waterproof Formula, White Finish, Ideal for Guttering Roofs Window Pipes Soil, Spray & Seal Leak, (1PCS, 300ML)

Why We Love It

Flexible and crack-resistant seal.
Quick-drying for fast repairs.
Waterproof protection against leaks.

Main Highlights

FLEXIBLE & CRACK-RESISTANT: The Spray & Seal White Mastic Sealant is designed to be flexible and crack-resistant, meaning it adapts to surface movements without breaking. This makes it ideal for areas prone to expansion, contraction, or slight shifting, Handles temperature changes and water flow without cracking. Adjusts to wind, rain, and seasonal shifts. Expands and contracts with plumbing movements.
QUICK-DRYING FORMULA: The Spray & Seal White Mastic Sealant features a quick-drying formula, meaning it cures rapidly for fast and efficient repairs. Ideal for urgent repairs on roofs, gutters, and pipes. The seal sets in a short time, so you can resume use faster. Once applied, the fast-curing formula creates a waterproof, flexible seal that lasts.
WATERPROOF PROTECTION: The Spray & Seal White Mastic Sealant is designed to create a strong, water-resistant barrier, effectively preventing leaks and protecting surfaces from moisture damage. Prevents water penetration on gutters, roofs, windows, and pipes. Perfect for both indoor and outdoor use. Maintains its seal even under harsh weather conditions. Stops small cracks and leaks before they become costly repairs.
EASY SPRAY APPLICATION: The Spray & Seal White Mastic Sealant is designed for easy, hassle-free application with no need for complex tools—just spray and seal! No brushes, rollers, or caulking guns are required. The aerosol spray ensures a smooth, uniform seal over cracks and gaps. Ideal for both DIY users and professionals looking for fast repairs. Direct spray control minimizes drips and excess product use.
IDEAL FOR WET & DRY SURFACES: The Spray & Seal White Mastic Sealant is specially formulated to adhere even to slightly damp surfaces, making it perfect for urgent repairs in challenging conditions. No need to wait for complete drying; apply immediately to stop leaks. Ideal for areas exposed to moisture, like roofs, gutters, and pipes. Bonds effectively even with slight surface moisture, ensuring a durable seal.

Pro-Kleen Instant Waterproof Sealant Spray - Tough Leak Sealant Spray for Roofs, Pipes, Guttering & More - Transparent & Long-Lasting Formula - Instant Emergency Repair (400ml)

Free Shipping

Why We Love It

Stops leaks and drips efficiently.
Formula dries completely waterproof.
Remains flexible for years.

Main Highlights

STOPS LEAKS AND DRIPS: Our easy to use sealant spray stops leaks and drips with ease. It’s an easy to use formula that’s perfect to use for emergencies when you need to stop leaks quickly. Whether you have a leak in your guttering, pipework, drain and much more, this Pro-Kleen leak sealer provides a trustworthy and easy solution to seal the leak quickly and efficiently
WATERPROOF FORMULA: The watertight formula dries completely waterproof. It’s super tough and robust, making it perfect for indoor and outdoor use. Whether you’re needing to fix a leaking roof or window – this is the product for you!
SAFE FOR A VARIETY OF SURFACES: This versatile formula is suitable for using on guttering, pipework, drains, windows, roofs and other leaking areas. Use our pipe sealant spray for a quick and easy fix for those pesky leaks and drips on a variety of indoor and outdoor surfaces
TRANSPARENT FORMULA: There’s no need to worry about Pro-Kleen’s sealant spray leaving behind an unappealing mark as it dries completely transparent. This means you can use it on with complete peace of mind
REMAINS FLEXIBLE AND PLIABLE FOR YEARS TO COME: Once dry, this sealant spray remains flexible and pliable for years to come! The formula is super long-lasting to prevent drips and leaks from returning after use
EASY TO USE FORMULA: For best results, we recommend applying to clean, dry surfaces that are free from dust, dirt and rust. 1. Spray in thin coats until you have the desired thickness. 2. We recommend plugging larger holes and voids with Aluminium foil before spraying to obtain a better seal. 3. Masking tape can be used to prevent the product from going onto other areas. If in doubt, spray the product in an inconspicuous area first. Use the product in well-ventilated areas only. After use, invert the can and spray to clear the nozzle to prevent blockages

Duel Autocare Flex Polymer Spray Sealant/Hydrophobic Coat Paint Sealant/Repels Water/Dirt/Provides Premium Panel Protection Against Water/Amazing shine - No Hassle/Easy To Apply

6% Off

Why We Love It

Easy to use.
Leaves an amazing shine.
Durable for 6-8 weeks.

Main Highlights

EASY TO USE & MAINTAIN – our Flex Polymer Sealant is simple to apply – making for a effortless cleaning experience
AMAZING SHINE – your vehicle will be left with a deep gloss finish with smooth and reflective surfaces - giving a luxurious and professional look
HYDROPHOBIC - Dirty will no longer cling to your vehicle with both beading and sheeting water behaviour
HYDROPHOBIC – dirt will no longer cling to your vehicle with both beading and sheeting water behaviour – making Flex the perfect solution for protecting and enhancing the appearance of your vehicle
DURABILITY – 6-8 weeks – Flex is a polymer sealant constructed from reactive polymers – with its high quality materials, this product is built to withstand the test of time
VALUE FOR MONEY – 20 applications per bottle – not only is Flex designed to deliver exceptional performance and durability – but it is also designed to deliver exceptional value for money
MADE IN THE UK - We pride ourselves on delivering high-quality class leading detailing products of unsurpassed quality. Our goal is to manufacture and provide the very best detailing products that we can. Before launching any products, we ensure they have been thoroughly tested by some of the leading detailers in the country. The Duel brand is a stamp of quality

8.9

Excellent

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We scanned 288 products

We reviewed these offers relevant to the Flex Seal Spray Rubber Sealant within online retailers such as Amazon, eBay and other local retailers, ensuring we covered all major brands and models. The products we selected come from trusted brands like Liquid Rubber, Pro-Kleen, Polymarine, Pandacoat, Polar Specialist Coatings, Gorilla, MIXEL, Duel Autocare, all of which have a reputation for consistently delivering high-quality products that users love and innovative approaches for function & design.

For the best Flex Seal Spray Rubber Sealant in the market, we considered we took a deep dive into 1441 online reviews , focusing on elements like user satisfaction, performance in real-world conditions, and long-term reliability. Our ranking also evaluates each review’s relevancy, authenticity, up-to-dateness and depth so that the comparison is more sound.

We concluded that:

The clear winner of our analysis is Liquid Rubber Waterproof Sealant - Leak Repair Indoor and Outdoor Coating, Water-Based, Easy to Apply, Black, 3.78 Litres. We love many things about this product by Liquid Rubber. What sets it apart from the competition is Impressive flexibility and UV stability. , Applies easily in dry conditions. , Environmentally friendly, odor-free solution.
The best value product for most shoppers and where user satisfaction is continuously the highest is Pro-Kleen Instant Waterproof Sealant Spray - Tough Leak Sealant Spray for Roofs, Pipes, Guttering & More - Transparent & Long-Lasting Formula - Instant Emergency Repair (4 x 400ml) by Pro-Kleen based on online reviews by bloggers, experts and online shoppers.
The biggest bargain at the moment for Flex Seal Spray Rubber Sealant and the best cost-to-value ratio is Gorilla Waterproof Black Coat & Seal Spray, 450ml – Flexible, Weatherproof Liquid Sealant | Seals out Water, Air & Moisture | For Roof Tiles, Brick, Wood, Metal, Concrete, Stone, Rubber, Plastics*at Gorilla with a 22% discount.
Our list of the best Flex Seal Spray Rubber Sealant is updated regularly to reflect new releases and changes in product availability, so be sure to check back often for the latest rankings and discounts.

10 Best Flex Seal Spray Rubber Sealant in The UK

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We scanned 288 products

We concluded that: