10 Best External Window Sealant in The UK

Last updated on 02/08/2025

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Best Choice

9.8

Exceptional

Everbuild

12X Everbuild White External & Internal Acrylic Frame Sealant - 310ml

Why We Love It

Generous 310ml size. Convenient 12-tube box. Sleek white color.

Main Highlights

Size 310ml.
12 tubes per box.
Colour white.

BONDIFY Waterproof Window Frame Sealant White 500g x 3PCs, 100% SOLVENT-FREE Paintable Silicone Sealant Acrylic, White Mastic for Filling Cracks and Gaps, Bathroom, Kitchen and Door, UPVC use

6% OffFree Shipping

Why We Love It

Flexible and paintable finish.
Non-toxic and no odor.
Ideal for interior use.

Main Highlights

BONDIFY SILICONISED SEALANT (WHITE - 3PCs) : BONDIFY paintable sealant is a general purpose, water based sealant for caulking, sealing and decoration uses in waterproofing, gap filling, wood frame joints, doors & windows sash, drywall, plaster, marble, tile & brick works, painters sealant for interior works.
KEY FEATURES : Its siliconized structure, makes it possible to handle movement up to 15%. Water based, Mildew resistant, Non-toxic No Odour. Very low VOC content. Over Paintable. Environmental friendly, easily clean up with water.
APPLICATION AREAS -1 : Sealing of low movement joints between various construction materials(wood, concrete, brick etc.) It’s ideal for sealing and filling gaps, cracks, and joints around windows, frames, doors, baseboards, drywall, plaster, woodwork, moldings, and trim.
APPLICATION AREAS-2 : Used in areas that are not in direct contact with water, like along the edges of countertop, backsplash, toilet seat, bathroom floor wall joint.
STANDS OUT : BONDIFY Siliconized Sealant provides a flexible, paintable finish and is often applied to areas that require a durable, weather-resistant, and moisture-resistant seal.

UniBond Outdoor Extreme Repair Sealant, Polymer Based Outdoor Sealant Suitable for Use on Various Materials*, Weather Resistant and Waterproof Sealant, Translucent, 1 x 389g Cartridge

27% OffFree Shipping

Why We Love It

Highly durable and resilient.
Ideal for all weather.
Superior wet surface adhesion.

Main Highlights

Bonding & Sealing - This premium polymer-based sealant is suitable for bonding and sealing joints indoors and outdoors. Ideal for windows, doors, and facades
Durable - This waterproof and weather-resistant joint sealant cures in approximately 24 hours. Suitable for indoor and outdoor use achieving long-lasting results
Wet surface adhesion - When fully cured, this polymeric sealant is highly resilient and it provides stronger adhesion to a wide range of damp and wet surfaces than silicone sealants
Polymer technology - Thanks to unique technology, the joint filler is impact and shock-resistant for the toughest repair jobs, and will not shrink over time

Gorilla 1144110 All Conditions Sealant Silicone Clear 295ml

38% OffFree Shipping

Why We Love It

Fast set in 30 minutes.
Repels mold and mildew.
Works on multiple surfaces.

Main Highlights

FAST SET - Can be exposed to water after just 30 minutes
REPELS MOULD & MILDEW - Long lasting performance
MULTI SURFACE - For use on Porcelain, Metal, Vinyl, Laminate, Stone, Ceramic, Stainless Steel, Granite, Wood, Glass
DURABLE FORMULA - Won't yellow, shrink or crack over time
PREPARATION: All surfaces should be clean, dry and free of old sealant. For gaps larger than 12 mm, use a backer rod to fill the gap. Best results achieved if applied above 5°C.

Hemway - Construction All-In-One Hybrid Polymer Sealant & Adhesive - Crystal Clear | Transparent, Anti-Mould, Waterproof & Paintable | 300 ml

Free Shipping

Why We Love It

Resistant to Mould and Water.
Advanced, High-Grab Polymer Formulation.
Eco-friendly and Fast Curing.

Main Highlights

HYBRID POLYMER TECHNOLOGY: All-in-one technology combines the flexibility of silicone, with the paintability of acrylic caulk & the high-strength seal of adhesives; ideal for construction, renovation, finishing & fixing. Hemway is a British brand and we manufacture our products to the highest standards of quality.
VERSATILE USE: Delivers a crystal clear, transparent finish on wood, glass, plastic, metal, PVC & concrete, plus compatible with water-based paints; an ideal floor, tile, bath, window, wall, door, shower, toilet, roof & gutter leak sealant.
ANTI-MOULD & WATERPROOF: Our unique non-shrink formula is anti-mould, waterproof, weatherproof, chemical & UV resistant, offering a durable, long-lasting finish that is resistant against fading & stains.
ECO-FRIENDLY: This vegan & cruelty-free adhesive & sealer is more environmentally safe than other silicone alternatives; a solvent-free, odourless, non-toxic & low VOC product.
QUICK CURE & HIGH COVERAGE: Covers a 6 mm bead x 9.25 mm length & fast curing within 24 hours at 23°C, with 50% R/H; provides resistance from -50°C to 120°C, making it suitable for many conditions, including high-humidity areas.

UniBond 2078170 Outdoor Window and Door Frame Sealant, White Outdoor Sealant, Durable Weatherproof Door and Window Sealant, Cartridge

26% OffFree Shipping

Why We Love It

Permanently flexible and durable.
Multi-material application usability.
25-year guarantee assurance.

Main Highlights

Permanently flexible – Our Unibond waterproof sealant Provides a durable flexible perimeter seal for exterior window and door frames, protecting you from the elements
Multi materials – This durable adhesive sealant can be used on various materials such as wood, uPVC, polycarbonate, and metal - suitable for most window and door frames
Flexible and waterproof – As well as providing strong and flexible sealing, this window frame sealant is also waterproof, so it can stand up to harsh weather conditions
Long lasting – as long as you follow the instructions for use, this exterior sealant will stand the test of time, giving you peace of mind when doing outdoor sealing jobs
Package contents – UniBond Outdoor Window and Door Frame Sealant, weather-resistant silicone sealant, flexible and long-lasting waterproof sealant, white, Cartridge

Everbuild Everflex 450 Premium+ Builders Silicone Sealant – Waterproof Seal – Suits Most Building Materials – Internal and External Use – White – 300ml

Why We Love It

Versatile for many substrates.
High UV stability.
Available in various colors.

Main Highlights

MULTI-PURPOSE – This strong, neutral cure low modulus sealant is ideal for use on expansion joints. It's perfect for internal and external perimeter pointing around PVCu, wood and other window frames.
VERSATILE – Adheres and seals to most substrates including glass, metals, plastic, and wood. It's compatible with polycarbonate, acrylic and lead and has low dirt pick-up for work with PVCu.
HIGH RESISTANCE – High resistance to plasticiser migration. Suitable for use over water-based and solvent-based paints.
FLEXIBLE – Ideal as an expansion joint sealant with a +/- 25% flexibility factor, certified for façade, glazing, cold climate and sanitary applications.
WATERPROOF – Forms a permanent waterproof seal for parapets and roofs and joint sealing to pre-formed panels with excellent UV stability. It provides general glazing, sealing and draughtproofing.
RANGE OF COLOURS – Also available in buff, black, grey, oak, translucent, and brown.

Everbuild White External Frame Sealant - 4 Tubes

EVO-STIK Window & Door Frame Sealant, Waterproof, Flexible, Overpaintable, Lasts up to 15 Years, Colour: White, Size: 290ml

11% OffFree Shipping

Why We Love It

Weatherproof and reliable protection.
Excellent adhesion to surfaces.
Mould-resistant and overpaintable.

Main Highlights

EVO-STIK Window & Door Frame Sealant, Filled acrylic emulsion paste ideal for sealing around door and window frames
Weatherproof: prevents damage caused by penetration of water and keeps out draughts
Excellent adhesion to most materials including wood, uPVC and metal, For interior and exterior use
Lasts up to 15 years, Contains fungicide to combat unsightly mould growth, Overpaintable when dry
Contents: 1x EVO-STIK Window & Door Frame Sealant, Waterproof, Mould-Resistant, Flexible, Overpaintable, Colour: White, Size: 290ml

Sika Stixall – Extreme Power Sealant And Adhesive – Waterproof – Black – 290ml

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Why We Love It

High grab strength, zero sagging.
Weather and water-resistant.
Bonds underwater or in rain.

Main Highlights

HIGH-PERFORMANCE – Crafted using hybrid polymer technology, it has incredible initial grab strength, zero sagging and fills gaps with ease.
IDEAL FOR INTERIOR AND EXTERIOR USE DEPENDING ON THE APPLICATION – Resistant to weather, water, temperature and chemicals, you can use this as an adhesive inside and out plus as an interior sealant. (NOTE: Crystal Clear colour is not suitable for exterior use)
VERSATILE – Has incredible high-grab adhesion to a wide range of materials, including glass, metals, plastic, concrete, wood, and so much more – it bonds even underwater or in the rain.
PROFESSIONAL FINISH – This quick-curing mix develops a skin in only 10 minutes and is paintable once completely dry with water-based paints for a high-quality finish to your DIY projects.
EASY TO APPLY – Insert the cartridge into your caulking gun, snip the tip and apply as needed to your chosen materials.
LONG-LASTING – This completely waterproof adhesive and sealant is resistant to temperature extremes between -40°C and +100°C, as well as a range of chemicals once fully cured, meaning it can be considered for durable applications.
MULTIPLE COLOURS – Available in Black, Brown, Anthracite, White, Crystal Clear and Grey

8.9

Excellent

We scanned 1837 products

We reviewed these offers relevant to the External Window 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 Everbuild, BONDIFY, Unibond, Gorilla, Hemway, EVO-STIK, Sika, all of which have a reputation for consistently delivering high-quality products that users love and innovative approaches for function & design.

For the best External Window Sealant in the market, we considered we took a deep dive into 9186 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 12X Everbuild White External & Internal Acrylic Frame Sealant - 310ml. We love many things about this product by Everbuild. What sets it apart from the competition is Generous 310ml size. Convenient 12-tube box. Sleek white color.
The best value product for most shoppers and where user satisfaction is continuously the highest is BONDIFY Waterproof Window Frame Sealant White 500g x 3PCs, 100% SOLVENT-FREE Paintable Silicone Sealant Acrylic, White Mastic for Filling Cracks and Gaps, Bathroom, Kitchen and Door, UPVC use by BONDIFY based on online reviews by bloggers, experts and online shoppers.
The biggest bargain at the moment for External Window Sealant and the best cost-to-value ratio is Gorilla 1144110 All Conditions Sealant Silicone Clear 295mlat Gorilla with a 38% discount.
Our list of the best External Window 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 External Window Sealant in The UK

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We scanned 1837 products

We concluded that: