Thompson’s Water Seal 5L protects bricks stone and concrete

Manufactured by Thompson's

Thompson’s Water Seal 5L is a professional-grade, ready-to-use waterproofing solution to protect exterior bricks, stone, concrete, and wood from water damage and weather-related deterioration. Its advanced micro silicone emulsion penetrates deep into porous surfaces, creating an invisible, breathable barrier that repels rainwater while allowing trapped moisture to escape. This prevents cracking and surface breakdown caused by freeze–thaw cycles, ensuring long-lasting protection.

Unlike traditional sealers, Thompson’s Water Seal can be applied directly to damp surfaces, saving time during unpredictable weather conditions. The hydrophobic wax formulation also reduces moss, algae, and plant growth, helping to maintain a clean, dry finish over time. Low odour and easy brush or spray application provide reliable coverage for large outdoor areas without harsh fumes.

Key Features & Benefits

Robust waterproofing: Deep-penetrating formula blocks water ingress and prevents freeze–thaw damage.
Breathable protection: Allows moisture vapour to escape, reducing the risk of trapped damp.
Easy application: A brush or spray can be applied to damp surfaces for quick results.
Anti-moss technology: Reduces the growth of moss, algae, and lichen to protect surface integrity.
Low odour: Comfortable to use outdoors without strong solvent fumes.
Long-lasting coverage: Protects against weathering, staining, and cracking for years.
Cost-effective: One coat typically covers up to 10 m² per litre, depending on substrate porosity.
Trusted performance: Suitable for domestic and commercial exterior maintenance projects.

Sizes & Coverage

Pack size: 5 L
Coverage: Up to 10 m² per litre, depending on porosity
Drying time: Touch dry in around 2 hours; second coat can be applied after the first has dried

Why Choose Thompson’s Water Seal

Thompson’s Water Seal offers fast, efficient waterproofing that penetrating deep into masonry and wood, ensuring superior resistance to rain and frost. Its easy-to-use formula and long-lasting protection make it ideal for homeowners and contractors seeking reliable exterior sealing for walls, driveways, patios, and garden features.

Thompson’s Water Seal 5L is a multi-purpose exterior waterproofer designed to protect outdoor surfaces from moisture damage, freeze–thaw cracking, and long-term weathering. Its advanced micro-silicone emulsion penetrates deep into porous materials, forming an invisible barrier that repels rainwater while allowing surfaces to breathe. This makes it suitable for domestic and commercial projects where reliable, long-lasting protection is essential.

Brickwork & Masonry Walls—These are Ideal for sealing exterior brick walls, blockwork, and stone façades to prevent penetrating damp, efflorescence, and frost-related damage. The hydrophobic coating blocks pores, stopping rainwater from soaking in while keeping the wall's natural appearance intact.
Concrete Surfaces—Thompson’s Water Seal reduces water absorption to minimise cracking, surface spalling, and moss or algae growth, ensuring a cleaner, more durable finish. It is perfect for patios, driveways, garden paths, garage floors, and concrete steps.
Exterior Wood & Timber Structures: Protects wooden fences, pergolas, sheds, decking edges, and timber cladding from moisture ingress, swelling, and decay. The breathable seal helps wood stay dry without trapping moisture that can lead to rot.
Stonework & Garden Features—This product is Suitable for natural stone walls, decorative planters, ornaments, and retaining walls where Freezing-thawing action or heavy rainfall can cause erosion and staining.
Rendered & Cement Surfaces: Provides effective water repellence on cement-based renders, roughcast, and pebbledash finishes while maintaining vapour permeability to prevent internal condensation.
Problem Damp Areas—It can be applied to slightly damp surfaces, making it an excellent solution for urgent repairs or rapid protection during wet seasons when dry application is complex.

Whether used on homes, boundary walls, or landscaping projects, Thompson’s Water Seal offers a clear, non-film-forming finish that preserves the substrate's natural look while delivering durable, year-round weatherproofing.

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Frequently Asked Questions

What surfaces can I use Thompson’s Water Seal on?

It can be applied to exterior brickwork, stone, concrete, render, and unpainted timber to create a water-repellent barrier while maintaining a natural appearance.

Can I apply it to damp surfaces?

Thompson’s Water Seal can be applied to slightly damp surfaces, making it ideal for urgent protection even in unpredictable weather conditions.

How many coats are recommended for complete protection?

One generous coat is often sufficient, but highly porous or exposed surfaces may benefit from a second coat for maximum durability and long-lasting water repellence.

How long does it take to dry?

Under normal conditions, the first coat dries in around two hours. If applying a second coat, allow at least two hours before recoating to ensure proper absorption.

Does it change the colour or look of the surface?

No, Thompson’s Water Seal dries to a clear, invisible finish that does not alter the natural texture or colour of brick, stone, or timber.

Is it suitable for interior use?

No, this product is designed for exterior use only and should not be used inside homes or enclosed areas.

Can I paint or decorate over Thompson’s Water Seal?

Painting is not recommended as the water-repellent layer can prevent paints or coatings from adhering correctly to the surface.

How often should I reapply the product?

For best results, reapply every 3–5 years or when water no longer beads on the surface, indicating that the waterproof barrier has weakened.

Will it prevent moss or algae growth?

The micro-silicone emulsion helps reduce moisture retention, discouraging moss and algae build-up on treated surfaces.

Can it be used on previously painted walls?

No, the product is designed for bare, porous substrates. Painted or sealed surfaces should be stripped or cleaned thoroughly before application.

Is Thompson’s Water Seal safe for plants and grass?

Avoid direct contact with plants and lawns. Cover or rinse surrounding vegetation before and after application to prevent potential damage.

What is the coverage rate per litre?

Coverage varies with porosity, but typically one litre treats up to 10 m² on smooth surfaces or around 6–8 m² on rough, highly absorbent substrates.

Can it protect against freeze–thaw damage?

Yes, blocking moisture penetration helps prevent cracks caused by water freezing and expanding within bricks, concrete, or stone during cold weather.

How should I clean tools after application?

Simply wash brushes and equipment with clean water immediately after use to remove any remaining product before it dries.

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£29.99 (inc VAT)

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Size

5LTR

Product variants

*subject to stock levels at the time of your order.

Thompson’s Water Seal 5L protects bricks stone and concrete

Key Features & Benefits

Sizes & Coverage

Why Choose Thompson’s Water Seal

Frequently Asked Questions

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