Roof sealer: how to protect and waterproof your roof

Your roof is your home’s first line of defence against the British weather. Driving rain, persistent damp, freeze-thaw cycles, urban pollution, moss and lichen: the attacks are relentless, and they can compromise the weathertightness and structure of a roof within just a few years.

A water-repellent roof sealer is the established way to protect a roof for the long term. The key is choosing the right product for your roofing material, your objective and your environmental requirements. This guide covers the SCALP SAS water-repellent and oil-repellent treatments suited to each situation, what they offer, and how to apply them properly for the best result.

Why protect your roof with a water-repellent sealer?

Without a protective treatment, roofing materials (clay and concrete tiles, natural slate, fibre cement) absorb water and deteriorate gradually. The consequences can be costly: cracking caused by freeze-thaw, moss and lichen growth, water ingress and accelerated wear of the material itself. In the UK’s damp maritime climate, north-facing and shaded roof slopes are particularly prone to moss and algae.

A roof sealer creates a deep water-repellent barrier that:

  • Repels water and helps prevent water ingress
  • Limits the growth of micro-organisms (moss, algae, fungi)
  • Protects against freeze-thaw damage by reducing water absorption in the pores
  • Helps prevent urban soiling (pollution deposits, fine particulates)
  • Preserves the appearance of the material without forming an opaque film

SCALP SAS products for protecting your roof

SCALPFUGE EKO'R: a bio-based roof sealer

SCALPFUGE EKO’R is the recommended choice for homeowners and trade professionals who want to keep their environmental impact low. Made from plant-based, bio-based raw materials, it is free from volatile organic compounds (VOCs).

It waterproofs and protects roofs, façades and exterior and interior walls while maintaining the natural porosity of the substrate.

Product benefits:

  • Formulated from plant-based, bio-based raw materials
  • Limits soiling and helps prevent micro-organism growth
  • Protects against freeze-thaw cycles without altering the look of the material
  • Compatible with a wide range of substrates (tiles, concrete, stone, brick)
  • Easy to apply, for trade and DIY users alike
Plant-Based Water Repellent
Plant water repellent protection

Plant-Based Water Repellent – SCALPFUGE EKO’R

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SCALPFUGE EKO’R is a plant-based protective coating designed to safeguard walls, façades, and roofs from water ingress, rising damp, and penetrating moisture. Its water-based formula providing durable waterproofing without compromising the natural breathability of mineral surfaces. This treatment penetrates deeply into substrates, forming an invisible, microporous barrier that protects against moisture while preserving the original appearance. Ideal for sensitive materials such as hydraulic renders, natural stone, brick, marble, concrete, tiles, and slate, SCALPFUGE EKO’R also prevents surface fouling and limits microorganism growth.
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SCALPFUGE 35: a clear roof sealer

SCALPFUGE 35 is a non-film-forming, water-based water repellent. Its performance has been independently tested and certified by Buildwise (formerly CSTC, the Belgian building research institute), and it holds a European approval. Its latest-generation hydrophobic formulation, rich in active ingredients, delivers strong, long-lasting water repellency.

  • Performance certified by Buildwise (CSTC), with European approval
  • Enhanced protection against freeze-thaw damage and spalling
  • Helps prevent urban soiling
  • Clear treatment: preserves the original appearance of the substrate
  • Non-film-forming: the substrate continues to breathe
  • Ideal for roofs, façades and walls
Professional roof waterproofing
Colorless water repellent for roofs and facades

Professional roof waterproofing – SCALPFUGE 35

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SCALPFUGE 35 is a professional-grade solution designed for effective roof waterproofing and long-term protection of walls, façades, and porous mineral surfaces. This waterproof roof coating penetrates deeply into the substrate to form an invisible barrier that prevents water ingress while allowing the surface to breathe. The colourless treatment protects against moisture penetration, freeze–thaw cycles, urban pollution, and biological growth. It preserves the original appearance of materials, making it ideal for both refurbishment projects and new-build applications. SCALPFUGE 35 delivers reliable protection by reducing water absorption and limiting material deterioration caused by environmental exposure. Its deep-penetrating formula helps extend the lifespan of treated surfaces while reducing maintenance requirements. Suitable for a wide range of substrates, including :
  • Roof tiles and slate roofing
  • Brick and masonry
  • Hydraulic renders and mineral coatings
  • Natural and reconstructed stone
  • Concrete and fibre cement
  • Marble and porous mineral materials
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SCALP HYDROCOLOR PAE: a ready-to-use coloured roof sealer

SCALP HYDROCOLOR PAE combines water-repellent protection and colour in a single application. Its ready-to-use formula simplifies renovation work while giving a neat, attractive finish. Available in 4 shades, it brings a tired roof or façade back to life.

  • Two jobs in one: colour + waterproofing
  • Microporous formula: protects against the weather while letting the material breathe
  • Limits urban soiling and reduces the effects of freeze-thaw
  • Helps reduce the risk of cracking
  • Available in 4 shades for a finish to suit your property
Coloured Water-Repellent for Roof & Facade
Ready-to-use colored water repellent

Coloured Water-Repellent for Roof & Facade – SCALP HYDROCOLOR PAE

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SCALP HYDROCOLOR PAE is a ready-to-use, water-based 2-in-1 coloured water repellent designed to protect roofs and facades while enhancing their natural colour. Its advanced formula penetrates deeply to form an invisible, breathable barrier against water, freeze/thaw damage, urban pollution, and biological growth, without altering the material’s appearance.

Unlike paints or coatings that form a film, SCALP HYDROCOLOR PAE maintains substrate breathability while providing a long-lasting aesthetic finish. Ideal for roof waterproofing and facade protection, it is compatible with a wide range of mineral substrates including concrete, hydraulic and mineral renders, brick, stone, slate, and tiles.

Available in four shades—Slate, Anthracite Grey, Sienna, and Brick Red—SCALP HYDROCOLOR PAE revitalises surfaces while offering practical protection. Its compatibility with drone application makes it perfect for large, elevated, or hard-to-reach areas, ensuring uniform, fast, and safe coverage.

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SCALPFUGE COLOR: 4-in-1 protection: water repellent, mineraliser, colour and stain protection

SCALPFUGE COLOR is the most complete product in the range. In a single application it waterproofs, mineralises, colours and protects against staining. Available in 11 shades.

  • 4-in-1 action: water repellent + mineraliser + colour + stain protection
  • Enhanced protection against water, micro-organisms and stains
  • Water-based, VOC-free formulation
  • 11 shades to suit any renovation project
  • Suitable for roofs, façades, floors and exterior walls
4-in-1 Coloured Water-Repellent Treatment for Roofs, Walls & Floors
water repellent floor - after

4-in-1 Coloured Water-Repellent Treatment – SCALPFUGE COLOR

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SCALPFUGE COLOR is a premium, coloured water-repellent treatment designed to renovate, mineralise, protect, and consolidate porous surfaces. Perfect for roof waterproofing, wall protection, and exterior flooring, it penetrates deeply to form a durable, breathable layer that enhances colour and restores the natural mineral look of substrates.

This 4-in-1 solution not only waterproofs but also strengthens materials, reduces water ingress, limits freeze/thaw damage, prevents urban pollution and biological growth, and improves overall durability. Its mineralising action consolidates porous surfaces, extending the lifespan of treated materials.

Available in 11 shades (White, Pearl Grey, Anthracite, Ecru, Ochre, Sienna, Oriental Red, Brick Red, Fire Red, Slate, and a Colourless “Wet Look”), SCALPFUGE COLOR is suitable for a wide range of mineral surfaces including concrete, tiles, slate, and block paving, providing both aesthetic and functional enhancement.

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How to apply a water-repellent sealer to a roof?

Prepare the surface before application

A water repellent only bonds properly to a clean, sound and completely dry substrate. Before applying:

  • Remove moss, lichen and algae (moss removal beforehand is recommended)
  • Clean off pollution deposits and dust
  • Allow the substrate to dry fully after cleaning
  • Repair any cracks or damaged areas if necessary

If your property is listed or in a conservation area, check with your local planning authority before applying a coloured treatment, as a change to the roof’s appearance may need consent. Always read the product label and safety data sheet before use, and follow HSE guidance on working at height.

Ideal weather conditions for applying a water repellent

  • Temperature between 8 °C and 25 °C
  • Dry, still weather
  • No rain forecast for 24 to 48 hours after application
  • Substrate neither frozen nor damp

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