Everbuild 402 Water Seal 5L

Everbuild 402 Water Seal 5L

By Everbuild · Model: WAT5 · Building Materials

Silicone-based water repellent for exterior brick, stone, and concrete. Provides invisible, long-lasting protection from water damage.

  • Invisible finish — does not change the appearance of treated surfaces
  • Silicone-based formula for long-lasting water repellency
  • Suitable for brick, stone, concrete, render, and mortar
  • Allows substrate to breathe — does not trap moisture
  • Coverage up to 5m2 per litre depending on porosity
  • Prevents water ingress, frost damage, and efflorescence
Check Price on Amazon

Overview

Everbuild 402 Water Seal is a penetrating silicone-based treatment that makes exterior masonry surfaces water-repellent without altering their appearance. Applied by brush, roller, or sprayer, it soaks into the substrate and lines the pores with a silicone layer that causes water to bead and run off the surface rather than soaking in. Unlike surface coatings, it remains breathable, allowing moisture vapour from within the wall to escape — a critical property that prevents the damp problems associated with non-breathable sealers.

In-Depth Look

Water ingress through porous masonry is one of the most common causes of damp in UK homes, particularly on exposed elevations that bear the brunt of prevailing weather. Everbuild 402 Water Seal offers a straightforward solution that stops rain soaking into brickwork without changing its appearance or trapping moisture inside the wall.

How It Works

The product is a clear, water-thin liquid that penetrates into the pores of masonry rather than forming a surface film. Once absorbed, the silicone component lines the pore structure, creating a hydrophobic barrier that causes water to bead on the surface. Because the treatment sits within the pores rather than on top of them, it remains invisible and does not create a glossy or wet-look finish. Critically, the treated surface remains vapour-permeable — moisture from inside the building can still pass through the wall and evaporate, preventing the condensation and damp issues that occur with non-breathable coatings.

Application and Coverage

The liquid is applied liberally to dry masonry using a brush, roller, or low-pressure garden sprayer. A flood coat is recommended, applying enough product that it remains wet on the surface for several minutes before being absorbed. Coverage varies considerably with substrate porosity — soft, porous brick may absorb 5 litres over just 10-15 square metres, while dense engineering brick will go much further. Two coats applied wet-on-wet give the best results on very porous surfaces.

Verdict

Everbuild 402 Water Seal is an effective and affordable solution for protecting exposed masonry from water penetration. Its invisible, breathable finish makes it suitable for any building where preserving the natural appearance of brickwork or stonework is important, and it provides genuine protection against the penetrating damp that plagues many UK properties.

Specifications
Volume5 litres
TypeSilicone-based water repellent
Coverage3-5m2 per litre (depending on porosity)
ApplicationBrush, roller, or low-pressure sprayer
Drying Time1-2 hours (full cure 24 hours)
FinishInvisible
Suitable SurfacesBrick, stone, concrete, render, mortar

Who It's For

  • Homeowners dealing with penetrating damp on exposed or porous external walls
  • Property maintenance professionals treating chimneys, parapets, and exposed masonry
  • Anyone wanting to prevent frost damage and efflorescence on brickwork

Pros & Cons

Pros

  • Genuinely invisible finish preserves the natural look of masonry
  • Breathable formulation prevents trapped moisture and associated damp issues
  • Effective at stopping penetrating damp on porous brickwork
  • Easy to apply with brush, roller, or garden sprayer

Cons

  • Requires dry weather and a dry substrate for effective application
  • Coverage varies significantly depending on how porous the surface is
  • Needs reapplication every 5-10 years depending on exposure
Check Price on Amazon
Affiliate Disclosure: This page may contain affiliate links. If you purchase a product through one of these links, we may receive a small commission at no additional cost to you. This helps support our research and keeps this site running. Full disclosure.

Related Products