Masonry Water Repellent Application London
Breathable water repellent treatments that prevent rain penetration while allowing trapped moisture to escape from within the wall.
What Is Masonry Water Repellent?
Masonry water repellent is a clear, breathable treatment applied to brickwork that prevents liquid water from being absorbed into the wall while still allowing water vapour to pass outward. This means rain is repelled from the surface, but any trapped moisture within the wall can still dry out naturally.
Unlike paint or film-forming coatings, breathable water repellents penetrate into the masonry pores and line them with a hydrophobic layer. The wall looks the same after treatment but water beads on the surface instead of being absorbed.
This treatment is particularly valuable for exposed elevations where pointing is generally sound but the brick itself is porous enough to absorb driven rain. It provides a protective layer that significantly reduces water uptake without changing the appearance of the building.
Water repellent is not a substitute for repointing failed joints. It works best when applied after pointing repairs are completed, providing additional protection to the repaired elevation. It is part of a preventive maintenance strategy that is consistently cheaper than reactive repair.
Signs That Water Repellent May Help
Persistent Damp After Repointing
If damp continues after pointing has been repaired, the brick itself may be absorbing driven rain through its face.
Heavily Exposed Elevations
South-west facing or high-level walls that receive sustained wind-driven rain benefit from additional protection.
Porous or Soft Brick
Older London stock bricks and other porous masonry types absorb water more readily through the brick face.
Preventive Measure
Applied proactively after repairs to reduce the risk of future water ingress, particularly on single-skin or solid wall construction.
How We Apply Masonry Water Repellent
Preparation
The wall must be clean, dry and have sound pointing. Any failed joints are repaired first. The surface is brushed down to remove loose material and organic growth.
Application
The repellent is applied by low-pressure spray in two saturating coats, ensuring full coverage and penetration into the masonry pores. We use rope access where suitable to reach upper elevations.
Curing
The treatment cures within 24 hours in dry conditions. Once cured, the hydrophobic layer is active and water will bead on the surface rather than being absorbed.
Longevity
Quality silane/siloxane treatments typically last 10-20 years depending on exposure. No ongoing maintenance is required during this period.
Benefits of Masonry Water Repellent
Prevents Water Ingress
Stops rain being absorbed through the brick face, reducing damp risk on exposed elevations significantly.
Fully Breathable
Unlike paint, allows trapped moisture to escape as vapour. The wall can dry naturally from within, preventing trapped dampness.
Invisible Finish
Does not change the appearance of the brickwork. Suitable for conservation areas and listed buildings where appearance must be maintained.
Frequently Asked Questions
Protect Your Masonry From Water Penetration
A single application provides years of breathable protection. Preventive treatment is consistently cheaper than dealing with the consequences of water ingress.