Stormseal - Wet Apply Waterseal

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Stormseal - Wet Apply Waterseal

Click to zoom

Stormseal - Wet Apply Waterseal

Click to zoom

Stormseal - Wet Apply Waterseal

Click to zoom

Stormseal - Wet Apply Waterseal

Click to zoom

Stormseal - Wet Apply Waterseal

Click to zoom

Stormseal - Wet Apply Waterseal
Stormseal - Wet Apply Waterseal
Stormseal - Wet Apply Waterseal
Stormseal - Wet Apply Waterseal
Stormseal - Wet Apply Waterseal
Stormseal - Wet Apply Waterseal

Stormseal - Wet Apply Waterseal  

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39.40Inc. VAT32.83Ex. VAT Next Day Delivery Available

Stormseal the breathable brick & masonry water-seal you CAN apply in damp conditions. Unlike conventional surface damp treatments, Stormseal doesn’t rely on dry weather for successful application. Effectively seal damp external walls, even in winter.Read More

Product Code:26st5
Coverage:4-6 m2 / litre
Application:2 Coats
Colour Palette:

The colours shown here are dependent upon screen settings or monitor calibration, they are a guide only. The actual colour may vary.

Sizes & Tester:Size:
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Stormseal Masonry Water Seal


Unstoppable – Whatever the weather

When we talk about damp in a property, our thoughts almost automatically turn to “rising damp” whereas in reality “penetrating damp” is by far the more common problem.  In winter some walls simply never dry out, as even on dry days they may remain shaded and cold, especially on north-facing elevations.  This can be frustrating, as the “Achilles’ heel” of most liquid water seals, is that you have to wait for the wall to dry out before applying them.  Paradoxically when you need them most, you just can’t use them!

Stormseal is different, it positively thrives on application to damp surfaces.  In point of fact, it doesn’t work properly unless the wall is damp!  This single innovation makes Stormseal the most versatile water-seal available and facilitates all year-round control of lateral penetrating damp.

This latest version of Stormseal has many outstanding features, including:

  • Seals damp walls from further moisture penetration
  • 100% Breathable & micro-porous
  • Apply in damp weather conditions
  • Seals masonry and cement mortar joints in one easy application
  • Suppresses salting on brick walls (efflorescence treatment)
  • High resistance to alkalis
  • Rapid development of water repellence
  • Dries completely clear, without staining
  • Improves energy efficiency by reducing evaporative heat loss
  • Controls moss and mould growth on damp walls
  • To seal moisture-laden limestone


How does it work?

Lateral penetrating damp describes what occurs when an external wall becomes saturated and subsequently transmits that moisture to the inside of a building, usually exhibiting as damp patches on the plaster and other decorative finishes.  The problem arises for two basic reasons:

a) Building materials deteriorate over time or were weak to begin with

b) Water is a relentlessly persistent invader

The deterioration is often gradual over many years.  Mortar joints crack with repeated freeze/thaw expansion and contraction, which provides a path for rainwater to enter the structure.  Or perhaps the stonemasonry has some “soft” stones which absorb moisture, especially during periods of prolonged stormy weather.  It could even be that a poorly installed window cill or stone lintel is causing a small reservoir of water to accumulate or “pond”.  Brick walls also deteriorate over time and may become porous, especially if they are solid as opposed to cavity construction.

There are innumerable variations on the above theme, but the resulting moisture penetration results in all the same outcomes: damp plaster, black mould, degraded air quality and timber decay.

Of course, one product alone will not solve all penetrating damp issues, but Stormseal provides builders, homeowners & damp proofing professionals with a significant defence against the problem and crucially, without having to wait for dry weather.  It limits the absorption of water, which is the starting point for most decay.

It achieves this by embedding an invisible hydrophobic shield, developed from solvent-free polysiloxanes, which are susceptible to hydrolysis.  Hydrolysis occurs only after application to the substrate.  This then reduces the capillary absorption of the wall which it has penetrated but does not block pores or capillary channels.  There is therefore little or no impairment to the wall’s ability to breathe.

Stormseal can be used in many penetrating damp situations including:

  • Domestic properties
  • Commercial properties & warehousing
  • Industrial letting units
  • Rental properties
  • Terraced houses
  • Detached and Semi-detached properties

Indirectly it may also reduce condensation.  A weakened solid brick or stone wall may absorb moisture to an extent that is hidden deep in the masonry, without actually pushing all through to the plaster.  This can be described as partial porosity and it nevertheless exerts a significant cooling effect on the wall, especially in winter because when the moisture evaporates off, it carries heat away with it.

Stormseal restricts the ability of absorbent building materials (old bricks, soft mortar joints etc.) to soak up that moisture in the first place, with two effects:

a) Evaporative heat loss (described above) is greatly reduced

b) Condensation “cold spots” are eliminated from internal walls

Other vulnerable areas of masonry include parapet walls and chimneys, both of which benefit from maintenance applications of Stormseal.Chimneys have a very specific range of problems, especially in older properties (e.g. Georgian and Victorian) because decades of burning coal will have left deposits of sulphates, nitrates and carbon within the chimney.When these come into contact with moisture and the chlorides naturally present in bricks, sand and stonework, the resulting cocktail can be impressively corrosive.Apply Stormseal to prevent rainwater from providing that destructive catalyst, even in tough winter conditions that would frustrate conventional water repellents.


How to use Stormseal?


Brick walls, stonemasonry and rendered finishes should be thoroughly cleansed of all dirt, carbon deposits, green mould, moss and other organic growth.  Where the mortar joints are in good condition and there are no “blown” brick faces, careful pressure washing with a fan nozzle (do not use “rotary jet” or “turbo” nozzles) will provide rapid removal of most contaminants.  Where the substrate is considered fragile, use Kingfisher Eco Brick Cleaner to remove carbon and salt staining.  Agitate with a scrubbing brush and repeat cleanse/rinse cycle two to three times if necessary.  Moss accumulations may be removed by scraper and/or wire brushing.


Surface Sanitise

Often when organic matter is cleansed from an external wall it is prone to grow back again with a vengeance.  This seems counter-intuitive until you understand that cleaning may remove the moss growth for example, but it also spreads the invisible spores around too, which quickly re-establish, often to a wider area.  An application of Kingfisher Bio-Wash kills these spores and micro-root systems, so is considered an essential surface preparation before applying Stormseal.


Re-point mortar joints

Cracked, softened or even dislodged mortar joints are a common source of moisture ingress and no breathable water repellent alone, will remediate such issues.  Loose cement or lime mortar should be mechanically raked out to a depth of at least 20mm and new mortar pointed in to create a water-proof joint.  We recommend Kingfisher Pointing Mortar & Pointing Solution for best results.



a) Stormseal is a ready-to-use formula and should be applied directly to the porous brick, stone or render.  Do not apply to engineering brick, dense stone (granite), polished stone or marble.

b) If the substrate is dry, spray mist with clean water using a manual pump sprayer.  The objective is for the surface to appear damp but not glistening wet so that the moisture draws in the active formula without dilution.

c) 2 coats “wet on wet” should be applied or perhaps more accurately; “wet on damp”.  As for the water misting, you are aiming for the first coat to have soaked in just enough that the surface is not glistening, before applying the second coat.  Apply to refusal by brush or low-pressure sprayer.

d) We suggest starting at the top of the work area and working downwards, allowing runs and drips to be captured and spread by brush (even if the main method of application is spray).  Work in the horizontal plane and avoid spraying overhead.


How much will I need?

The coverage rate is 4 to 5 sq m per litre, so a 25-litre drum of Stormseal should treat at least 50 sq m with the recommended two coats.



a) Do not apply to engineering brick, dense stone (granite), polished stone or marble

b) Do not apply during precipitation

c) Cover up if rain expected within 4 hours of application

d) Not for use indoors unless well ventilated during application and curing


Technical Support

As always, we recommend that you read the Technical Data Sheet & Safety Data Sheet thoroughly before commencing any work.  If in doubt please call us for advice, we are here to help.

Wet seal water seal

Good so far water pearls off like it says only time will tell


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