WA Sealers

Perth based supplier of innovative paving, stone & concrete cleaning and sealing products

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GuardHardener WO

  • From $6.76/m2 (RRP)
  • Price is exclusive of GST & Shipping.
  • Trade & bulk order discounts available. (Click Here)




Guard Hardener W stops rising damp and salt damage

Guard Hardener W – Stop Efflorescence, Salt Attack and Rising Damp

Guard Hardener is a surface hardener and  water repellent sealer in one. It re-mineralises porous materials and produces a strongly hydrophobic surface effect. It is highly effective for treating efflorescence and salt attack in friable materials damaged by intrusion of water, rising damp and frost.

Water, Salt and Porous Building Materials

Porous building materials like concrete, natural stone, brick and reconstituted materials can all suffer from salt damage. Liquid water can soak through the pores of these materials. It can drain down through the substrate by the forces of gravity. Or wick up through the pores by capillary action, known as rising damp.

Rising damp is a problem in it’s own right. Water can wick up through brick, stone and render to make internal walls damp. It will make non breathable paints and sealers peel off. And it provides ideal conditions for mould and mildew growth.

Further, this liquid water almost always contains some dissolved salts. All different types of minerals can make up these salts. These minerals can come from external sources, such as bore water / ground water, sea water, pool salts etc. However, salts can also be leached from the stone or concrete itself.

Mineral Leaching and Accelerated Erosion

Water Erosion, salt damage and Mineral leaching on Stone facadeThis leaching of minerals can erode the stone. But, in general only soluble species within the stone or concrete can be leached out. So the effects are minimal. However, if the pH of the water is low it is effectively an acid and normally insoluble salts will begin to dissolve into it. Examples where this can occur is around pools where too much acid is used, and in regions that experience acid rain. One of the most common causes of this accelerated leaching is when people use acids to clean stone or concrete.

Acids are commonly used to remove efflorescence, but often they make the situation worse. By dissolving minerals in the substrate they produce more salts which produces more efflorescence. DO NOT use acids to clean your stone or concrete. This is one of the quickest ways to destroy them. Use an acid replacement product like Guard Remover Eco Efflorescence and Cement.

Efflorescence and Salt Damage

When the water in the stone gets to the surface it evaporates and leaves all the dissolved salts behind. When the salts are left behind on the surface, it’s called efflorescence. Efflorescence looks horrible, but it’s mostly just cosmetic. The bigger problems occur when these salts crystallise in the pores on the surface of the stone. As the crystals grow they put stress on the stone / concrete / brick and can cause these materials to fracture. This effect is commonly called salt attack or salt damage. All these microscopic fractures makes the surface crumble. In turn these crumbly surfaces become more porous and therefore more prone to salt attack.

How to Stop Rising Damp and Salt Attack

If you can minimise salts you can reduce salt damage, but this is often difficult to achieve. But if you can stop liquid water from getting into porous substrates, or migrating through them, you can stop both rinsing damp and salt attack.

The use of waterproofing membranes are always recommended for all below grade structures. However, these are difficult, if not impossible to apply after the fact. So, if you have an active rising damp issue, that isn’t going to be the answer for you.

Most water proofing membranes are opaque, so they are not suitable for any surfaces you will see. Even if you have a clear coating it can only be applied as a positive side water proofing application. That is between the water source and the dry substrate. If water gets into the material, it needs to get out and will force such coatings off the surface in order to escape. As such they aren’t suitable for stopping any active rising damp or efflorescence issues. A breathable product is required so that the water can escape. If the water escapes as a vapour it isn’t damp and it cannot contain any salts.

How Guard Hardener W Stops Salt Attack and Rising Damp

Guard Hardener W by Guard Industry works a little different than traditional waterproofing products. It works in multiple ways to prevent the migration of water.

  1. It penetrates deep into porous materials and crystallises to harden, consolidate and water proof. Once treated, materials become far less porous and therefore less able to absorb water.
  2. It is highly hydrophobic. That is, it strongly repels liquid water. Water beads off the surface of treated materials.
  3. It is breathable. Any moisture that does get into the materials can escape as water vapour. This allows the substrate to dry out and therefore behave a naturally as possible.

Use Guard Hardener W to strengthen highly friable materials such as soft natural and reconstituted stone. Ideal protection for rammed earth and limestone block work. Guard Hardener can also be used as an anti dusting treatment.

Guard Hardener also has excellent water repellent properties that help to prevent main causes of degradation. Such as water infiltration, rising damp, acid rain, erosion, freeze / thaw cycles, development of micro organisms, salt attack and efflorescence.

Guard Hardener is a non film forming impregnation product. Substrates remain permeable to air and water vapour. It is completely invisible after application and does not change the look or feel of the treated surface. It is also UV resistant and does not discolour with age.

Use Guard Hardener W to treat masonry, stone and concrete exposed to water containing salts and minerals. Common applications include pool surrounds (headers along the pool edge), in splash zones of water features, retaining walls and other structures subject to rising damp or regular water ingress. This treatment can be used as a prevention or a cure.

For best results thoroughly clean surfaces prior to application of Guard Hardener W. Remove efflorescence and mineral stains, where present, with Guard Remover Eco Efflorescence and Cement. DO NOT use acid! It will only make the problems worse. Use Guard Cleaner Eco Soiled Floors to remove any grease oils or general build up of dirt.

Additional information

Weight 5 kg
Dimensions 18 × 13 × 29 cm

5 Litre, 250ml


Natural Look


Eco-solvent based


Hydrophobic (Water Repellent), Penetrating, Stabiliser, Surface Hardener

Product Type

Sealer, Treatment


Guard Industry


  • Protects against water and humidity, increasing the life of materials
  • Protection against stains and soiling
  • Anti-dusting action
  • Deeply consolidates
  • 10 year efficiency
  • High penetration & abrasion resistant
  • Limits efflorescence
  • Non film-forming, lets a surface breathe.
  • Excellent ageing, UV-resistance, does not yellow


  • Drying Time:  Full efficiency achieved after drying 7 days
  • Coverage: (guide only)
    • Very porous & crumbling materials:  0.5 to 2m2/litre for 2 layers
    • Porous materials:  3 to 5m2/litre for 2 layers
    • Low porous materials:  6 to 10m2/litre for 2 layers
  • Clean-up: Clean tools and equipment immediately after use with white spirit.
  • Equipment needed: low pressure sprayer with a viton joint, a brush or a roller
  • Odour:  Solvent


Guard Hardener® WO is for indoor and outdoor use wherever materials need consolidating and protecting. It can be  applied to siliceous and carbonate rocks, concrete, cement, bricks, terracotta, slate etc.


Surface preparation:

  • Apply the product to a surface that is clean, dust-free and above all dry.
  • A mechanical with a brush or chemical cleaning can be done.
  • To remove stains and marks of pollution use Guard Cleaner® Polluted facades. In case of greasy stains use Guard Cleaner® Eco Soiled floors. For efflorescence or saltpetre use GuardRemover® Eco Efflorescence & Cement. To eliminate moss and lichens, use Guard® Anti-M 24.
  • For new concrete constructions, allow substrate to stabilise (28 days) before treatment.


  • Apply product neat – do not dilute.
  • Test first.
  • Apply to the point of saturation of the substrate in 2 layers with an interval of at least 10 min.
  • Protected drying: 24 hours.
  • Full efficiency achieved after drying 7 days.
  • The treated substrate must not be covered by another coating.

Environment & Safety

  • Respiratory protection : Wear a mask (type A2P3R)
  • Hand protection : Wear rubber gloves
  • Skin protection : No special protective clothing or skin protection is required under normal conditions of use.
  • Eye protection : If there is a real risk of splashing, wear protective goggles.
  • If swallowed : Do not induce vomiting. Contact a doctor or a specialist

Data Sheets

Technical Data Sheet – GuardHardenerWO
Safety Data Sheet – GuardHardenerWO

1 review for GuardHardener WO

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  1. 4 out of 5

    John Chapman

    The test will come after rain

    (0) (0)
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