Masonry Water Repellent (MWR) 400: ACS

Masonry Water Repellent ACS

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The excellent water shedding properties of Masonry Water Repellent make it an ideal product for use over most masonry substrates including brick , concrete, sandstone, sand-lime bricks as well as alkaline surfaces such as new pointing and render (after about fourteen days).

The benefits are:

  • High alkaline resistance.
  • Excellent surface penetration.
  • Rapid development of water repellent effect.
  • Water vapour permeable (breathable).
  • Colourless and does not alter surface appearance.
  • Dries to a tack-free UV resistant finish.

ACS Masonry Water Repellent 400 will reduce water absorption whilst maintaining the appearance of the treated area since it does not block or impair the capillaries, thus maintaining the water vapour permeability of the substrate.

The effective reduction in moisture absorption will prolong the service life of the substrate by reducing damage caused by water such as:

  • Frost damage and Spalling.
  • Salts Efflorescence.
  • Organic (Biological) Growth.
  • Chemical Corrosion.
  • Atmospheric Pollution.

 ACS Masonry Water Repellent 400 treated masonry exhibit reduced thermal conductivity and therefore provide a straight forward way of minimizing heat loss from a building.penetrating damp


Not only will ACS MWR400 help reduce energy bills it will protect the building façade from water penetration. Nearly 80% of all damage to masonry is caused in some way by water ingress.




  1. Do not apply to hard, impervious surfaces such as granite as little improvement is made and residues may be deposited.
  2. Cracks of surface width greater than 0.15 mm and defective mortar joints should be made good with approved materials.
  3. Surfaces should be cleaned thoroughly where necessary by an approved method. Loose material should be removed by brushing or scraping. Biological growth such as mosses and lichens should be removed using ACS Boracol 5RH and the substrate allowed to dry. Salts deposits are often difficult to remove. Low levels of contamination may be removed by bristle brush or wiping with damp cloths (using clean water). Allow surfaces to dry after wet wiping. DETERGENTS SHOULD NEVER BE APPLIED AS THIS MAY NULLIFY THE WATER REPELLENT EFFECT.
  4. Sensitive structures such as windows and bitumen based materials must be fully protected to avoid contamination. Any spillages, run-offs or wind drift onto unprotected surfaces or vehicles must be prevented.


  1. Dilute 1 part ACS MWR400 with 9 parts water and mix thoroughly.
  2. Apply by coarse low pressure spray or flooding involving two or three coats. Brushes and deep pile rollers may also be used to apply ACS MWR400 but further applications may be required. Do not allow surfaces to dry between coats and apply “wet on wet”. Apply  each subsequent coat when the substrate has absorbed the previous one and is no longer shiny.
  3. Treat an appropriately sized area to achieve the “wet on wet” application. This will be influenced by the porosity of the substrate and prevailing weather conditions.
  4. Allow the material to run freely down the entire surface to about 300mm below the point of application using a continuous and regular technique.
  5. Apply to complete masonry areas rather than selected areas. Ensure the entire facade, including the mortar joints is treated. The junction between the masonry and mortar should be well treated.
  6. Application rates will vary depending on the porosity of the substrate with volumes ranging from 0.5 litres to 2 litres/m2 . Site trial applications are useful to help determine the volumes most suited to the substrate.

Post Application

  1. Post treatment protection of the masonry may be required for a short period (until surfaces are dry) in unsettled weather.
  2. Application equipment should be cleaned with water immediately after use to avoid deposition of resin in spray heads and nozzles.


0.5 to 2 litre/m2 depending on the porosity of the substrate.


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500 ml* £28.00

*500 ml of concentrate makes 5 litres of Masonry Water Repellent.