Mud Brick Water Repellent

Product Name:



Mud brick water repellent is a solvent-based silane/siloxane impregnant for mud brick or other earth buildings. The product is designed to penetrate into the capillaries of substrate surfaces and render the substrate water repellent. This water repellent zone reduces the absorption of water or efflorescence or other water-borne staining materials which are responsible for the bulk of the deterioration in earth building materials. The treatment will not significantly change the appearance of the substrates and the vapour permeability. However, a slight darkening of the surface may occur for some substrates.

Recommended Uses:

Mud brick water repellent is recommended as a water repellent sealer for mud brick or other earth buildings. It is also suitable for other substrates including stabilised earth/rammed earth, natural stones, concrete masonry, bricks, and tiles & grout. Some of the important features of Mud brick water repellent include:

  • Penetrates into substrate surface.
  • Permanently bonds to the substrate with no peel or blister.
  • UV, alkali stable and durable formulation.
  • Reduces water penetration, efflorescence and water-borne staining.
  • Does not significantly change the surface appearance and vapour permeability.
  • Easy application and cost effective.

As masonry materials vary significantly, a test MUST be carried out prior to application to find out the suitability of this product for the purpose.

Use Instructions:


Please read the product information for the correct application and safe handling. Do not apply if rain or extreme weather conditions are expected. The surface to be treated should be dry, firm and free from grime, oil and any previous coatings/sealers. If necessary, the surface should be washed with a suitable detergent in water and allowed to dry. All cracks should be filled with proper grouting materials and allowed to cure before application. A test prior to application is strongly recommended to determine of the number of coats required and suitable consumption rate.

MUD BRICK WATER REPELLENT can be applied using brush, roller or spray. However, the product is preferably applied by saturation flooding using a hand pressure spray or airless spray equipment to avoid direct contact of the brush or the roller with the earth building surfaces. Sufficient material should be applied onto the surface to ensure adequate penetration. For the vertical surface, the product should be applied as a liquid thin film stream which runs down the surface approximately 30-40cm. A second application should follow immediately after the first coat is absorbed by the surface. This is termed a “wet-in-wet” application. The object is to saturate the surface to allow a better penetration.

For horizontal surfaces, the product should be applied by flooding the surface for about 10 minutes to ensure the penetration of product into the surface.  If the sealer is quickly absorbed by the substrate after the first application, a second coat may be required immediately. Any remaining liquid on the surface which has not been absorbed by the surface after 10 minutes should be removed to avoid any excessive accumulation of the sealer in surface areas which may cause an uneven finish.

The number of applications depends on the permeability of the substrate. Generally, for very dense surfaces one application may be enough but for permeable substrates, two or more coats “wet-in-wet” may be required.

Do not splash or spray the product onto any area you do not wish to treat.  If splashing occurs the product should be removed with a cloth damped in a solvent such as mineral turpentine immediately.

Consumption rate

The consumption of MUD BRICK WATER REPELLENT varies significantly depending on the permeability of the substrate.  It may be of the order of 1-10 m² per litre per coat or could be out of this range significantly.

After application

The initial surface water repellency will develop after the surface is dry.  Full curing may take 24 hours or up to 7 days.  Avoid heavy traffic or any staining for at least 24 hours.  The equipment can be washed in a solvent such as mineral turpentine.

Pilot testing and quality control

Due to the variation of building materials, it is strongly recommended that a pilot test on a small area on site should be conducted prior to application to find out the suitability of this product for the purpose.

Typical Data:

  • Appearance: Colourless liquid with hydrocarbon solvent odour
  • Solids content:<50% by weight
  • Specific Gravity:0.79g/ml at 20 ºC
  • pH value:Not allocated
  • Solubility in water: Insoluble in water
  • VOC content: >50%
  • Flash point:>61°C

Important Note:

Mud brick water repellent penetrates into the capillaries and renders the surface water repellent while still leaving most of the capillaries open to allow water vapour to pass through. It reduces water absorption by capillary action. However, it has a limited resistance to water penetration particularly under prolonged contact or hydrostatic pressure. Therefore, in some cases where the substrate is very permeable or there is extreme wind driven rain, resistance to water penetration or water-borne staining may not be adequate.

Handling & Storage:

Mud brick water repellent is a hazardous and combustible material. Refer to the material safety data sheet for safe handling. Follow good industrial hygiene procedures when using this product. Vapour inhalation and skin or eye contact should be avoided by wearing proper protection. Wear an air-purifying respirator if there is a risk of exposure to high vapour concentrations. Wash hands after handling. The product should be stored in closed containers in a cool dry place away from any fire and ignition sources. The product has a shelf life of 12 months in a sealed original container under 25ºC.

Use with sufficient ventilation away from any fire or ignition sources!

Keep out of reach of children!


Mud brick water repellent is available in 5, 20 and 200 litre metal drums.

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