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Vandex BB75 / BB White / BB75 Z

Vandex BB75 is a cementitious waterproofing slurry (tanking slurry) with hydrophobic properties, resistant to water and moisture.

Vandex BB75 is applied by trowel or spray to surfaces such as concrete, masonry, and render, which have to be sealed and protected against the influence of water and moisture. Typical areas of application include:

• Basement / cellar waterproofing and refurbishment
• Underground car parks
• Retaining walls
• Lift pits
• Tanks / reservoirs / water treatment works
• Sewer / sewage treatment plant waterproofing (BB75 Z)
• Fish ponds & water features

Once cured, Vandex BB75 tanking slurry forms a waterproof coating (tested up to 7 bar). It can be employed against active and passive water pressures, and is approved for use in contact with potable water. The initial and final bonding capability of Vandex BB75 is excellent, making it suitable for application to horizontal as well as vertical surfaces. It is durable, resistant to frost and heat after setting, whilst remaining vapour-permeable. The properties of Vandex BB75 can be further enhanced by using the “Vandex PK75” or “Vandex Cemelast Liquid” polymers as a gauging solution – the resulting products being referred to as Vandex BB75 E and Vandex Cemelast.

Vandex BB75 is not intended to provide a decorative finish. In most cases, the Vandex BB75 waterproofing layer is covered with a suitable plaster such as Vandex Refurbishment Plaster.

Vandex BB White

Vandex BB White is a version of Vandex BB75 based on white Portland cement. Its characteristic white colour makes it particularly suitable for use on exposed surfaces, e.g. potable water reservoirs.

Vandex BB75 Z

Vandex BB75 Z is formulated to have enhanced sulphate resistance, making it suitable for use in sewage treatment plants and sewer / manhole refurbishment projects.

Vandex BB75 / BB White / BB75 Z Application

Preparation

1. 

   Surfaces to receive Vandex BB75 treatment must have a clean and well-keyed surface to ensure maximum bonding. Structural defects must be fixed before treatment begins [1].
2. 

   Remove all surface laitance, shutter release agent, curing compound, loose particles, etc. by means of light, wet or dry sandblasting, high pressure water jetting or wire brushing.
3. 

   Carefully rinse (pre-water) all surfaces to recieve Vandex BB75. Pre-water several times so that the substrate is thoroughly saturated. When Vandex BB75 is applied, the surface should be damp but not wet. Any surface water on horizontal surfaces must be removed.
4. 

   Place 25 kg of Vandex BB75 into a clean container, then add 4.5 – 6 litres of water. Stir for at least 3 minutes with a mechanical mixer.

[1] For more details of structural defects that must be repaired prior to Vandex BB75 application, refer to the Vandex BB75 application guidelines, which can be downloaded in PDF format from the ‘downloads’ tab at the top of this page.

Application

Do not apply Vandex BB75 at temperatures below 5°C (40°F) or to a frozen substrate.

1. 

   To apply Vandex BB75 by brush, it should be applied from the bottom upwards, and any excess should be worked sideways. All cavities and air holes must be filled, thereby excluding trapped air. If two layers are applied, it is recommended that the second layer is applied whilst the first layer is still damp on the surface [2].
2. 

   To apply Vandex BB75 by trowel, an initial scape coat is applied for maximum adhesion to the substrate, working from the bottom up. All cavities and air holes must be filled, thereby excluding trapped air. The first layer is then applied to the thickness specified in Table 1 above. If two layers are applied, it is recommended that the second layer is applied whilst the first layer is still damp on the surface [2].
3. 

   To spray Vandex BB75, a suitable fine mortar spraying device must be used. The amount of material required and the air used must be adjustable so that the optimum spray pattern can be achieved. The nozzle diameter should be approximately 6 mm, depending on the spray gun used. The compressor performance must be at least 5 bar pressure, delivering 500 l/min.
4. 

   To apply Vandex BB75 with a spray applicator, the first layer is applied using a circular motion with the sprayer [3]. If two layers are applied, it is recommended that the second layer is applied whilst the first layer is still damp on the surface [2]. The final layer can be left direct as a spray finish or smoothed finely with the trowel.
5. 

   If using a spray applicator, the spray finish provides an “orange peel” texture which is easy to clean.

[2] The waiting time before applying the second layer is approximately 2 – 4 hours, depending on local climatic conditions such as humidity, temperature, etc. The first layer must not be damaged during application of the second layer.

[3] The nozzle must be held at a 90° angle to the substrate being treated and the distance between the nozzle and the surface will vary depending on the spray gun / compressed air used.

For maximum effectiveness, it is essential that the applied layers of Vandex BB75 are kept damp for at least 5 days and protected against evaporation by sun and wind. Careful post-watering should be carried out at intervals, starting from the day following the application. Alternatively, the surfaces can be covered with plastic sheeting, wet mats or moist sand. The use of curing compounds is not recommended.

The freshly treated surfaces should be protected from rain for a minimum period of 24 hours. Surfaces treated with Vandex BB75 should be protected from frost for at least 5 days. If necessary, cover them with insulation mats.

Detailed application instructions can be found in the Vandex BB75 application guidelines, which can be downloaded from the ‘downloads’ tab at the top of this page.