Cementitious Tanking

Cellar Tanking Systems

These wall tanking products are applied directly onto the masonry substrate of the building to create a barrier that water cannot penetrate. Internal finishes are then applied over the tanking slurry to produce a dry habitable area internally.

Cement Tanking Preparation

Preparation is always the key to a successful cement tanking system. Unlike cavity drain systems, all previous coatings, renders, plasters, paints etc. MUST be removed back to the original masonry substrate. Any defective joints or voids must be raked out to a sound substrate then repaired flush with the rest of the masonry. In cellar tanking situations, a cove joint should be formed in the floor slab. See technical brochure for more details.

When applying waterproof concrete and wall tanking products, it is essential that there is a key for the product to bond to. In some situations, for example on waterproof concrete, this may be hard to achieve. In these cases, we suggest the use of a bonding slurry coat (the approximate mix is 1 part SBR bonding additive : 1 part water: 5 parts cement) which is then brush applied over the substrate. This then offers a key for the cementitious tanking to adhere to.

Applying Wall Tanking

Applying wall tanking products is relatively easy. Simply apply the priming spray (PermaSEAL Salt Inhibitor) to the surface then apply a minimum of two coats of PermaSEAL Tanking. Depending on the product you will need to wait either an hour or 24 hours between coats.

Finishing a cellar that has been tanked can be achieved by applying a minimum of a 10mm coat of sand and cement or Permagard Renovating Plaster to the wall tanking then either finishing with dot and dab plaster boards or direct skim finish to the rendered surface. Read our complete guide to tanking a cellar. 

Please note: It is extremely important that the wall tanking is rendered. If left exposed and dot and dab finish is used, you may experience condensation between the surfaces which will give the appearance that the tanking has failed. It is also worth noting that when drying, the wall tanking must be well ventilated otherwise what is known as “sweating” can occur where water droplets appear on the surface and can make it appear that the wall tanking product has failed.

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For further information and advice regarding waterproof cement and cellar tanking systems please contact one of our specialist advisors. They will be able to help with any questions you may have around tanking slurries.