Type A Waterproofing

British Standard 8102:2022 is the ‘Code of Practice for Protection of Below Ground Structures Against Water Ingress’ and defines Type A waterproofing as “barrier protection” which is applied to either the internal or external surface of a structure in order to resist the pressure of water trying to enter the building. Type A membranes are the products that are referred to when people talk about the process of “tanking” a basement in order to protect it from water ingress. Barrier waterproofing membranes that can be applied to the external ‘positive’ side of the structure include both pre-applied, self-healing sheet membranes, and post-applied liquid membranes that can be linked to the above-ground DPC in order to completely encapsulate, or “tank”, the basement in a continuous waterproof layer.

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Waterproofing barrier membranes that can be applied to the internal ‘negative’ side of the structure include a variety of liquid-applied membranes or slurries that can be installed either by spray machine, trowel, brush, or by roller directly onto the internal wall surface. These membranes must actively hold back any ingressing water, so it is crucial to select the correct product and to ensure that the substrate is prepared correctly.

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Type C Waterproofing

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British Standard 8102:2022 defines Type C waterproofing as “drained protection” where water leaking through the structure is accepted into voids and air spaces, created by cavity drain membranes that are strategically placed to the inside of the structure, depressurising the incoming water and safely removing it from the property. The Newton CDM System is certified to the BES 6001 standard for responsible sourcing, and includes a range of BBA certified cavity drain membranes. These membranes, coupled with the bespoke sump and pump configurations, backup systems, telemetry and ancillary options, makes it the most reliable and maintainable waterproofing solution for any habitable space below ground.

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Combination Waterproofing

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For more robust waterproofing protection, BS 8102:2022 recommends combining two or more Types of waterproofing. The Newton CDM System can therefore be combined with our Type A solutions Newton HydroBond or Newton HydroSeal. 

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Our Technical Team will work with you to design the right combination of structural waterproofing methods to ensure the end user’s desired internal environment is achieved, in accordance with current legislation and best practice. Professional waterproofing designers should always consider using more than one type of waterproofing to provide enhanced protection to the structure and achieve the necessary environmental grade.