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Basements- Waterprooofing options - BS 8102

Note that BS 8102:2009 was revised in March 2022 and gives further guidance on developing robust and maintainable waterproofing solutions, including greater consideration of the buildability and potential issues that can occur during follow-on works.

BS 8102 defines 3 Types of water-resistant construction;

A Barrier (Membrane) protection

The structure has limited integral protection and relies permanently on a waterproofing membrane. The membrane must be able to cope with groundwater pressure plus any imposed or service loading or movements. The membrane can be applied internally, externally or sandwiched between inner and outer walls.


B Structurally integral protection

The structure itself provides a water resistant shell. Typically reinforced concrete, the design must meet strict parameters. Note that cracking is unlikely to be avoided so some degree of water penetration is not uncommon.


C Drained protection

The structure provides primary resistance to water penetration but incorporates a drained cavity within the structure which is permanently relied-on to collect and remove water.

These options can be combined e.g. Type A and B, A and C or B and C, depending on the risk of water penetration and environment required.

See Basement Information Centre

Example of external barrier
Example of structural integral
Example of drained cavity



Acknowledgement: Concrete Society