The Structure has no integral protection against water and relies on a membrane to be introduced internally or externally to prevent the ingress of water into the inner building fabric.
The structure itself is constructed to be integrally waterproof and the primary resistance against water ingress.
It is accepted that water could enter the building and an internal cavity is provided to depressurise and manage the water.
Waterproofing Design Specialists are tasked to recommend a “combined“ waterproofing system approach particularly where:
1. The likelihood of leakage is high
2. The consequences of leakage are unacceptable
3. Additional vapour checks are necessary for a system where unacceptable water vapour transmission could otherwise occur
With this in mind, the possible combinations of waterproofing are
Type A, B & C
Type A & B
Type A & C or
Type B & C
Usually a combination of 2 forms of waterproofing is adequate when designing a habitable space requiring a completely dry internal environment, defined as ‘Grade 3’ within BS 8102:2009. Whichever combination of waterproofing is chosen to achieve the Grade 3 environment, in most cases the safest combination will include a Type C internal cavity drain membrane system as one of the forms of waterproofing. The choice of the other system is largely dictated by the type of structure.
A typical combination waterproofing design showing Newton System 500 Cavity Drain System internally (Type C), Newton System 400 membrane externally (Type A), and Newton System 300 waterbars and waterstops within the structure itself (Type B)
Type A Protection - A high performance, pre-applied self-healing sheet membrane that features a locking fleece and a polymer hydrophilic coating. The 403 HydroBond®-GB variant also provides resistance to radon, carbon dioxide and hydrocarbon gases.
Type B Protection - Hydrophilic waterbar which swells on contact with water in order to seal either non-compressed joints such as raft to raft, or compressed joints such as at the kicker.
Type C Protection - Maintainable waterproofing solution, including a range of cavity drain membranes, pumps, pumping control panels and drainage provision. Where possible a Type C internal cavity drain system should be used as part of a combination waterproofing system, as it is the safest form of waterproofing.
Newton Systems 400, 300 and 500 are employed to provide Type A, B & C waterproofing protection
A typical combination waterproofing design showing Newton System 500 Cavity Drain System internally (Type C), Newton System 400 membrane externally (Type A) & Newton System 300 for integral waterproofing details (Type B)
Nick Wells, Advanced Basements (Christian Dior Store, Central London)
Newton highly recommend that installation is undertaken by a Newton Specialist Basement Contractor (NSBC). NSBCs can provide a substantial insured guarantee and take full design liability on the project, fulfilling the role of ‘Waterproofing Specialist’ as recommended by the BS 8102:2009 ‘Code of Practice for Protection of Below Ground Structures Against Water From The Ground’. Please contact us for a list of NSBCs in your area.
For any further information about Type C waterproofing systems, or for any technical advice about your waterproofing project please contact us please contact us on 01732 360 095 or firstname.lastname@example.org.