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AC-28 Combination Waterproofing of Underpinning


Newton Waterproofing Index Score

This solution has the capability of achieving an NWI score of 3.5, by employing 2 forms of waterproofing (Type A – Barrier Protection) to limit ground water ingressing behind the (Type C – Drained Protection) to ensure that the desired internal environment is achieved.

Newton Waterproofing Index 2.6 - 3.5

Recommendations & Standards

Where possible we would recommend a reinforced concrete structure designed to BS EN 1992 (Eurocode 2) and that it is of sufficient mass and quality to resist heads of water pressure as recommend by BS 8102:2009, the only place that water will enter is at the joints, basically where the concrete isn’t.

The structure should be designed to be as watertight as possible, even where Type C cavity drain membrane system are to be used, as although they are able to deal with high levels of water ingress, it is good practice to ensure that they are only dealing with seepage that manages to pass through the structure. It is the recommendation of BS 8102:2009 that Type C systems are maintainable. Because all Newton Type C waterproofing specifications include perimeter drainage channels, the whole system is maintainable.

For more information about NWI scores and how they can help with your project design, read our page explaining the Newton Waterproofing Index and how it works.

Type A – Provide a Complete and Continuous Waterproof Barrier to the External Surface

Pre-apply Newton 403 HydroBond ready for the reinforced concrete slab. 403 HydroBond is a high-performance composite sheet membrane featuring a locking fleece and a polymer-hydrophilic coating.

Type B – Prevent Water Ingress Through the Construction Joints and Service PenetrationsNewton-Solution-AC-28-NWI-score

Mechanically fix Newton 302 Injection Hose with Hose Clamps ready for concrete placement. 302 Injection Hose is used for sealing construction joints in earth-retaining concrete structures.

Type A –  Continue the Complete Waterproof Barrier to the External Surface

Apply Type A Newton 107F to the internal concrete surfaces of the walls and slab. 107F is a cementitious coating for the waterproofing and protection of concrete and masonry that can be spray applied and is ideal for large projects.

Type C – Isolate the Internal Habitable Space and Fixtures and Fittings from Dampness and Water Ingress

Install the Newton CDM System internally, including a safe means of drainage to remove any ingressing water. The Newton CDM System comprises of cavity drain membranes, drainage, pumps and control systems and is ideal for projects where a completely dry internal environment is required.

Further Information

To obtain the full Solution Sheet for this specification, including Technical Drawings and NBS Clauses, or to find a solution suitable for your project, please fill out the form below or email our Technical Team at tech@newtonwaterproofing.co.uk.

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Our staff are able to provide guidance for projects of all sizes, whether you require some general advice about damp or waterproofing, or support with technical drawings and specifications.

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