Combined Waterproofing of Block Walls

AC-01 Combined Waterproofing of Block Walls

Newton Waterproofing Index Score

This solution has the capability of achieving an NWI score of 3.7, by employing 2 forms of waterproofing (Type A – Barrier Protection) to prevent ground water passing through the structural elements of the building and (Type C – Drained Protection) to ensure that the desired internal environment is achieved.

Recommendations & Standards

Where possible we would recommend a reinforced concrete structure designed to BS EN1992 (Eurocode 2) and that it is of sufficient mass and quality to resist heads of water pressure as recommended 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 a Type C cavity drain membrane system is 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.

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 Penetrations

Install Newton 315 Polymer-Waterbar to all construction joints to limit water ingress through joints in the structure. 315 Polymer-Waterbar is a high-grade, hydrophilic waterbar with high elasticity and high tensile strength.

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

Continue the waterproofing externally by applying the Newton HydroBond System to the external face of the retaining walls using Newton 108 HydroBond-LM, a spray-applied liquid membrane that cures almost immediately, or Newton 109-LM, a hand applied version used where it is logistically difficult to use a spray machine.

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

Apply 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 improve the NWI score, improve the structure with a reinforced concrete structure as per Newton Solution ABC-07.

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.