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British Standard 8102:2009 defines three ‘types of waterproofing and explains that consideration should be given to using two or, in some cases, even three types of waterproofing to achieve the desired ‘grade’ of waterproofing protection and to meet the client’s expectations.

Multiple types of waterproofing are especially recommended where the consequences of failure to achieve the desired grade are too high, which, it could be argued, is the case with most habitable basements.

BS 8102:2009 recommends and, more recently, NHBC Chapter 5.4 requires at least two types of waterproofing where grade 3 protection is required for structures that are more then 600mm into the ground. As such, Newton provides standard or bespoke solutions for each of the three types of waterproofing, individually or combined, depending on project requirements.

How does basement waterproofing work?: Basement Waterproofing – An Overview
The British Standard: Requirements of BS 8102:2009 
National House Building Council: NHBC Standards Chapter 5.4

Newton Waterproofing Index

The Newton Waterproofing Index (NWI) is a unique specification tool that provides a scoring system for waterproofing designs and assesses the likelihood that they will achieve the desired grade of waterproofing protection.

NWI scores vary depending on the type of waterproofing protection used and the structure they are applied to. Combining types of waterproofing will generally increase the effectiveness of the waterproofing design and, accordingly, the NWI score.

Each Newton Solution Sheet confirms the NWI score and indicates what grade of waterproofing protection can be achieved by using that specification.

Unique specification tool: Newton Waterproofing Index 
Combined waterproofing: Structural Waterproofing – An Overview 

Type A (Barrier) Protection

Type A waterproofing is defined by BS 8102:2009 as ‘barrier protection’ against water ingress. The protection is dependent on a separate barrier system being applied to the structure. This form of waterproofing is commonly referred to as ‘basement tanking’ and can be applied to the internal and external surfaces of the structure.

Type A – External Waterproofing

External Type A waterproofing systems are waterproofing barriers that are applied to the positive side of the structure. Usually continuous, the barrier is pre-applied before the concrete slab is laid, or either pre- or post-applied to the walls, depending on the method of construction.

External Type A (barrier) protection

This form of waterproofing protects the structure against ground water ingress and aggressive chemicals within the water, such as sulphates. Some waterproofing barriers will also provide protection against radon and other ground gasses as part of a combined waterproofing and ground gas system.


  • Can provide an effective barrier that fully isolates the structure from ground water, aggressive chemicals and ground gasses.

External Type A Waterproofing Newton Waterproofing Index Score: 1.1 – 3.0


Related Products & Systems

Newton HydroBond System
Newton 106 FlexProof
Newton 410 GeoDrain

Type A – Internal Waterproofing

Internal Type A waterproofing systems are waterproofing barriers, usually continuous, that are post-applied to the ‘negative’ surfaces of the already constructed structure.

Internal Type A (barrier) protection

These products are typically liquid waterproofing membranes or slurries that can be applied either by spray, trowel, brush or roller.


  • Suitable for remedial and refurbishment projects.
  • Can be the only option where external application is not feasible, such as with underpinning, or after substrate repair.
  • Partial systems and localised application are also possible.

Internal Type A Waterproofing Newton Waterproofing Index Score: 2.0 – 3.0


Related Products & Systems

Newton HydroSeal System
Newton 106 FlexProof
Newton 110 WATstop

Type B (Structurally Integral) Protection

Type B waterproofing is defined by BS 8102:2009 as protection against water ingress which is provided by the structure. A combination of correctly specified, reinforced concrete and joint sealing systems can be applied to places where there is no concrete, such as joints and services penetrations, to prevent water passing through the structure.

Type B (structurally integral) protection


  • Utilises the concrete structure as a form of waterproofing.
  • Where the reinforced concrete structure has already been designed by an engineer to be waterproof to BS EN 1992, the additional waterproofing of construction joints, service entries and penetrations will result in a fully waterproof, Type B concrete structure.

Type B Waterproofing Newton Waterproofing Index Score: 1.3 – 1.9


Related Products & Systems

Newton RASCOtank System
Newton HydroTank System
Hauff-Technik Service Entry Sealing Systems
RiveStop Tie Hole Sealing System

Type C (Drained) Protection

Type C waterproofing is defined by BS 8102:2009 as protection against water ingress into usable spaces, which is provided by the incorporation of an appropriate internal water management system.

Type C (drained) protection

Water that seeps through the structure, or any installed Type A or Type B waterproofing system, is depressurised, collected and the removed from the structure.


  • Suitable for new-build, refurbishment and remedial waterproofing.
  • Considered by many to be the safest form of waterproofing.
  • Commonly used as a second form of waterproofing due to the possibility of water entering through defects in Type A and/or Type B systems.

Type C Waterproofing Newton Waterproofing Index Score: 1.0 – 3.2


Related Products & Systems

Newton CDM System
Newton Pumping, Controls & Telemetry Systems
Newton Power Interruption Systems

Speak to our friendly, expert team

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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