Published on 20 December 2018 15:48

Structural Waterproofing Design Strategies to BS 8102: 2009

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Key Learning outcomes
  • The importance of BS 8102:2009 and how to design waterproofing systems.
  • The “Types” of UK waterproofing systems used to protect structures.
  • An explanation of how to achieve different levels of waterproofing protection in the UK.
  • Why waterproofing failures happen, how to avoid them, and why to use professional waterproofing contractors.
  • Other uses for waterproofing products, and sustainability in UK waterproofing.
The aim of this article is to provide you with a technical insight into the modern world of structural waterproofing in the UK, as dictated by the code of practice for the waterproofing industry, British Standard 8102:2009.

Topics will include how different levels of protection can be achieved by combining waterproofing systems, as well as why some waterproofing systems fail, and what can be done to deal with failures whilst remaining compliant with the British Standard.

As the leading independent UK supplier of waterproofing and damp proofing systems, Newton Waterproofing is well qualified to provide guidance. We have been protecting buildings since 1848, and have been instrumental in the invention and introduction of industry-changing concepts such as the first damp proofing and cavity drain systems.

In 2017 we also launched the Newton Membrane Recycling Service, the first and only scheme of its kind in UK waterproofing. Available exclusively via Newton Specialist Contractors, the service already recycles over 5 tonnes of HDPE waterproofing membrane per year, and can trace how much recycling is contributed by each project for inclusion in your own sustainability data.

We are also still – as we were back in 1848 – a family owned and run business.


High external ground levels are a conduit for water, and it doesn’t matter if the ground is 10 centimetres or 10 metres higher than the internal floor, water can still enter. Whilst removing external ground alleviates this risk, in cases where this is not possible we must consider waterproofing measures.

When designing waterproofing, there are three defining factors for providing effective protection:

1. The recommendations of BS 8102:2009 and the insurer.
2. The form and type of the proposed structure.
3. The requirements for the internal space.

Reference Materials

British Standard 8102:2009 is the “Code of practice for the protection of below ground structures against water from the ground” and provides industry recommendations and guidance on dealing with and preventing the entry of water into a structure below ground level.

Although BS 8102:2009 is not law, it is the document which expert witnesses will use to pull apart bad waterproofing designs in cases of litigation or dispute.

Other important reference documents include the technical manuals issued by construction insurers such as the NHBC, the LABC and Premier Guarantees.

Design Philosophy

When planning a below-ground structure, waterproofing strategies must be considered from the earliest stages of the design process.

The British Standard therefore recommends that a “Waterproofing Specialist”, such as a Certificated Surveyor in Structural Waterproofing (CSSW) and/or a Waterproofing Design Specialist (WDS), should be included in the design team to create a waterproofing solution with the best chance of success.

It is also important to note that in cases of litigation or dispute, if a waterproofing specialist has not been involved in the design, then the designer can be culpable.

Requirements of the Structure

Although the intended use of the structure can influence the waterproofing, we always recommend designing to resist a full head of hydrostatic pressure (water to the full depth of the below-ground structure).

Whilst a risk assessment should always be performed on the local water table, and whilst this may indicate that the risk is low, designers need to protect structures from water not only in the ground, but also water introduced into the ground, such as burst water pipes, or new adjacent structures diverting existing water courses.

It is a brave person who bets that water will never come to bear against a structure, and accordingly the British Standard recommends designing to expect a high water table at some point in the life of the structure.
British Standard 8102:2009 is the most important technical document in the UK waterproofing industry, governing best practice and setting out design recommendations and installation requirements.
British Standard 8102:2009 is the most important technical document in the UK waterproofing industry, governing best practice and setting out design recommendations and installation requirements.
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17-20 Sovereign Way
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Tel +44 (0)1732 360095
James Hughes
Tel +44 (0)1732 360095
The information contained in the CPD article web pages is not intended and accordingly shall not be relied upon either as a substitute for professional advice or judgement or to provide legal or other advice with respect to any particular circumstance. RIBA Enterprises accepts no responsibility for loss occasioned to any person acting or refraining from action as a result of the information contained.
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