design a zero-failure waterproofing system

  • On a relative risk basis, the Structural Waterproofing system often gets relatively far less attention in design, plan review and construction than it deserves compared to other parts of the construction process.
  • Why does waterproofing for below grade structures deserve more attention you might ask? The reason is quite simple; Although waterproofing generally only represents a minor fraction of the total development costs, if it fails it can incur massive cost and liability issues.
  • Keep reading to learn the essential 5-steps to successful waterproofing





Waterproofing should last a lifetime

Our guiding principle is that a waterproofing system must be capable of protecting a structure for its entire service life, no matter what! That’s also the reason we’ve made it our mission to help the construction world achieve zero-failure waterproofing.

This means we’re here to take some of the load off your shoulders whenever you need a waterproofing specialist on your project, and we’ve also taken upon us the task of elevating the overall knowledge of advanced waterproofing solutions within the construction industry.

Knowing that not everyone is as passionate about waterproofing as we are, we’d like to share this easy-to-digest guide, intended to give you a solid understanding of how to approach design, selection and installation of a fail-safe waterproofing for below ground concrete structures.

Five CEMPROOF steps to successful structural waterproofing

There are so many components and considerations that are crucial when building a watertight below ground structure, that it would be foolish to leave anything to chance.

For that reason, we’ve defined a 5-step process that will help you secure the structural integrity of your below ground structure, for a lifetime.


zero failure design


Waterproofing design should be undertaken by a suitably qualified person and be appropriate for the specific performance required.

The performance or ‘Grade’ (level of waterproofing protection) required will guide the selection of which ‘Type’ of waterproofing is best suited to achieve a successful outcome.


waterproofing Grades:


  • Grade 3
  • Grade 2
  • Grade 1

Grade 3


Habitable accommodation – ‘No water penetration acceptable’

*Grade 3 waterproofing protection is required the waterproofing design should include a combination of two of the types of waterproofing systems.

Grade 2


Non-habitable areas – ‘No water penetration acceptable though damp areas are tolerated’

Grade 1


‘Some seepage and damp areas are tolerable, dependent on intended use’. Drainage may also be required to deal with seepage.


Our in-house technical team can offer the expertise of a Certificated Surveyor in Structural Waterproofing (CSSW).

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zero failure design

System Selection

The risk associated with the water table level will enable the waterproofing designer to determine the most appropriate waterproofing system(s) to comply with the grade of protection required.

Three ‘Types’ of

waterproofing protection


  • Type A
  • Type B
  • Type C

Type A


(Waterproofing Barriers) is usually referred to as “tanked protection” which typically relies on a waterproofing membrane to keep water out and has no integral protection against water penetration. The waterproofing membrane, depending on type, may be applied internally or to the outside of the structure. In some cases, it is sandwiched between two skins of masonry or concrete. Type A waterproofing systems include:
• bonded sheet membranes
• liquid-applied membranes
• geosynthetic (bentonite) clay liners
• mastic asphalt
• cementitious systems
• pre-applied fully bonded systems

Type B

  • In-situ concrete with or without admixtures and crack widths limited by design
  • In-situ high strength concrete with crack widths limitedby design and post construction crack injection
  • Pre-cast concrete systems assessed in accordance with Technical Requirement R3
  • Waterstops used to provide enhanced resistance to water transmission at joints in the concrete structure, e.g. at construction or day-work joints, services or other penetrations.

Type C


Drained Cavity construction: Type C systems that include a cavity drain membrane, which forms a waterproof barrier. Where the Type C system is formed using a drained masonry cavity wall, the guidance in BS 8102 (or other relevant national building standard) should be considered


Try our product configuration app to get a quick overview of what system and products your project might require.

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zero failure design


All too often errors in both detailing and workmanship, due to a lack of knowledge, experience or familiarity with various waterproofing systems, result in costly leakages and damage.

The best products in the world won’t save you if site preparation and subsequent installation isn’t carried out correctly.


In order to comply with e.g. British standard, all sitework must:

  • Meet the technical requirements
  • Take account of the design
  • Follow established good practice and workmanship

So, how do you best ensure a world class installation?

  • Select products that by design minimizes the potential for errors in application. Read more about our best-in-class installation benefits here
  • Make sure the installing contractors are properly trained on the selected products
  • Understand the importance of substrate preparation, water management, and the risks associated with poor concrete quality due to water added on site, and the potential damages to the external waterproofing caused by premature disassembling of the formwork before the concrete is sufficiently cured.
  • At all stages of the construction process, the designers, specialists, manufacturers/suppliers and installing contractors should maintain effective channels of communication.



We can provide approved applicators or alternatively can train the contractor’s or sub-contractor’s team to install all chosen waterproofing materials to a proficient standards.

The training will be supplemented by full design information, an installation method statement including detailing of joints, junctions and penetrations.


zero failure design


Avoid issues due to “as-built” changes and errors in application through regular and clear communication between architect, structural engineer, installer and/or site engineer. Regular site supervision is also critical. This will allow undesired design variations and amendments to be avoided, or planned and executed if necessary, without compromising the performance of the waterproofed structure.

We recommend that you facilitate periodic oversight and inspection, including sign off on installation in order to satisfy local requirements for building control regulations.

zero failure design


The CEMPROOF INTERNATIONAL standard system warranty covers the “Waterproofing Design” and “Product Performance” for a 20-year period. These elements are supported by full Professional Indemnity and Product Insurance in the unlikely event of a failure.

Specific ‘insurance backed project warranties are available’ through our insurance partners with an additional premium.

Last but not least, five key take outs that will make a difference

  • Confirm that the project has a waterproofing designer and that a geotechnical specialist is consulted on the geology and hydrogeology.
  • When selecting waterproofing system, it is advisable to go for more durable materials to make sure the waterproofing will last as long as the structure. Read more
  • Ensure that installers have been properly trained and recognize the importance of water management and substrate preparation before and during installation. Read more
  • Enhance coordination between the structural and architectural details, particularly at structural interfaces such as construction joints, pipe penetrations and pilings.
  • Make sure the Waterproofing design coordinator of record is always made aware of any “built in” changes or potential errors.

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Talk to an expert today – Design & application guidance

We’d love to support you along your waterproofing design and application journey. Feel safer knowing our extensive technical knowledge and experience is there to ensure you make the right choices.