Basement Waterproofing Experts

The design of basement waterproofing is a key – but often overlooked – element in successful building design. Decisions about waterproofing made in the design stage can have wide-ranging impacts, including on spatial layout. If competent waterproofing design is not therefore included at an early enough stage, serious issues can develop as the project progresses.

The CLW advantage

Structural waterproofing demands expertise. We frequently see the results of professional architects and engineers designing waterproofing and, unfortunately, making mistakes. The reality is that structural waterproofing is a specialist field and those who work in this specialist field ought to be designing structural waterproofing. Furthermore, the expertise of a waterproofing specialist should match the complexity and scale of the project. CLW are actually experts in the field of basement waterproofing design. We hold excellent industry experience and the competence to design waterproofing.

We’ve seen the effects of ‘value engineering’ and treat water with the respect it is owed. Much of the time the big influencers in waterproofing design hold no direct appointment, don’t really hold design liability and are driven by sales of products. When this is the case, the commercial drivers push waterproofing design which can cause problems with water ingress. At CLW we position our involvement in a scheme so that we can influence design. We’ve got decent understanding of contract and liability and are able to shape the waterproofing solution so that it is robust. We also work hard to provide specifications that invite appropriate contractor input to bring about best value.

Waterproofing design coming from a material supplier revolves around a product catalogue. Technical sales staff are ultimately driven by sales. To expect this arrangement to drive anything other than a desire to sell more of the highest mark up products is naïve. CLW are independent waterproofing specialists. Our design advice is driven by a wholistic understanding of the scheme and a desire to contribute to a built environment that serves generations.

At CLW, our business is basement waterproofing design. We have the experience and knowledge to ensure a robust waterproofing solution for your project – from design through to construction. And as an independent consultancy, we are not limited to any specific products or solutions. We have no interest in upselling our materials. Our sole interest is in providing our clients with waterproofing solutions that give the necessary performance at the best value for money.

How we operate within RIBA plan of works


Outline Design

RIBA Stage 3

Spatial Coordination

Waterproofing can and does have significant implications for the design, e.g., on gross internal areas, threshold levels and more. Without competent waterproofing design at RIBA Stage 3, serious issues can develop later in the process that can be much more difficult and time-consuming to correct.

Detail Design

RIBA Stage 4a

Technical Design

Waterproofing detailed design requires coordination with other disciplines. With our knowledge and experience, we are quick to understand the relevant issues, able to clearly communicate them to relevant stakeholders, and to work collaboratively with others to solve them. Our BIM2 capabilities allow us to work in Revit and Navisworks and extract section details in order to identify issues and provide solutions. We also offer clear, easy-to-understand waterproofing performance specification documents that help ensure you buy what you need.

Procurement Advice

RIBA Stage 4b

Client Side Advice

Our experience and standing enables us to give proper consideration to value engineering and alternative waterproofing proposals. We are also well placed to scrutinise the value propositions of various warranties and insurance offerings.
RIBA 5+6

Client Side Advisor

RIBA Stage 5-6

Manufacturing & Construction

During construction further waterproofing design development is likely to occur. We are able to vet design tweaks and ensure that waterproofing remains in line with the broader strategies developed. We then continue to add value through assessment of guarantees and other handover information.


In Use Advice

RIBA Stage 7

Technical Design

RIBA Stage 7 covers the building in use. We can advise on waterproofing performance in many circumstances, including defect investigation, dispute resolution and condition surveys.

The CLW service

Our preference is to be appointed by the client, normally a developer. In this position we seek to work with the rest of the design team to understand waterproofing as a whole with a big picture perspective. We aim to understand the site, the soil conditions, the hydrogeological situation, the risk of contaminants and the flood risk. We discern the client’s wants and needs for the space, the finishes, the sustainability requirements and ventilation. With that background we shape the structural waterproofing. We don’t just select product types and draw them on section details. We influence the design of the structure so that the whole situation is suited to the behaviour of water on each site for the life of each design.

CLW should be appointed at or before RIBA Stage 3. We work with the design team to define a waterproofing design philosophy early so that all parties can be on the same page. During this phase we would be influencing issues such as pile type, ssl levels, concrete thickness, floatation considerations, crack width calculations, wall and floor build-ups, general waterproofing strategy (Type A, Type B, Type C and combined protection).

At RIBA Stage 4a CLW work with the design team to refine the waterproofing design and coordinate issues such as access panels, drainage runs concrete crack widths. We also work hard at delivering excellent
communication in both reports and drawn communications. This helps to achieve good tender documents and responses. At this stage we are also working on Performance Specifications which clearly stipulate who should undertake waterproofing, required grades of waterproofing performance, guarantee requirements and contractual lines of responsibility. We assist in tender interviews and reviews of contractor proposals.

CLW remain client side throughout the build and handover process. We are passionate about contractors who own design responsibility being empowered to make design choices and as such we work collaboratively to ensure that the end users of the final development receive the best possible 

Other design services

Beyond the normal RIBA stages of work, we also offer design review services of third-party waterproofing designs and expert witness/dispute resolution services. 

Waterproofing Design Review

When a waterproofing design has been developed by others, but this design requires a level of vetting, CLW can help by providing waterproofing design review. Our waterproofing design review service gives you confidence in your existing designs – or helps to identify weaknesses and areas for further development. We gather and collate all pertinent information to evaluate third-party waterproofing designs against existing best practice and our own expertise and experiences.

Defect Diagnosis

CLW are experienced in investigating defects in waterproofing. We are trusted by the likes of NHBC to clarify the true causes of dampness. This clarity allows all parties to resolve the underlying cause(s)  and navigate disputes and insurance claims.

CLW also work closely with Vector Leak Consultants to locate defects in buried waterproofing systems such as green roofs, service tunnels and basements. This unique capability has proven extremely valuable in very complex situations.


Dispute Resolution Services

CLW complete a lot of expert witness work in relation to waterproofing. We also assist in various alternative dispute resolution routes, including Expert Determination.

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