What Is a Waterproofing Design Specialist (WDS) - and Who on Your Project Is One?

Direct answer

A Waterproofing Design Specialist (WDS) is the named, competent person who owns the waterproofing design on a below-ground structure - the grade each space requires, the system type, the structural interfaces and the performance specification that holds it together. It is a design discipline, not a trade and not a product. The recognised minimum competence is the Certificated Surveyor in Structural Waterproofing (CSSW); for complex work the Property Care Association’s Waterproofing Design Specialist register is the stronger benchmark. The role exists because BS 8102:2022 expects someone competent and accountable to own this, and on most commercial basements no such person is named until something goes wrong.

Full explanation

The phrase “waterproofing design specialist” describes a role that most projects assume is being filled and that, on inspection, frequently is not. The value of naming it is that it creates a category in everyone’s head: a single accountable owner of below-ground water, distinct from the architect, the structural engineer, the main contractor and the waterproofing supplier. When that category is empty, the risk does not disappear - it falls into the gap between disciplines.

What the role actually does

A WDS is responsible for the strategy before they are responsible for any detail. That means establishing the BS 8102 grade for each below-ground space against its intended use, conducting the water risk assessment, selecting the waterproofing type or combination of types that suits the ground and the structure, and writing the performance specification that lets the work be procured and verified. It is upstream, strategic work, and it is most valuable early - which is why the decisive moment is usually RIBA Stage 2, before the cost plan and the structure harden.

Competence: CSSW as the floor, the WDS register as the benchmark

Competence is not a matter of opinion here, and BS 8102:2022 is explicit that the work requires it. The Certificated Surveyor in Structural Waterproofing (CSSW) is the recognised baseline qualification and the floor below which you should not go. But CSSW began life as a survey credential, and survey knowledge is not the same as design competence. For complex, deep or high-consequence basements, the Property Care Association’s Waterproofing Design Specialist register is the stronger benchmark, because it is built around the act of designing rather than diagnosing. The honest position is that the qualification is necessary but not sufficient: competence has to be paired with genuine independence from any product being specified, or the design quietly bends toward what someone wants to sell.

Getting on the register is earned, not bought

The Property Care Association’s Waterproofing Design Specialist register is not a directory you pay to join. It is awarded only after application and peer review, which is precisely why the listing means something. An applicant must already be a PCA member and hold the CSSW certificate - and must then prove the one thing CSSW alone does not test: that they can actually design.

The evidence requirement is concrete. The applicant submits two worked examples - full waterproofing designs on two different basements - reviewed independently by two members of a PCA panel. Weak submissions are rejected at this stage. Those that pass go forward to an in-depth competence interview spanning the whole design role: skills, knowledge, experience, planning, contract-risk analysis, design specification, materials, methodology, sequencing, design oversight, handover sign-off and maintenance. That breadth is the point - a waterproofing designer’s job runs from early planning to handover and maintenance, and the register tests competence across all of it.

Which is why, for a highly complex basement, the PCA Waterproofing Design Specialist register is the best place to find a designer who can genuinely carry the role - not simply someone who holds the qualification.

Who holds this at CLW

Three of CLW’s consultants are on the PCA Waterproofing Design Specialist register: Ben Hickman (Technical Director), Johnny Etkind (Senior Waterproofing Design Consultant) and Adam Leatherdale (Design Manager). Given how the register is awarded, that is a deliberate concentration of the exact competence this role demands - and each name can be checked directly on the PCA register.

Independence is what changes the value

Here the common framing gets it wrong. Being on the WDS register is an individual competence, and plenty of capable Waterproofing Design Specialists work for contractors and suppliers - the register certifies the person, not the company. What changes the value to you is independence. A specialist with no tie to a product or an installation has a single incentive: specifying what the building actually needs. When the same party also sells the system or wins the install, the design quietly bends toward what they supply - the “free” design becomes a sales instrument that favours their system, rarely interrogates the alternatives, and carries the true cost of free design in latent risk. An independent specialist is paid only for advice, so there is nothing for the specification to bend toward except the right answer.

The next step up: a design professional, not only a design specialist

The WDS register certifies waterproofing design competence. The strongest appointments add a second layer on top of it: a specialist who is also a chartered design professional - RIBA, RICS, CIOB or CABE - usually backed by a relevant academic grounding in engineering or design. That matters because waterproofing is never designed in isolation. It lives inside a wider design team and a formal design-development process, and a chartered professional has been trained in and works fluently within it - the RIBA stages, coordination with the architect and structural engineer, the information exchanges, and the discipline of designing to a brief and a programme. Waterproofing competence tells you the design will be technically right; professional design membership tells you it will be developed, coordinated and defended properly alongside every other discipline that has to build it.

Naming the role is the point

The single most useful thing a project can do is name a WDS and write the role into someone’s appointment, early, with the competence requirement stated. That converts an assumption into an accountability. Without it, the structural engineer often absorbs the risk by default without the competence or the professional indemnity to carry it, and the first time anyone confronts the gap is during a dispute. Naming a competent, independent owner is cheap; discovering at handover that nobody held the role is not.

Not sure who on your project holds this role? Put your scheme to the Waterproofing Wisdom agent, CLW’s specialist AI trained on BS 8102:2022.