Waterproofing Wisdom – Episode 03 – Appoint a Waterproofing Specialist

Waterproofing Wisdom is our monthly snippet of thoughts/lessons learned/news. You can sign up here.


Welcome to this episode of “Waterproofing Wisdom” which discusses the appointment of a waterproofing designer.

This episode will be most relevant to developers and project managers but will also be relevant for those who regularly form part of a design team.

You can watch a 5 min video here or read the highlights below.

Waterproofing Wisdom

This past month we’ve done two design reviews and, on both projects, we discovered major flaws. The biggest cause of these failures, in our view, is the failure to appoint a waterproofing designer at the right time during the design development process (the beginning of RIBA Stage 3).

In one project a basement floor slab which needs to be waterproof has been specified as having induced cracks throughout (with no means to waterproof them). In the other a basement on a contaminated site has had inappropriate waterproofing materials specified.

When waterproofing designs come from someone who hasn’t been appointed this causes problems because:

  1. Clients and the design team don’t have recourse if the design is negligent.
  2. A waterproofing specialist without an appointment doesn’t have a proper opportunity to influence the design.
  3. A waterproofing specialist without an appointment is unlikely to have sufficient resources to develop a proper detailed design


Many of us have experience with basement waterproofing failures. They are expensive, they cause delays and reputational damage. One of the best ways of avoiding such failures is the APPOINTMENT a waterproofing specialist early during RIBA Stage 3 as recommended by BS 8102:2022.



Ben Hickman
Technical Director


Hello, my name is ben and waterproofing wisdom is just my monthly opportunity to share with you some lessons learned or experiences or important things about basement waterproofing and this past month our team has done two design reviews.

So that is someone else’s design the client’s asked us to check it and we’ve come up with two major errors on two designs that we’ve looked at so error number one was essentially this where the basement floor slab had some induced cracks and this is a fibre fill board that is entirely saturated across these floor slabs and so that’s a situation where basically the waterproofing design was being led by a supplier.

They were not informed about these induced cracks the floor slab does need to be waterproof and the structural engineer was thinking with a structural engineer’s hat and produced an entirely appropriate solution but forgot about the waterproofing and so it is poor coordination.

Lack of connection there situation number two is this where there is a type a waterproofing membrane that is white and we are looking at a penetration with some very bad workmanship and this brown stuff around here is a bentonite fillet system and then the site has contamination there are some volatile organic compounds it’s not an appropriate material specification it is wrong and again that’s waterproofing ground gas protection design that’s come from a supplier and the main reason why I think those have gone wrong and obviously there are several reasons but the main reason I think is that a waterproofing designer wasn’t appointed and BS 8102 which is the code of practice about protection of below ground structures against water ingress has recently been revised and it’s got this clause that’s highlighted a waterproofing specialist should be appointed as part of the design team so that an integrated waterproofing solution is created and in both the situations we’ve just looked at the waterproofing designer wasn’t appointed and they should be why well firstly recall so if the waterproofing design isn’t good enough you know if somebody’s appropriately appointed you can have recourse so you can sue them and you can claim on their insurance and you a design team client you’re protected and you know that’s what that’s about if you’ve got free advice out of the generosity of someone’s heart and there is no contract it’s much harder to have any sort of recourse if the advice given is bad number two seat at the table a waterproofing designer who hasn’t got an appointment is in a weak position and if they say something that’s unpopular even if it’s the best design solution if it’s too expensive or inconvenient for someone else in the design team that person might just not get invited to the next team meeting and so they’re it’s not fair on the waterproofing designer even if they’re very competent that they may well not be able to deliver good quality design because of the they don’t have a proper seat at the table.

Then lastly recourse that’s right resource which is you know often you get what you pay for and if you’ve got a free waterproofing design has that party really got the time and the resource to properly thoroughly do site investigations to attend all the necessary meetings to do the coordination to do site-specific designs and details and full reports and too often the answer is no so, I guess that’s my plea.

My plea is to appoint a waterproofing specialist at the right time and the right time is the beginning of RIBA Stage Three because waterproofing affects your spatial coordination if you’re an architect or an engineer and you get asked well I just can you just put the outline design and uh you know we’ll procure it through D&B so it’s not really your design risk I would just urge you to say no it’s not it’s not my design it’s not in my scope it’s not my expertise appoint a waterproofing specialist if you’re a

client or a project manager I just urge you to recognize the value of good waterproofing design we have all been involved in basements that have gone wrong and it causes delay it is expensive it causes reputational damage why not just appoint the right person at the right time.

So thank you for watching this episode of waterproofing wisdom if you want to talk about basements or waterproofing in general, I love talking about waterproofing so give me a call.

thank you very much

At CLW, we take the resposibility of a condition survey very seriously. Our specialist surveys are carried out by experienced, qualified surveyors.

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