Waterproofing Wisdom – Episode 22 – Andrea’s Waterproofing Journey: Part Two

Hi there,

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Welcome to Episode 22 of our Waterproofing Wisdom series, content that will be especially relevant to Project Managers, Architects and Engineers.

What can joining a waterproofing consultancy teach an architect?

This is the second post in a series following our Practice Director Andrea’s journey as he transitions from architecture into the specialist world of waterproofing consultancy.

Andrea joined us about two months ago. He’s an experienced design professional with years of architectural training behind him – but like many architects, he’s never had formal education on basement waterproofing. That’s exactly why I thought documenting his learning curve could be useful for other professionals in the industry and anyone curious about how waterproofing really works.

You can watch the latest instalment of our vlog below by clicking on our logo, or read on for a summary.

So, what has Andrea learned so far?

1. Waterproofing isn’t a “fix” – it’s a strategy

The biggest revelation for Andrea has been the shift from viewing waterproofing as a product instead of a design strategy that should be considered from the very beginning stages of a project.

In Andrea’s experience, architects often view waterproofing as something that you apply at the end – almost like a fit-out item. You complete the structure, and then you “waterproof it”.

But basement waterproofing doesn’t work like that.

“It’s not a system you bolt on to solve a problem. It’s part of the journey. It needs to be considered from the very beginning—loads, tolerances, concrete sequencing, maintenance, everything.”

Instead of thinking “How do I stop water getting in?”, he’s now thinking: “How will this building behave in its environment? How do we manage the relationship between the structure and the surrounding ground?”

That design-first perspective is crucial.

2. Basement waterproofing is a specialist subject

In his years of architectural training, only a tiny fraction touched on waterproofing. And when it did, the focus was on envelopes – roofs, façades, walls. Even foundations were lightly covered. Basements? Almost never.

“They teach you how to manage rainwater. Not how to manage a water table.”

So when Andrea began designing basements as an architect, how did he learn? By phoning a waterproofing supplier and asking for advice.

3. Supplier advice IS helpful… but not always holistic

Suppliers generally give good advice—but their advice is shaped by the products they sell.

Andrea looked back at one of his own historic basement details: a lightwell where the solution recommended to him included: • waterproof concrete • cementitious slurry • anti-lime treatment • cavity drain membrane • plus various protection layers

It worked – but it was over-engineered for a lightwell that only ever sees rainfall. “We created a perfectly sealed pool for something that didn’t need it.” This wasn’t because the supplier was wrong—they offered a solution that would work. But they didn’t know the whole design context, and it wasn’t their job to. That’s the gap that specialist waterproofing design fills.

4. The cost of too much “free” advice

When suppliers design the waterproofing, the advice is “free”- but the construction cost rarely is. Adding unnecessary layers might feel safe for the architect (and suppliers understandably won’t under-engineer), but on big projects those layers add up quickly.

Independent design can strip back what’s unnecessary, while still delivering robust performance.

5. The forensic side is surprisingly rewarding

One of the things Andrea is enjoying most is the investigative side of the job – working on buildings where waterproofing has already failed.

He’s fascinated by: • reading as-built details (or trying to…) • digging through O&M manuals to find what was supposed to be installed • comparing that with what actually happened on site • spotting where sequencing or detailing went wrong

We recently visited a house where we eventually found the “waterproofing design” buried in the O&M file – a single A4 sketch.

That experience taught Andrea how crucial early, coordinated design is – and how expensive it becomes when it’s missing.

6. Seeing the bigger picture

“Not bringing in a waterproofing specialist early may save consultant fees, but later you pay far more in remedial works, delays and disruption.”

Andrea is starting to see the bigger picture;

poor design → failure → disruption → remediation → lessons learned

And that understanding is already making him a better designer.

Closing Comments

This early stage of Andrea’s journey highlights something we see all the time: waterproofing isn’t difficult – but it’s misunderstood. It’s not an add-on. It’s not a product. It’s a co-ordinated design discipline that needs to be considered from day one.

If you’re following this series and you’d like Andrea to talk about something specific-his first site investigation, his experience with suppliers, details he’s now reconsidering – let us know. We’d love to cover your experiences and questions in a future edition.

Many thanks,

Ben Hickman

Alright.

Hi, my name’s Ben. I’m the Technical Director of CLW, and we started a series where we’re doing some something of a video log where I wanted to try and record Andrea’s journey.

Andrea is our new Practice Director, and he’s come from an architectural background and he’s doing this journey into the world of kind of niche waterproofing consultancy.

I think it’s fascinating that – obviously Andrea is a competent professional, like many others that we work with – I thought it would be interesting to see his insights as he gets more and more into waterproofing; ‘What is it that he’s learning, discovering, what are his reflections on how he’s done things in the past as an architect?’ That sort of thing. So, we’re still trying to find our way, I don’t know how useful this will be to lots of other people, but I think it would be interesting to many architects and engineers and project managers. So, Andrea, thank you, thank you for joining us again, thank you for sharing your journey. I thought maybe a good question to start with is… since the last time we did one of these, what’s the biggest thing that you’ve learnt about basement waterproofing?

OK! Thank you, thank you so much. But again, I’d just like to make, what do you say? I think it’s useful, not just for ourselves, but actually to share my experience and my view as an architect entering the niche of waterproofing.

So, what I’ve learned…now it’s been, I think like almost two months, two months, and a half that I joined CLW, and I have to admit I’ve learned a lot. In terms of biggest waterproofing realisation so far, I feel that as architects that we tend to see the waterproofing as a system to solve a problem, where more and more, I appreciate actual waterproofing design. It’s part of the strategy, and it’s something that is not there to be applied to complete something. It’s actually part of the journey, part of the design. This is why it needs to be taken into account at early stage. When you start to take into account – for instance – like load, or for instance, tolerance, or concrete sequences.

Just because waterproofing is not – a fit out object – but needs to be taken into account during, and also after, and also you have to maintain, you have to understand how to maintain, how to…again going back to the sequencing, how to approach the sequencing, taking into consideration the waterproofing. So, I think like this is the biggest thing so far that I needed to learn.

Yeah. I like that. I think we often – I often – get the sense that waterproofing is something of an afterthought, it’s just ‘do everything else and then go and slap some paint or something and then it’ll be waterproof’.

Yeah, absolutely. It’s like if you imagine waterproofing as a bespoke product to solve a problem of water. When instead like waterproofing design, it’s actually wanting to coordinate and manage. Not just a problem. Manage simply the surrounding of a building. So, if you mention your box, and your box you just like imagine your basement, you submerge into a pool. You have to understand how the context will go on a reactor and behave with the building.

So again, you’re not trying to find the solution. Try to understand how to make this building behave with the context – so it’s poor management and coordination.

Yeah, that’s great. We spoke about – you showed me even a waterproofing detail that you’d developed when you were an architect – tell me about what, what is that like as an architect? Because my assumption is you go to university, you do seven years of study or whatever, but I would assume that none of that covers basement waterproofing, and then you become an architect, and then somehow it gets into your scope that you’ve got to do the waterproofing. How do you do that? How do you know how to do the waterproofing?

So, if we make a step back, there as an architect during my journey, the first bit that I got familiar to waterproofing, it’s almost like a tuning, you learn how to waterproof your envelope from outside. So, you start to understand how to apply waterproof to the roof, to the walls – maybe – it depends on how good your course is. You understand how to waterproof the foundation. However, they almost never talk about basements, how to waterproof a basement. or even if you want to touch base on the basements, they don’t really explain how.

Because the problem with waterproofing the basement is not the basement per se, but it is of course again going back to the context – how to learn to read the context. This is so that you understand how to manage rainwater fall but not actually how to manage the water table from the ground.

When I start like working as architect of course like you start to get familiarised in waterproofing, start to prepare your own details. So sometimes the walls, and that’s the rule for when it comes to basements. The only way that I learn how to design my details, it’s either through experience – so learning from a more experienced architect than me, or even like learning from expertise from site, otherwise like the most common route is going through a supplier. So, you call a supplier, and you say OK, I have this one [project], I need to waterproof my basement, what do I have to do?

And the supplier, of course, they are specialised on their own products, meaning that they will tell you, ‘OK, you have to put in this barrier to put in like a membrane, you have to put this one in to make the space dry. Fine. I trust you because you tell me what I have to do.’ Of course, I will do my diligent research. I might do a comparison with other companies.

But pretty much of course, you rely on the supplier expertise. This one, as you can imagine, relies on supplier expertise. Especially if you’re not a specialist.

It means that you kind of trust that that system works because they guarantee the system. Now, the issue that I’ve found like so far in many years of my experience, it’s not that it’s bad advice that they give you, sometimes it’s over engineered, or might not take into account in a holistic way, the use of the space. So yes, the details that I was showing was like in that specific case was the section details of a lightwell and the windowsill, and then there is of course the basement room, bedroom. In that specific case, looking back on the details, I’ve seen that I followed the instruction, which was like using concrete at the time, just concrete. There was no real knowledge, or at least as architects, of the waterproofing concrete, at least not back then, and then I would apply slurry, perhaps like anti-lime products, so slurry and then a membrane – a drainage membrane.

Now, looking back, although this piece of my work was in a totally dry environment, in a bedroom, perhaps it’s not the best place to use in a lightwell. Not because it’s not useful, it’s not like it’s incorrect or it’s wrong, it’s just because it’s over-engineered for the use. It’s a wet space, so why have to use so much like, layer protection, where actually it might not be necessary? Again, this is not a comment or critique, to the supply company who recommend the details, it’s just perhaps going for a more independent approach, I might get the same solution, which actually would work better in terms of like cost and time on site and still achieve the same performance.

Yeah. So, in that situation, you went to a waterproofing supplier and they said, do all of this in a lightwell, so you got a lightwell, with a concrete, slurry cavity drain membrane. But it’s just rain falls on it.

So basically, we create like a pool, a perfect seal pool. Now I understand that looking back, of course like when you take on board these kind of details you want to make sure that there are no doubts, there is zero risk, especially because as architects you don’t want to take risks, so even if you have to over engineer, you’d rather take overengineered and tested to have like the minimal chance of risk. I do appreciate that especially like in a small project, you tend to over engineer, and to be honest, if it’s in a small project, perhaps that one, ultimately the cost of saving is not huge.

However, when it comes to a project, a commercial project like a £100 million development. In that case a different strategy which allows it to reduce by perhaps one layer, perhaps it’s a good saving in the long-term.

Yes. Yeah, I think what you describe as a classic example of cheap or free advice turning out to be expensive because essentially the design advice is ‘use my product, and this other product, and this other product’, and you just didn’t need to.

Yes, on this point, it’s again as any other like supplier. They’re very expert, their expertise is on what they’re selling, what they do. And don’t get me wrong, I believe what they sell – all the details, that works.

Although what then? What’s happened? As an architect then you take the details and then it’s up to you as the architect to understand how the details coordinate with the rest. Because the detail per se, works well on its own. But then you have to understand how it reacts with other products, how it reacts with the environment? How it reacts with, or how it needs to be sequenced on site – so all of this is something that you learn over experience, or you of course rely on a waterproofing design.

That’s great. OK, one last question then. What are you enjoying most at the moment, working at CLW – or being in this industry even?

OK, first of all, the projects actually! The projects that CLW works on are great projects. At the moment very exciting projects, which we cannot disclose too much, but quite nice sites in central London.

And I think I’m enjoying the most – seeing how things failed.

I’ve noticed that part of our projects, or anywhere like works comes from previous waterproofing design installed which then failed or strategy which then failed. So, they call us to understand what went wrong, and how can we fix it?

And again, this one I guess we go back to the first steps. It’s like waterproofing is not a solution. It’s supposed to be part of the overall picture and the coordination since the beginning. So, it’s tricky to work with some issue at that stage.

Although I think like this to go back to your question, what I’m enjoying the most, it’s seeing this kind of circle of issue; not taking on board the waterproofing specialist at early stage which then perhaps saves you a bit at the beginning in consultant fee, but then later stage, perhaps the consultative fee would be still the same, but what you as an investor spend the most is actually on major remedial works, which uses up a lot of spare time, a lot of headaches! So, I think that was what I’ve enjoyed the most, like seeing, understanding, and feeling and recognising those things – which, ultimately makes me – I cannot say that I’m a waterproofing specialist right now! – but a better designer, yes.

That’s good. Absolutely. That’s great. Yeah, I agree. I think the forensic engineering, the looking at what’s gone wrong, I think one of the things I really wanted you to see was, you get to site and you’re trying to figure out what the ‘as build’ detail is, and then you start going through the O&M manual to try and find ‘what is the waterproofing?’, and we were on that house together – and we go through one folder and there’s like ‘no, there’s nothing here’ and then we get to the other folder, and we’re like ‘found the waterproofing!’ and it’s just this sketch.

It’s an A4 template and say OK yes, it’s been installed!

Yeah!

So, I just think that’s such a help. I wish every design professional in construction had to go and do that twice a year or something, so that they realise what goes into the O&M manual has to make sense.

I finished a project back then – I think like six years ago, and this one was a beautiful townhouse in central London, and you can see after, you know there is a normal like defect time which it comes, like perhaps it’s some finish, or some joinery or something like that. And we’re discussing at the time and say ‘yes it would be nice if an architect, anyone who built or is in a construction industry lives in that place for at least six months to recognise a lot of what went wrong, what could have been done better actually? So, I don’t know perhaps away of approaching, like sequencing or like somehow to install, or a lot of things.

Very good. That’s great.

Andrea. Let’s leave it there. Thank you. Thanks for sharing and your honesty and authenticity. I hope this is useful, if you are watching this and you think ‘I wish Andrea would talk about ‘XYZ”, it’d be great to hear from you.

Thanks.

Thanks Ben.