Waterproofing Wisdom – Episode 20 – When to Pay for Waterproofing Design

Hi there,

Watch the episode on YouTube

Welcome

Welcome to Episode 20 of our Waterproofing Wisdom series, content that will be especially relevant to Project Managers, Architects and Engineers.

You can watch the short 5-minute video below, or read on for the highlights.

Introduction

Today I want to tackle a common but often misunderstood question in the construction world:

When should you actually pay for waterproofing design?

It’s a fair question, and one that clients, architects, and contractors ask all the time. The short answer? You’re going to pay for it one way or another – whether that’s upfront, or further down the line when things go wrong. Let me explain.

The Temptation of “Free” Design

In the early stages of a project – say, around RIBA Stage 2 – it can feel premature to commit budget to waterproofing. After all, you might not even have planning permission yet. That’s why many teams try to place the waterproofing design into the architect or engineer’s scope, who may then turn to a product supplier for some ‘free’ input. While that might sound cost-effective, most of the projects we work on eventually go down a design-and-build procurement route. So, even if there’s a conceptual design at the start, the details are usually left to the contractor to resolve.

But here’s the catch: contractors aren’t taking on that design risk for free. They understand the liabilities and risks involved, and they build that into their pricing. Whether it’s a “risk fee” or inflated costs buried in the build price, the client ultimately ends up footing the bill.

Free Isn’t Free

Even when a waterproofing design is supplied at no cost—say, by a product manufacturer—that design still comes with costs. You may not see them immediately, but they surface later as increased risk, poor coordination, or expensive mistakes.

So the better question to ask is; “If I’m going to pay anyway, what am I actually getting for my money?”

The Two Big Risks of Avoiding Proper Design

There are two key risks we see time and again when waterproofing design is left to chance or squeezed into someone else’s scope.

1. Poor Design

This is the obvious one. A design that’s not well thought out or properly coordinated can lead to leaks, delays, and huge remedial costs.

I’m currently advising on a case where a contractor is facing a payout of over four hundred thousand pounds. Why? Because the basement leaked, the tenant lost rental income, and now the contractor is chasing the supply chain trying to recover the losses. Nobody wins in that situation.

2. Sales-Driven Design

This is subtler, but just as dangerous. Sometimes a waterproofing supplier offers to design the system at a low cost—or even free—but their primary goal is to sell their products , not ensure the best outcome for the project.

In one recent project, the contractor proposed changes to the waterproofing approach that didn’t align with our original design. The cost manager flagged it, and we were able to confirm that those changes weren’t needed – and saved our client nearly half a million pounds.

Without an independent expert on board, that kind of value would’ve been lost.

Are there Exceptions?

Yes—sometimes. If you’re doing something like a residential basement conversion and you’re turning the space into a basic utility room, you may not need a full design team.

In these cases, I recommend going directly to a specialist waterproofing contractor. But be selective: look for companies that are members of the Property Care Association (PCA). Their members are audited, financially sound, properly insured, and capable of offering meaningful guarantees.

Closing Comments

So, when should you pay for waterproofing design?

• If your project is complex or involves a basement: early design input pays off.
• If you’re trying to avoid cost by relying on “free” advice: understand the hidden risks.
• And if you’re working on a small, simple residential job: a competent specialist contractor may suffice.

At CLW, we’re passionate about helping our clients make informed decisions and avoid costly mistakes. If you’re unsure about the right approach for your project, feel free to get in touch—we’d love to help.

Thanks for reading!

Many thanks,

Ben Hickman

Hello, and welcome to Waterproofing Wisdom.

My name is Ben and I’m Technical Director here at CLW.

Today I wanted to talk about ‘When to Pay for Waterproofing Design.’

And I guess my starting point would be…you will end up paying and that could be paying somebody like ourselves, from RIBA Stage 2 – that’s obviously an expense upfront, and sometimes you’re expending money before you’ve even got planning. So, a lot of people like to avoid that.

And another option is that you might lump in the waterproofing design within the architect or engineer’s scope, and frequently the architect or engineer would go out to a product supplier and get some free input.

Most projects we work on end up being procured through design and build, so ultimately, you know, you can do a kind of conceptual design and push it to the contractor.

I guess the issue there is that you incur on the cost through a risk fee, or it’s some other cost.

Contractors are not foolish; they understand the risk and therefore are going to pass on that cost to the client.

And I think what’s important here is if we acknowledge that even the FREE waterproofing design options cost, then it’s important to consider – well, what do I get for my money?

How much does it cost, and what do I get for my money?

I think there are two really, really big risks that I’ve come across when we see waterproofing design by stealth, or sort of the ‘the ostrich approach’ of – I don’t really want another consultant on the team, I don’t want to incur more consultant fees, it’s going to be design and build anyway, let’s just push it to the contractor.

And I think the obvious one is, is the first one, which is poor design.

So currently I’m an expert on a case where the main contractors had to pay out four hundred and something thousand pounds. They handed over the basement, it leaked, there was loss of earnings from rental income, all that stuff, and the main contractor is now going to the supply chain trying to recoup that cost.

But that’s not fun for anyone.

So there is a really obvious risk where if you pay very little for a waterproofing design, it’s often badly coordinated, badly put together and the cost of poor design can be very, very considerable.

The other is when the designer exploits their position, so frequently you’d get a waterproofing supplier who either for free, or at very low cost, will design a waterproofing solution in partnership with the architect, but they normally don’t coordinate anything and it’s often very weak design without much thought.

But in that situation, what you can see is that the designer is exploiting their position because they have sales targets.

And so we had a situation recently where the cost manager that we’re on a project with gave us a call and said the contractor’s asking us or saying that they need to do this. That doesn’t really match with your waterproofing design, what’s the situation?

And we were able to help explain, look, we don’t need to do waterproofing there, that’s irrelevant – and we saved our client nearly half a million pounds on that.

And so, you can if you, if we just try and hide from waterproofing design, there are costs that we don’t notice that can really, really add up.

Are there any exceptions? Well, sort of, and I guess I just wanted to point out, look, if you’re doing a basement, a residential basement conversion, or something like that, and you just want your utility space in the basement, you probably are better going direct to a specialist waterproofing contractor who can design and install and guarantee their work.

And in that situation, I recommend you visit the Property Care Association. All of their contractor members are audited, they’re in good financial standing, they have access to guarantees, they have insurance, they’re competent.

So, there’s my quick take on basement waterproofing design, and when to pay for it, and how if there’s anything that we can do for you, do give us a call and we’d love to connect!

Thank you very much.