Hi there,
Welcome to Episode 19 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
In this episode I’m sharing a powerful mental tool that’s helped me to think more clearly about waterproofing design and the common pitfalls that lead to failure.
It’s called ‘Inversion‘, and the idea comes from Charlie Munger – Warren Buffett’s long-time business partner and a brilliant thinker.
Inversion is a simple but effective approach to problem-solving: instead of thinking about how to achieve your goal, you think about how you would achieve the opposite, and then make sure you avoid those actions. So, let’s try it!
Step 1: Define the Goal
It’s straightforward: We want a dry basement.
Step 2: Invert the Goal
What’s the opposite? A wet basement.
If I wanted to end up with a wet basement, what would I do?
This might sound a bit odd at first, but it’s actually a very practical way of exposing hidden risks and poor practices that can easily derail your waterproofing project.
What would cause a wet basement?
Let’s walk through a few of the common failure routes I’ve seen over the years.
These aren’t theoretical – they’re mistakes that happen in the real world, every day.
- Scope Gaps
If no one explicitly owns the waterproofing design – not the architect, not the engineer, and there’s no waterproofing specialist appointed by RIBA Stage 2 or 3 – then you’ve got a gap. And in that gap problems love to grow.
- Non-Specialist Design
An architect or engineer might decide, “We’ll just go with Grade 2 here and use watertight concrete – that should do the trick.”
Maybe it works, maybe it doesn’t – but without a specialist, it’s a gamble.
- Catalogue Design
This happens when you ring up a supplier and ask, “How should I waterproof my basement?” They will give you a solution based on their products – not your site conditions, ground contamination, water table, or any professional accountability.
That’s not design – that’s sales.
- Weak Specifications
Using a generic NBS clause that sounds impressive but lacks any real accountability is a fast track to confusion and conflict further down the line.
- Poor Tender Scrutiny
Tender returns often aren’t properly reviewed. One bid might be £10,000 cheaper than another – and that’s good, but does anyone know why? Is it lower because they’ve cut corners that could cost thousands more post-completion?
- Non-Specialist Contractors
Letting someone inexperienced install your waterproofing system? That’s asking for trouble. Poor workmanship is a leading cause of failures.
- Short-Term Thinking
Trying to save a little money up front can often lead to big repair bills later.
Waterproofing is one area where value engineering can be dangerously expensive in the long run.
- The Ostrich Approach
Thinking “It’ll be fine – we’ll deal with it later” is a common mindset. Delaying waterproofing decisions until the main contractor is appointed often results in rushed or mediocre solutions.
So, how do you get a dry basement? Simple – you avoid all the things that would result in a wet basement.
Closing Comments
This is the real power of inversion. It helps you to identify and remove obstacles to success. You identify what not to do – then take action to actively defend against those risks.
Waterproofing design is a specialist discipline that requires dedicated expertise.
If you’re designing a basement or planning a below-ground structure, make sure that a qualified waterproofing specialist is appointed early in the process. I’ve seen too many projects go sideways because of the mistakes I’ve listed above.
Thank you for reading, and if you need support with your waterproofing project at any stage – from design through to delivery – get in touch. We are always happy to help!
Many thanks,
Ben Hickman
Hi, and welcome to another episode of Waterproofing Wisdom.
My name is Ben, and this episode I want to talk about something called ‘Inversion’, which has come to me via someone called Charlie Munger, who is Warren Buffett’s sidekick.
And, it’s basically a tool that’s used to think through problems and to navigate them.
So, the approach is that we would want to define our problem – sorry, define our goal! -which in our instance is going to be we want a dry basement.
And if we then invert that…what’s the inversion? It’s a wet basement.
And then we think through – What if I wanted to achieve a wet basement on my waterproofing project? What are my routes to achieving a wet basement? How can I go about doing that?
Now, the challenge here is I really encourage you to be realistic. So, we’re not saying here that you’re going to go and become some sort of supervillain and visit sites and slash membranes! What I’m talking about is a more realistic – in my world, in my real world, sat at my desk – what are the things that would lead to failure? What are the things that would lead to a wet basement?
And here’s some things that I’ve listed out – but I’d strongly encourage you to try and do this for yourself.
Just take five minutes and think through – ‘what could I do in my real world that would accomplish a wet basement’?
So here are some things that I’ve listed out.
You might be happy with a scope gap, so that would be that the architect’s scope doesn’t include basement waterproofing, and nor does the engineers, and you don’t have a waterproofing specialist appointed at RIBA stage two or three. There’s just a gap, and hopefully someone will fill that gap, they probably will, and they’ll probably be kind and helpful – but there’s a gap – and within that gap, problems occur.
Non-specialist design – so that would be an architect or an engineer saying, well you know, I think we’ll be alright with Grade 2 in this area, and you know, watertight concrete is probably a good approach. That sort of approach, we see that create problems.
Catalogue design – by which I mean we go to a supplier, and we say, ‘Hey, I’ve got this basement, how do I do the waterproofing’? And it’s a design that just comes from – ‘here are all my products’, and doesn’t come from – ‘what does the site investigation say, is there any contamination, what’s the water table, and here are the professional appointment documents that give me recourse if you give me bad advice. All of that stuff.
Using a naff specification document – that would be something like just a standard NBS clause that says a whole bunch of stuff that doesn’t actually hold anyone to account.
Let’s not really scrutinise waterproofing in terms of tender returns, that’s a common area. Not many people would know what to be looking for in that tender return – well this one is £10,000 cheaper, but is that better?
If you let a non-specialist contractor do the waterproofing, the workmanship is likely to be a bit worse, that could lead to failure.
That sort of short-term thinking of – let’s scrimp and save the ten thousand pounds now, which might actually cost one hundred thousand pounds after practical completion. That’s a good recipe for failure.
The sort of ostrich approach of ‘Hey, it’s going to be main contractors D and B, I think it’ll be fine, let’s not think about it early doors’, just kind of kick the can down the road. Let’s not pick up any cost now, that sort of thing.
Leaving it to the main contractor, and…what do you come up with?!
It’s a thought process tool that can be used to think through how do I get what I want?
So, to recap, it’s how do I get what I want?
Well, OK, if I was to try and get what I don’t want, what are the things that I would do, and then defend against those routes of failure.
And obviously I would say this, but one of the best ways to do that is to go to an independent waterproofing consultant, fill the scope gap and have them do you know, really good design development, performance specifications, scrutinise the tender returns, all of that sort of stuff.
So, thanks for your time, and do get in touch if you need any help with waterproofing!