The Fatal Flaw in Modern Waterproofing

I've been reading a lot of articles and posts on LinkedIn about waterproofing membranes, and the more I read, the more I feel there’s a major flaw in how we think about waterproofing. Maybe calling it a fatal flaw is a bit much, but hear me out.

The issue is that waterproofing is often treated like a stand alone system - as though nothing else existed or mattered. People focus on the membrane and the waterproofing system standards and compliance in isolation, but I think that's where we might be going wrong - with separate contractors, separate standards, separate qualifications and separate validation and sign off by the certifier. And yep I know there is a good reason for this - it sort of makes sense but sometimes it feels like we focus on the trees and forget the forest.

The real problem is that different elements are handled separately by different people at different times. Waterproofing is often done by one contractor, while drains, flashing, tiling, windows, balustrades, concrete - effectively everything around it is handled by others. But these components need to work together as one system to be effective.

The waterproofing industry does not help either - their marketing material points to premium waterproofing products as being the answer - but if you speak to anyone in waterproofing there is little difference in the quality of comparable spec materials between manufacturers  (assuming you use a reputable supplier). Most architects take the view - “Surely the most expensive system must be the best right?”

My experience tells me that very few modern waterproofing systems fail just because they degrade or are mechanically penetrated - it’s normally at the termination of other materials that it breaks down or water sitting or stuck in the wrong place, unable to get out.

I claim that waterproofing - to be effective - must be part of an integrated system. There’s no point just looking at it in isolation. Waterproofing is actually just one component of a bigger drainage system.

I always try to build a mental model and treat the whole system as a vessel that temporarily carries and moves water from one place to another. Then I like to ask awkward questions like; what happens when that drain is blocked, what happens when the timber shrinks and the steel expands in the summer and the reverse happens in the winter.

Until we start thinking of it all as one integrated system, we're going to keep having the same failures with water ingress.

What do you think? Let me know.

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