Renowned architect, my professor in Europe, around 2005. The flat roof in Europe was a bit like parapet walls in New Zealand. Or "no-eave" design — everyone has an opinion about them.
He stood in front of the lecture hall and explained: all his large buildings in Germany, all his flat roofs, worked 100%. Not a single leak. Outside Germany, some of them leaked. The same design, the same details, the same specifications.
What changed? Not the architecture. Not the building code. The contractor.
He showed us a photograph. A contractor on a roof in some other country, distributing gravel over the waterproofing membrane on a flat roof... with a steel rake.
They didn't have the proper tools on site. They used what they had from landscaping. And they damaged the membrane. Water got in. The roof leaked.
But everyone blames the architect.
Flat roofs don't leak. Poorly installed flat roofs leak. And poorly installed anything leaks — pitched roofs, parapet walls, windows, claddings. Good detailing is the first requirement; good workmanship is the second. You need both.
One thing New Zealand does well is share experience and knowledge. We learn from each other's failures as much as successes. The trick is making sure the right lesson is learned: design matters, but so does the person holding the tool on site.
Whether flat or pitched, roof detailing is critical to a high-performance build. We design for both performance and buildability.
Get in TouchPreviously published on sips.network (2021). Updated for VILA.nz.