// Case #08

Overlapping tapes — but which way?

01Situation

At panel joints, it was unclear whether waterproofing tapes overlap — and what goes first: horizontal or vertical joints. Crew is to execute, clear guideline is missing.

02Where Margin Escaped

Wrong order or overlap in the wrong direction is a potential leak. Leak emerges after cladding is laid — rework means tearing off finished layer or a warranty claim.

03Root Cause

Ambiguous waterproofing detail is a defect that emerges after cladding is laid. That is, at the most expensive possible moment.

Technical Principle

Overlaps are laid shingle-style — so water runs over the overlap, not into it; upper element overlaps the lower. Minimal overlap usually ~5 cm, depending on system. At corners, water-shedding element remains continuous. Manufacturer's system sheet decides details — it is in system docs and needs looking into before work, not recreated from memory.

!How the Loop Closes It

Execution detail is a spec that must be unambiguous and available on-site before starting. In the system: manufacturer system sheet attached to task as required file — task doesn't start without it.

See the modules that close this loop

The membrane that everyone walked on

Work was done well. Then nobody protected it — and it stopped being done well.

Ten centimetres too high

Nobody checked what height the annex foundation should sit at. The whole rest of the building was already a consequence of it — including a hole in the roof, cut in the wrong place.