Repair or re-waterproof?

A local repair can be sensible when the cause is isolated; widespread ageing or failed detailing can justify a larger scope.

When a local repair may work

A single failed penetration, drain detail or isolated puncture can sometimes be repaired if the surrounding system is sound.

When a larger scope makes sense

Widespread blistering, brittle membrane, repeated failures, saturated layers or failed terminations can make repeated patching uneconomical.

Diagnose first

Trace the likely water path and inspect the substrate before deciding. Interior stains alone do not identify the entry point.