Pinholes: the smallest defect that costs the most
A hole the size of a pen tip in the one layer that must not have holes.
In short: The most common waterproofing finding on our Box Hill jobs, and the least visible.
What a pinhole is
A break in the applied membrane about the width of a pen tip, usually a burst bubble in the coat or debris trapped beneath it.
Where we find them
Shower recesses, hobs, niches, entries and powder rooms. Sometimes several in a single bathroom on the same job.
Why they get past
They pass a glance from the doorway. Finding them means going over the membrane closely, with light, which takes time and is why it is a stage of its own.
What happens later
Water passes through, tracks under the screed and turns up as a damp skirting in the adjoining room a year or two after handover.
The economics
Closing a pinhole before tiling takes the waterproofer minutes. Finding it afterwards means removing tiles, screed and often the shower itself.
Written by the Owner Inspections team from inspections carried out in Box Hill. Licensed building practitioners, NSW Fair Trading licence 366177C.
