Roof Waterproofing in Sydney

What balcony waterproofing in Sydney actually involves

A flat or near-flat roof on an apartment building is not a simpler version of a pitched roof. It holds water by design for as long as it takes the falls to move it, which means the membrane, the upstand where it turns up the parapet, and the termination under the capping all have to work together. When one of them lets go, the water does not appear directly beneath the failure — it tracks.

What gets checked on a roof

Rooftop terraces make the same problem harder, because the membrane is under a wearing surface and cannot be inspected without lifting it. Outlets are the other recurring culprit: a drain that silts up turns a designed fall into a shallow pond, and a pond finds every weakness the membrane has.

Sydney's rainfall pattern is what makes this an autumn problem. Mean rainfall peaks in March and June and troughs in September, with June running at roughly double September at both Observatory Hill and Sydney Airport. A roof membrane that copes with a summer downpour can still fail under several days of continuous autumn rain, which is when the calls come. Source: Bureau of Meteorology climate statistics, Sydney (Observatory Hill) station 066062 and Sydney Airport station 066037.

Roof Waterproofing in Sydney — common questions

Why does the leak appear away from the damage?

Water entering a roof membrane travels along the fall of the slab or between layers before it finds a way down. The wet patch on a ceiling marks where it exited, not where it got in.

Can a rooftop terrace be fixed without lifting the surface?

Only where the failure is at an accessible junction such as an upstand or an outlet. If the membrane under the wearing surface has failed, the surface has to come up.

How often do roof outlets need clearing?

Often enough that a blocked outlet is one of the more common causes of a roof leak. A drain holding water instead of moving it is doing the opposite of its job.