Cyclone study makes recommendations
Significant damage was caused by wind-driven rain during Tropical Cyclone Olwyn on March 13, according to the Cyclone Testing Station at James Cook University in Townsville.
It says properties in Exmouth, WA, experienced little structural damage in the storm because new buildings and those repaired after Tropical Cyclone Vance in 1999 performed in line with expectations.
However, many residents were left mopping up after wind-driven rain entered properties through flashings, windows and doors.
Damage was caused to plasterboard ceiling and wall linings and carpets and timber floors, and a substantial number of insurance claims are expected.
Homeowners put themselves at risk of serious injury by trying to deal with the water entering their properties during the storm.
There are a number of ways to reduce water ingress, the station says in a report.
“To remain effective, all surfaces of roof flashings must be anchored with at least the same fasteners and spacing of fasteners that are required for the adjacent roof.
“In high winds, flashings must also exclude upward-moving water, especially at valley gutters, ridges or flashings with walls.”
Windows should be rated to the appropriate site wind classification, and weep holes should prevent large volumes of water being forced from the outside to the inside of buildings.
Olwyn crossed the West Pilbara coast near Exmouth as a Category 3 cyclone, with gusts of up to 180kmh recorded.