How roller doors fail in a cyclone
The clearest evidence comes from Cyclone Yasi in Queensland. The Cyclone Testing Station's report found that many roller doors first came out of their side guides, then came off the drum and became wind-borne debris. Doors with wind locks, which anchor the curtain's edges to the guides, did better.
Some doors with wind locks still failed, mostly by tearing the guides away from the building. The report's lesson is that the guides, and the structure behind them, have to be built for large sideways forces too.
What a wind-rated roller door looks like
Each maker does it a little differently. Steel-Line's wind rated door has moulded lugs on the curtain that interlock with shaped side guides, and was tested at the James Cook University Cyclone Testing Station against AS/NZS 4505-2012. B&D's Wind-Rated Roll-A-Door uses wind clips to hold the curtain to the frame, and Gliderol sells Storm•Safe cyclone-rated roller doors.
Reading a wind classification
| Non-cyclonic | Cyclonic | |
|---|---|---|
| Regions | A and B | C and D |
| Classes under AS 4055-2012 | N1 to N6 | C1 to C4 |
| Higher number means | Higher wind speed | Higher wind speed |
Motors and power cuts
Steel-Line's wind rated roller door opener package comes with two remote handsets, a wireless wall button and a battery backup unit. Plugging an opener into an existing power point is not electrical work under NT law, but a new power point needs a licensed electrician, who gives you a certificate of compliance within 20 business days.
Roller doors around Darwin
Fixings and rust
The NT Government's inspection guide says humidity, heavy rain and wind can loosen fixings over time, and corrosion is worst near the coast. Check the brackets and guide bolts every year.
Post-Tracy homes
Much of Darwin was rebuilt after 1974 to stricter cyclone codes, but a door may have been swapped since. Look for a wind rating on the door or in the paperwork.
Termites
The Territory is a high termite risk area, the NT guide says, so check any timber the guides are fixed to.
What we would do
If your roller door has no wind locks or clips and no rating you can find, ask for a quote to replace it with a rated door at the same time as any repair quote. Yasi showed roller doors were a weak spot in otherwise sound homes, and it is better to know the options before November.