Repairing or Rebuilding after Tropical Cyclone Seroja

Build Back Better

Stronger tie-downs make your house more resilient - ask your builder to use them in your roof and walls.

If your roof structure is not well tied down, the roof could fail again in a future wind event.

A cyclone like TC Seroja could happen again.

roof restoration.
Photo used with permission from Kalamunda Roof Restorers

Contact Your Local Council

Contact your local council to check if you need building approval.

Compliance with building standards

All repairs and reconstruction must at least comply with the National Construction Code (NCC). Whether or not a building permit is required. Building and Energy Industry Bulletin 53 provides information on building permit requirements.

Replacing your tile roof with a metal sheet roof
The new metal sheet roof will be lighter than the tile roof, so stronger tie-down connections are needed in the roof and walls. See this video on replacing roofs on houses for more information.

The repairs or reconstruction need to be designed for the wind loads or wind classification for your house. A structural engineer usually does this and can also design the new or upgraded tie-down system.

Engage a registered builder. Check the fact sheet ‘Do I need to be a registered builder?’

Engage licenced contractors for other works

Disclaimer: The Cyclone Testing Station (CTS) has taken all reasonable steps and due care to ensure that the information contained herein is correct at the time of publication.

Damage Caused by TC Seroja

TC Seroja caused severe damage to many houses in the coastal areas of the Mid-West of WA.

A team from the Cyclone Testing Station (CTS) investigated the damage and prepared a report - Technical Report 66.

Many houses damaged during TC Seroja were designed to the appropriate wind Standards. However, in many cases, the roof was hanging on until a window or door broke, which increased the air pressure inside the house. The increased pressure on the underside of the roof added to the suction on the upper surface of the roof – the tie-down connections were not strong enough to cope with the increased pressures, and the roof was severely damaged or completely blown off the walls.

If you want your home to be more resilient in future cyclones, you should repair or rebuild with stronger connections – build back better!

This small investment in resilience means that in a future cyclone, there is a much higher chance that your house won’t lose its roof even if a window or door breaks.

damaged house.

Wind Regions and Wind Classifications

Western Australia is divided into 4 wind regions:

A, B, C and D. Wind Region A has the lowest minimum design wind speeds and D, the highest. Houses designed for Perth wind speeds are usually not suitable for Wind Region B.

Wind regions and wind classifications map

Houses are designed for the expected wind speed at the house site.

  • N classification for houses in Wind Regions A and B
  • C classification for houses in Wind Regions C and D

Houses built to C wind classifications require stronger tie-downs in the roofs and walls.

More details about Wind Classifications here.

Advice on Upgrading Your Damaged Roof

See our online maintenance and retrofitting guidelines for Australian houses called Weather the Storm.

Kalbarri, Northampton, Geraldton, Mullewa, Mingenew Three Springs, Carnamah

Wind Region B

A tropical cyclone is more likely to affect towns in Wind Region B than in Wind Region A. It is important that houses in Wind Region B are built back better.

Although your house will have an N classification, ask your builder to use tie-downs suitable for the equivalent C classification. Your house will be more resilient.

House with strong tie downs
Houses with stronger tie-downs will be more resilient.

Equivalent wind classifications

(the same design wind speeds, but stronger tie-downs)

N2 – upgrade to    C1

N3 – upgrade to    C1

N4 – upgrade to    C2

N5 – upgrade to    C3

Things to discuss with your builder

  • Wind classification for your house
  • Use tie-downs in the roof and walls that are suitable for a C classification rather than an N classification.
  • Install a wind-rated garage door
  • Install stronger door latches and hinges
  • Check that any new windows have the correct wind rating

Perenjori, Morawa, Dalwallinu

Wind Region A

The tie-downs for houses in Wind Region A must comply with the National Construction Code (NCC).

Decaying tropical cyclones can also affect towns in Wind Region A, so building back better still makes sense.

Things to discuss with your builder

  • Wind classification for your house
  • Consider using stronger tie-downs in the roof and walls than the minimum required by the NCC
  • Install stronger door latches and hinges
  • Check that any new windows have the correct wind rating

Maintenance

Regularly check and maintain your house so it is always ready to protect you.

For more information see the preparedness guide

Video on Replacing Roofs on Houses

Replacing Roofs on Houses

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