Cyclonic Ratings for Buildings

Many customers ask to either purchase or hire cyclonic specification buildings but are often not aware of what is required in order to comply with the Building Code of Australia. Transportable buildings manufactured prior to the introduction of the BCA 2011 will more than likely NOT comply with current regulations due to amendments made to the Building Code of Australia.


Firstly the structure of the transportable building must be manufactured to comply with the wind loadings of the region to which the building is going to be located in. Region D cyclonic areas are the highest wind rating in Western Australia. In order to manufacture the building to comply with the required wind pressures the builder will have had to consult a structural engineer during the design process.


Once the building leaves the manufacturers premises it does not automatically comply with the regulations when it is delivered to its final destination. In order to withstand the wind pressures that may be placed onto the structure it will need to be ‘tied down’ to suitable concrete footings.

The design and construction of the footings is not generic and anyone suggesting that it is shall be supplying false and misleading information. A footing and tie down detail must be designed by a qualified structural engineer for your actual site location taking into account the building that you are intending to place on the site and the directions/orientation of the building.

Councils will not approve any building located in a cyclonic area unless a structural engineer provides the documentation and only ink original signatures on the documents from the structural engineer will be accepted. Usually three copies are required by the council.

Because of the above requirements the certification process must be carried out for each client and site where a building will be located. Once the engineer has provided this information it is then up to the customer to ensure that the footings and building are tied down in accordance with the design issued by the engineer.

Failure to comply with the engineers requirements will result in you being liable for any incident that may occur. You should not make yourself or your organisation liable by trying to take shortcuts in this process.


Many hire companies will not provide customers with the correct information as they either are not informed themselves of the requirements or they do not have the resources to assist the customer with these processes.

Only a Structural Engineer is qualified to make statement with regard to the suitability of a structure for placement in a cyclonic area and the design of the footings and tie downs.

Instant Transportable Offices can arrange structural engineers design and certifications for any buildings that it manufactures however the cost of an individual certification is not included in any hire arrangement that the company enters into. For an accurate cost to have this work performed for your project please contact a member of our team.