Building in a Bushfire Prone Area

This Fast Fact outlines the requirements of the:

  • rfs-logo

    NSW Rural Fire Service (RFS) for the types of timbers permitted for exposed supports, posts and beams for buildings located on bush fire prone land in NSW;

  • bal-logo

    Bushfire Attack Level (BAL) 40 requirements for Fascia and Bargeboards.

Timber Supports, Post and Beams

Specifically:

1

Timber posts supporting the roof load only and not supporting a deck;

2

Exposed timber beams supporting the roof load only;

3

Timber posts and exposed beams which are purely decorative and offer no structural support to the dwelling;

4

The use of glue laminated timber members constructed out of a bushfire resisting timber (such as Merbau) for BAL levels requiring bushfire resisting timber posts, joist, bearers, and similar elements.

AS3959 (2009) – Construction of buildings in bush fire prone areas does not specifically address the issue of exposed supports, posts and beams for such applications. As such, there is a need to adopt a practical approach to the matter and ensure that the intent of AS3959 (2009) and the NSW document Planning for Bush Fire Protection 2006 is applied.

Applications #1, #2, and #3

In determining the type of timber appropriate for the building components, the requirements of AS3959 (2009) and Addendum Appendix 3 of Planning for Bush Fire Protection 2006 for exposed supporting timber posts and beams for other components of a building have been considered. Therefore, the NSW RFS provides the following advice in regards to the applications described in #1, #2, and #3 above.

BAL 12.5, BAL19, and BAL 29

  1. Non combustible;
  2. Bush fire resisting timber;
  3. Combination of a) and b)

BAL 40 -

  1. Non combustible;
  2. Comply with 1530.8.1;
  3. Combination of a) and b)

BAL FZ

Performance based – Generally, non combustible construction materials are permitted. Materials that comply with 1530.8.2 and do not support flaming are also considered appropriate.

In determining the type of timber appropriate for the building components, the requirements of AS3959 (2009) and Addendum Appendix 3 of Planning for Bush Fire Protection 2006 for exposed supporting timber posts and beams for other components of a building have been considered. Therefore, the NSW RFS provides the following advice in regards to the applications described in #1, #2, and #3 above.

info-iconPlease note that the above requirements are deemed necessary regardless of whether the timber supports / posts / beams are load bearing or non-load bearing. These requirements attempt to mitigate the ignition of timbers and the spread of fire to other building components (e.g. windows, eaves, roof cavity etc) as well as addressing any issues associated with structural integrity of the building when exposed to bush fire.

info-iconIn the opinion of the NSW RFS, the above measures will ensure that the requirements for exposed timbers as per AS3959 (2009) and Planning for Bush Fire Protection 2006 are applied consistently and that building occupants are provided with what is currently considered best practice bush fire protection.

Free Consultation

Glue Laminated Members

  • The NSW RFS is unaware of any research on the bush fire performance of glue laminate timber members that consist of bush fire resisting timber. It is the opinion of the NSW RFS that this type of construction material is not currently recognised as a bush fire resisting timber due to the composite nature of the materials and possible break-down of the glue.
  • A performance based solution should therefore be undertaken in such situations. The performance based solution will need to demonstrate that the glue laminate timber can perform as well as one of the recognised bush fire resisting timber species. It is recommended that testing in accordance with Appendix F of AS3959 (2009) form part of any performance based solution.

BAL-40 Fascia and Bargeboards

  • The RFS has become aware that limited, if any, testing of products for suitability for fascia has occurred.
  • Following a review of AS3959-2009 and the provisions for BAL-40, it is the opinion of the RFS that, as an interim measure (until further testing in accordance with 1530.8.1 occurs), the requirements for external walls (section 8.4 of AS3959-2009) are considered appropriate for fascia and bargeboards.
  • Should you wish to obtain a second opinion on these matters, the NSW RFS would encourage you to contact Standards Australia directly.

For further informationregarding bush fire protection measures, please contact
Development Assessment and Planning on (02) 8741 5175.

Schedule Your Obligation-Free Onsite Consultation

Simply enter your contact details below, and a Design Consultant from Pergola Land will call you to arrange a time to meet and discuss what you'd like to do with your space and what kind of pergola you'd like

 Yes No