A deck is a flat surface capable of supporting weight, similar to a floor but typically constructed outdoors. Decks can be built on the ground, or they can be elevated. A deck may or may not be, connected to a building.

The safety of elevated timber balconies and decks should be a primary concern for any building owner.

“Encroachments” under the Building Code of Australia (BCA) are considered to be any construction between the external wall of a building and the allotment boundary other than a boundary adjoining a road or other public space, or the external walls of two buildings on the same allotment. A deck is not considered an unroofed terrace and is therefore not permitted as an allowable encroachment, whether combustible or not. Under the BCA, all decking must be a minimum of 900mm off an allotment boundary and at least 1.8m off of a building on the same allotment.

What is required?

All decking that proposes structural footings, stumps, bearers and floor joists require a building permit.

What information do I need for my Building Application?

  • Completed application form, either a BA1 or BA2 with all owners noted and the builder’s and applicant’s sections completed and signed
  • Applicable fees (please see fee schedule)
  • Certificate of design compliance (only if submitting a BA1 – Certified Building Application)
  • Site plan at a minimum scale of 1:200 showing:
    • Setbacks from the lot boundaries and all other buildings on the property.
    • Dimensions of the proposed structure
  • Elevations at a minimum scale of 1:100 showing:
    • Heights
  • Engineering details signed by a structural engineer showing:
    • Footing details
    • Construction details
    • Specifications
  • Types and sizes of all materials to be used
  • If the proposed deck is within 6m of a dwelling it may require a Bushfire Attack Level (BAL) Assessment if your property is located in a designated bushfire prone area. Check the Department of Fire and Emergency Services (DFES) Bushfire prone areas map to see if your property is located in a bushfire prone area.
  • Existing BAL reports used for the original dwelling can be re-used for a deck application, only if the report is less than 2 years old and doesn't have an expiry date noted.
  • Depending on the result of the BAL assessment there may be additional construction requirements to reduce the risk of ignition due to bushfire.

Will any other approvals be required?

In some cases, a Development Approval will be required prior to the issue of the Building Permit.

Please note that further information may be requested before a building permit is issued.

For further information, please contact Building Services on 9526 1111 or via email at