Registered Building Work Supervisor & their Role for Owner Builders – Risks and Advice

If you decide not to engage with a building company but instead become an owner builder and complete the work yourself, you must engage a Registered Building Work Supervisor or Private Certifier. This is due to legislative requirements as part of The Development Act 1993 and is enforced by local Council as part of their conditions. This supervisor is required to oversee construction of all building work to completion.


Supervisors Role & Fees

The role of the Building Work Supervisor is to ensure that all building work is checked regularly and ensure the workmanship is undertaken to the approved specifications, drawings and the Australian Building Code. This role is incredibly important as it’s the responsibility of the supervisor to certify that all building work has been completed correctly and prevent defective work. They are required to attend the site frequently to provide adequate supervision of trades and workmanship completed by either professional subcontractors or the owner themselves. At the completion of construction, a ‘Statement of Compliance – Development Regulations 2008 – Regulation 83AB’ must be signed by the supervisor. This statement certifies that the work has been carried out in accordance with the approved documentation and the provisions of the building rules.

The more work and risks required, the more time they will have to spend on site. The cost of engagement depends on several factors and should be commensurate of the work involved. To provide adequate supervision and ensure the job is completed properly they will need to invest adequate time depending on the intricacy of the build. The more complex the build, the greater the supervision required, and hence the higher the cost of the supervisor. The fee, while dictated by the marketplace, may range between 5-15% of the total building costs. A higher fee is expected should their role also involve engaging and coordinating subcontractors to complete building work.



When an owner builder engages individual subcontractors for work over $12,000, the subcontractor must hold building indemnity insurance. This also applies to the Registered Building Work Supervisor. This insurance covers all domestic building work for any non-completion or failure to rectify faulty work even if the contractor is declared bankrupt. Proof of insurance must be forwarded to the Council prior to commencing any stage that requires subcontracting. The Supervisor will also need to have professional indemnity insurance to cover any errors or negligence in their supervision.


Defective Workmanship & Defects

The responsibility for defects that occur during the building process is dependent on several factors. While generally the subcontractor who completed the work is responsible for their own work, the supervisor must ensure they carry out their checks to ensure the work was completed to standards and specifications. Hence, they will be the first point of contact to sort the defect and it’s the supervisor’s responsibility to resolve the issue and who will ultimately pay for the rectification. The building work supervisor may be liable to pay part of the cost towards the cost to repair/fix the defect if it was reasonable for them to have been able to prevent it from occurring in the first place.

Example: If a carpenter is putting up a frame and the supervisor wasn’t there, but while checking over the work before cladding takes place notices the defect, the carpenter must cover repairs. However, if the supervisor was on site and able to prevent the defect or failed to notice the defect during their checks and signed off that it was fine, then part of the blame is placed on the supervisor.




We have a registered building work supervisor in our office, please contact us on (08) 8223 3009 for assistance.

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Owner Builder: 5 Key Considerations

Getting Council Approval for Buildings

Registered Building Work Supervisor & their Role for Owner Builders – Risks and Advice