Queensland: Assessing Renovations

Region: Qld

Assessor Question:

I am based in NSW but have recently had an enquiry about assessing a renovation in Queensland as the client is looking to renovate to improve energy efficiency and increase the size of the existing home.

Can you please advise what the requirements are for NatHERS assessments on Renovations in Queensland.

Are NatHERS assessments required for renovations over a certain price threshold like NSW or are NatHERS assessments only required for new builds?

If NatHERS assessments are required, are there any special rules I need to adhere to specifically as it is a renovation?

TechLink Response:

In answer to your specific questions:

• No price threshold is relevant, it’s whether the work requires building approval via local council or building certifier.  Most work requires building approval.
• For a NatHERS Assessment on a renovated dwelling, the only rules that apply are those within the NatHERS Tech Note, which state that the whole building needs to be assessed (Part 2.3, NatHERS Tech Note June 2019)

Generally speaking, additions or major renovations are usually assessed via the DTS provisions, with only the new elements requiring assessment.  

Note the following:

• If the dwelling achieves a nominal credit via MP 4.1 A1 (8), then the BCA 2009 DTS provisions can be used
• If the alteration is greater than 50 per cent of the floor area of the existing house, the building certifier may also require the existing parts of the house to comply with the 6 Star requirement (or DTS equivalent) where practicable

Further:

Building work in Queensland is administered by the Qld Development Code MP 4.1 – available here.

You’ll see in Part 3 (Application) Table 1, that Renovations of a Class 1 building need to comply with Performance Requirements P1, P3 & P5.

P1 states that the thermal performance of a class 1 building … must comply with performance requirement P2.6.1 of the BCA 2010 (Volume 2).   It then gives the option of compliance via a NatHERS Assessment, Deemed To Satisfy – Elemental Provisions (DTS) or VURB.  There is no further guidance in this document regarding renovations.

The “Queensland Development Code Mandatory Part 4.1—Sustainable buildings guideline” (May 2011) document is unavailable online at the moment.   However, Section 5.3.4 of this document states that the “The area of the home which is being altered and involves new building work that is the subject of the building development application, must comply with the 6-star housing requirement as far as practical”.   Under section 81 of the Building Act 1975, the building certifier has discretion to apply the energy efficient provisions to only the new building work or to the entire dwelling, depending if the requirement is considered to provide a level of benefit commensurate with additional cost or is considered as overly onerous or technically impractical.