(1)  This section applies to building work performed on a building if, within the previous 3 years, building work has been performed or permitted on more than half of the original volume of the building.

(2)  If building work to which this section applies is performed on an existing building, the owner of the building must ensure that the entire building, as part of that building work, is brought into compliance with this Act and the applicable provisions of the National Construction Code.

(3)  The building surveyor, engaged in respect of building work to which this section applies, may consent to partial compliance with the applicable provisions of the National Construction Code in respect of the work if the building surveyor is satisfied that the partial compliance is appropriate, after taking into account –

(a) the structural adequacy of the existing building; and

(b) the requirements necessary to make reasonable provision for –

(i) the amenity of the building and the safety and health of the people using, or intending to use, the building; and

(ii) appropriate measures to ensure that fire cannot spread to, or from, any adjoining building; and

(c) whether the building is a historic building.

(4)  The relevant building surveyor must not consent to partial compliance under subsection (3) in respect of building work on an existing building to which this section applies, if that work involves the extension of the existing building –

(a) where the floor area of the extension exceeds –

(i) 25 percent of the floor area of the building before the commencement of the extension; or

(ii) 1 000 square metres; or

(b) that a determination of the Director of Building Control makes ineligible for partial compliance under this section.

(5)  Nothing in this Act requires a building that is not the subject of work under this Act to be upgraded to comply with the National Construction Code unless the building is the subject of a notice, or an order, under Part 18 .