Determination 2016/048 – Summary

Posted: 9 December 2016

Determinations
The determination concerns construction defects that were exposed during building work undertaken to remediate weathertightness issues to an apartment building.

The determination considers the code-compliance of the use of intumescent sealant without plasterboard patches for penetrations in intertenancy walls, and discusses the application of section 112 of the Act in respect of the defects in existing construction including those not exposed as part of the proposed building work. This article summarises the determination findings regarding section 112.

The matter to be determined was whether the building consent authority (BCA) correctly exercised its decision powers in accordance with section 112(1)(a)(i) in requiring all of the penetrations and gaps in the intertenancy walls to be remediated, including those not exposed during the consented alterations, and whether the proposed solution using intumescent fire sealant without plasterboard patches would comply with the Building Code.

The building work and background

The property is an existing development of 56 three-storey terraced town houses, in four blocks. The fire rating between the adjacent units is achieved with a mix of conventional fire-rated plasterboard lining to timber framing, and solid timber blocking above the wall framing. The units have Type 1 smoke alarms in the bedrooms and above the landing on the building's third level.

In 2013 the BCA issued a building consent for alterations to be carried out to address weathertightness issues (the planned works). While these alterations were being carried out, construction defects in the intertenancy walls were discovered. These included unsealed cable penetrations and framing gaps within the intertenancy walls. The BCA held the view that in order to comply with section 112, all of the defects required remediation, despite the fact that this work was not included in the scope of the building consent. The consultant for the owners was of the view that it was not “reasonably practicable” to remediate all the penetrations and gaps, but instead remedial work should only be carried out on the areas that were exposed as part of the planned works.

Discussion

The application of section 112

When a building consent for an alteration is lodged, section 112 of the Act requires the BCA to make an assessment of the building’s compliance with the building code, after the alterations.

In this instance there was a dispute as to whether the remediation of the underlying construction defects were included within the scope of the building consent, which was issued to address weathertightness issues, and also whether the BCA could require remediation to all of the intertenancy walls rather than only those areas uncovered as part of the planned works.

Scope of the building consent and whether the BCA can require remediation to the whole of the intertenancy walls

The authority has limited power under the Act to require remediation of original construction work that has been issued with a code compliance certificate. That said, the authority can address remediation of the original construction work where the code compliance of the subsequent alterations or new building work relies on the original construction work (for example the building’s existing structure must provide adequate support for any new structure).

At the time the building consent was lodged, the existing defects to the intertenancy walls were not apparent. The remediation of the unknown defects was therefore not included in the scope of the building consent. However, once the defects were uncovered, it became apparent that the building, after the alterations, would not comply with the Building Code in respect of means of escape from fire. At this point, in such circumstances, the BCA may issue a site notice or a notice to fix requiring an amendment to the building consent to address the non-compliant building work.

If a BCA issues such notices requiring an amendment to the building consent, the application for an amendment will be considered under section 112 as if a new building consent is being granted. Accordingly, under section 112, the authority must assess whether following the alterations the building as a whole will comply with the Building Code “as nearly as is reasonably practicable”. In this case this means that the performance of the intertenancy walls as a whole must comply “as nearly as reasonably possible” with the Building Code. Consideration was required of the penetrations and framing gaps exposed during the planned works, as well as in those areas not exposed.

Do the penetration and framing gaps comply with the Building Code as “nearly as is reasonably practicable”?

The approach for deciding if a building as a whole complies “as nearly as is reasonably practicable” with the Building Code involves the balancing of sacrifices and difficulties of upgrading, against the advantages of upgrading. The Determination concluded that it was reasonably practicable to remedy the penetration and framing gaps exposed during the planned works.

In regards to the penetration defects not exposed during the planned works; the Determination concluded that it was not reasonably practicable to remedy these. This view was based on the fact that the remedial work carried out during the alterations would have addressed the majority of the penetrations, given their location adjacent to the remediated exterior walls, and the significant costs in removing the linings in each unit to check those areas that had not been uncovered as part of the planned works.

With regards to the unexposed framing gaps, it was unclear how widespread, or significant an issue this was. Given the lack of information regarding the extent, severity and effect of this defect, and that there were no other building or fire safety features in place or proposed that would mitigate the reduction in fire separation performance, the Determination concluded that there was insufficient information to support the finding that the compliance “as nearly as is reasonable practicable” will be achieved. Additional information on this, along with a cost/benefit analysis, would be required in order for the Determination to reach a conclusion as to whether the building work would comply with 112(1)(a)(i).

The decision

In regards to compliance with section 112(1)(a)(i), the determination:

  • confirmed that the BCA correctly exercised its powers in respect of consideration of construction defects in both areas that were going to be exposed and those that would not be exposed during the planned works; and
  • concluded that it was not reasonably practicable to remedy the penetrations to the intertenancy walls in areas not exposed as part of the planned works; and
  • concluded there was insufficient information on which to make a determination about the compliance of the work to the extent required under section 112 with regard to framing gaps in the intertenancy walls that were not exposed as part of the consented alterations.

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