Determinations issued
Determination 2006/54
Safety barrier to a house deck
The matter for determination
The application for determination arose from the refusal of a territorial authority to issue a code compliance certificate for a safety barrier to a house deck ('the barrier'). Because the building consent had been issued before the Building Act 2004 ('the current Act') came into force, the matter had to be determined under the former Building Act 1991 ('the former Act').
Under the former Act, a territorial authority could refuse to issue a code compliance certificate on the grounds that the building work concerned did not comply with the Building Code, whether or not it complied with the building consent. That has now changed, and under the current Act a territorial authority must issue a code compliance certificate if the work complies with the building consent.
The barrier
The barrier was an alternative solution that had been designed by an architect and built in accordance with a building consent issued by the territorial authority. A building certifier had issued a certificate for the work, which the territorial authority had relied on when issuing the consent. By the time construction was completed, the certifier had gone out of business and its responsibilities devolved to the territorial authority.
Discussion
For safety barriers in places likely to be frequented by young children, including houses, the F4/AS1 Acceptable Solution is a barrier 1000 mm high with no openings that will permit the passage of a 100 mm sphere and no toeholds between the heights of 150 mm and 760 mm above floor level. That Acceptable Solution restricts the passage of children under 6 and is high enough to prevent adults falling over it.
The barrier did comply with the F4/AS1 Acceptable Solution for a low but wide barrier in front of fixed seating (as in a theatre), but the Chief Executive considered the solution could not be applied to a house deck.
The barrier also complied with the US standard NBS IR 76 1131, which had been accepted as an alternative solution in Determination 2002/4. However, that determination related to the risk of people falling over a barrier not to children climbing it, so the Chief Executive considered it was not relevant.
Using the 1000 mm high 'restricted openings and toe-holds' Acceptable Solution as a guideline or benchmark, factors to be taken into account as possibly compensating for the lesser height of the barrier were the internal overhang of the top of the barrier together with its rounded edge.
Tests1 had established that the Acceptable Solution is 100 percent effective for children under 3, but the barrier could be climbed by many 3-year-olds and by most 4-year-olds. It was legitimate to conclude that the Acceptable Solution would prevent children under 3 from climbing over it and would restrict but not prevent older children from climbing over it.
In this case, it was accepted that the barrier would prevent children under 3 from climbing over it. However, the question was whether it would be at least as difficult for children aged 4 and 5 to climb the barrier as it was for them to climb the corresponding F4/AS1 barrier.
The Chief Executive concluded that the barrier would not be as difficult to climb as a barrier built to the Acceptable Solution. In coming to that conclusion, the Chief Executive recognised that, with the barrier being 760 mm wide with open vision areas of 50 mm, children could see how high above the ground this was. If they were to climb on top, they would be on 760 mm wide planking and might realise they had made a mistake. However, the Chief Executive was not convinced that children in the 3 to 6 age group, when faced with the challenge of climbing the barrier, could be relied on to make such rational judgements.
Decision
The Chief Executive determined that the barrier would not be as difficult for a child to climb as a barrier built to the corresponding Acceptable Solution, and therefore it did not comply with Clause F4 of the Building Code. Accordingly, the Chief Executive confirmed the territorial authority's decision to refuse to issue the code compliance certificate.
Determination 2006/55
Refusal to approve the installation of aluminium-faced panel cladding
The matter for determination
The application arose from a dispute about whether the installation of aluminium cladding for a partly constructed house complied with Clauses B2 Durability and E2 External Moisture of the Building Code.
The territorial authority declined approval of the cladding installation because it was not satisfied that the design complied with Clauses B2 and E2. During the construction of the house, the territorial authority informed the applicant that amended plans and junction details must be provided for the aluminium-faced panel cladding, as the aluminium panels needed to be fixed over a 20 mm drained and vented cavity.
The owner, acting through an agent, applied for the determination.
The building and cladding
The building is a two-storey detached house that is partially complete. The wall cladding, which is applied to three elevations of the building, is an 'Alpolic' system comprising 416 mm high aluminium-faced composite panels. The fixing system provides a continuous drained cavity that is about 25mm at the body of the panel and about 5 mm at the edge joins. Drainage holes are provided at the horizontal return at the bottom of the cladding.
The initial submission
The applicant submitted that the cladding has a fixing system that provides a 20 mm cavity and battens were not therefore required.
The draft determination
The Chief Executive sent the parties a draft determination, which was accepted by the applicant.
The territorial authority responded to a draft, noting that there were a number of areas where the panel system as installed on the house differed from the manufacturer's installation details.
The Department commissioned an independent expert ('the expert') to inspect the panelling to clarify the general dimensions of the system. The expert inspected the system and submitted a report, which the Department considered. The draft determination was subsequently amended.
The final determination
The final determination discussed the evaluation framework within which the compliance of the cladding system was to be assessed, as well as the weather-tightness risks and performance associated with such a system.
The Chief Executive was of the opinion that, while the proposed cladding system must be considered to be an alternative solution, it was useful to make some comparisons with the Acceptable Solution E2/AS1.It was noted that E2/AS1 makes clear that 'there are circumstances where the combination of risk factors applying to a particular building, or part of a building, on a particular site, may mean that the building will perform satisfactorily, and therefore be code compliant, without a drained and ventilated wall cavity'.
The Chief Executive did not accept that the drainage and drying provided by the cladding is equivalent to that provided by a 20 mm drained cavity as specified in E2/AS1. However, as the panel edges of the cladding at joint positions are limited to the thickness of the panel material, the relevant characteristics of this cladding could be compared to those of vertical profiled metal cladding specified in E2/AS1.
Comparing the features of the E2/AS1 cladding with that of the cladding in question, it was considered that the weathertightness performance of the latter is likely to be at least equivalent to that of the former.
If the proposed aluminium-faced panel cladding system is installed as designed, the cladding system can reasonably be expected to be compliant with Clause E2, and, if properly maintained, Clause B2.
The Chief Executive noted certain compensating factors relating to the building and its cladding that may help the performance of the cladding and help compensate for the lack of constant depth in the drained cavity.
It was also noted that further compensating factors should be provided to help the performance of the proposed cladding in this particular case. These being:
- 'thorough documentation, to be submitted to the territorial authority for approval, which shows how the junctions and penetrations for the proposed cladding are to be constructed'
- 'thorough inspections during the installation of the wall cladding to ensure that junctions and penetrations are constructed in accordance with those approved details'.
The decision
The Chief Executive determined that there were reasonable grounds to suppose that the proposed cladding system, if carefully completed in accordance with the manufacturer's instructions, and if subject to careful maintenance, will comply with the requirements of Clauses B2 and E2 of the Building Code.
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