Determinations issued
Determination 2007/67
Retaining wall at Beach Road, Waihi Beach, Western Bay of Plenty
The matter for determination
The matter for determination was the refusal by a building consent authority to issue a code compliance certificate for a boundary retaining wall. The retaining wall had been built in connection with the removal of an existing house and its replacement by a new house according to a building consent issued by the authority. The building consent was subsequently amended to include the strengthening of the retaining wall as it had been built. However, that amendment had been based on a certificate issued by the owner's consulting engineer, and that certificate was withdrawn in the course of the determination when the engineer realised it had been based on certain mistaken assumptions.
In the course of the determination, an independent site report was obtained on the retaining wall and independent calculations based on an assessment of the site soil properties.
The retaining wall
As shown in the figures below and overleaf taken from the determination, the retaining wall was of timber pole-and-batten construction, extended at the top to form a boundary fence. The retaining wall as a whole was of varying height and retained a depth of between about 1.1 m and about 2.4 m. It was constructed in two stages, the lower part first by one contractor and the upper part later by another contractor. The upper part was immediately behind the top of the lower part.
Figure 1: Ground profile along the retaining wall showing height of soil retained.
Figure 2: Typical cross-section of the retaining wall (taken from the expert’s report).
The owner raised a number of questions, including the following.
Question 1:
Was the retaining wall entitled to a code compliance certificate because it complied with the original building consent?
Answer:
The original building consent showed the location of the retaining wall but gave no details of its construction. The determination found that the original building consent did not cover the retaining wall because such walls can be constructed of many different materials, and in so many different ways, that it was unacceptable to claim that a building consent had been issued for a retaining wall without any details as to its 'design, height, etc' having been included in the plans and specifications1. As the retaining wall did not comply with the building consent, it was not entitled to a code compliance certificate.
Question 2:
Was a building consent required for the retaining wall?
Under Schedule 1(c) of the Building Act 2004, a building consent is not required for a retaining wall that retains not more than 1.5 m depth of ground and that does not support any surcharge.
A surcharge is any feature, such as sloping ground, or a road, or another building, which is in addition to the load imposed by the retained soil. Accordingly, it is acceptable for a cut to be retained by a series of 1.5 m retaining walls above each other provided that no higher wall imposes a surcharge on a lower wall. There must therefore be a certain horizontal distance between the walls, depending on the particular soil properties of the site. In this case, the horizontal distance was minimal, so that the upper wall imposed a load ('surcharge') on the lower wall.
Answer:
It was determined that Schedule 1(c) did not exempt the retaining wall from the need for a building consent because the retaining wall had to be considered as a single structure in which the lower and upper parts acted together to retain the full height of the cut. The lower and upper parts could not be regarded as separate and independent structures because the upper part depended on the lower part for support and stability. Even if the upper part considered on its own had come within Schedule 1(c), under section 17 it would still have to comply with the Building Code.
Question 3:
Did the retaining wall comply with the Building Code?
Answer:
The independent site report showed that the retaining wall was showing signs of incipient failure, and the independent calculations indicated the retaining wall had only a fraction of the structural capacity required to comply with Clause B1. The retaining wall, as built, did not comply with the Building Code.
Decision
The determination:
- reversed the building consent authority's decision to amend the building consent
- determined the retaining wall, as built, did not comply with the Building Code
- confirmed the building consent authority's decision to refuse to issue a code compliance certificate for the retaining wall.
Determination 2007/70
Facilities for people with disabilities in the self-care areas of Spring Hill Prison, Te Kauwhata
The building work
The Spring Hill Prison complex of buildings was at a late stage of construction under a three-stage building consent. The complex included several self-care residential buildings ('the units') to house pre-release prisoners who had graduated from more secure accommodation.It was not disputed the entire prison complex came within Schedule 2(g) of the Building Act 2004. Under section 118, the units were required to have features to allow use by people with disabilities (to be 'accessible').
The matter for determination
There was wheelchair access to and within each unit, but the Department of Corrections ('the owner') had not intended to fit out any of the units with accessible toilet, kitchen, and laundry facilities until such facilities were actually needed for a wheelchair user. However, the building consent authority refused to issue a code compliance certificate unless the fit-out of the units included accessible facilities.
The owner applied for a determination on the authority's decision, saying the matter for determination was the need to fit out a certain number of the units according to Clause 14 Accessible Accommodation of NZS 4121: 2001 Design for Access and Mobility - Buildings and Associated Facilities.
Discussion
There was no dispute about what accessible provisions are required, only about whether they had to be provided when the units were constructed, or later when those provisions were actually needed, because a wheelchair user was to be housed in a self-care area.Following the precedent of several previous determinations, it was considered the owner's assurance of 'management assistance and/or fittings being altered to suit the particular individual's needs' did not amount to reasonable grounds on which the building consent authority could be satisfied the units complied with Building Code accessibility provisions.
There could be no question of a waiver or modification of the Building Code because, under sections 67 and 69 of the Building Act, neither the building consent authority nor the Chief Executive of the Department of Building and Housing had the power to grant waivers or modifications of the accessibility provisions for a new building. Therefore, the prison complex had to comply with those provisions.
Decision
The determination:
- determined that the owner's proposed fit-out of the units did not comply with the accessibility requirements of Building Code Clauses G1 and G3.
- Confirmed the building consent authority's decision to refuse to issue a code compliance certificate for the complex unless a certain number of the units were fitted out with accessible toilet and kitchen facilities.
1 Comment: In Determination 2007/53 it was accepted that a building consent covered plumbing despite the fact that no details of the plumbing were shown in the plans and specifications. The difference in approach reflects the fact that plumbing is usually installed according to generally-accepted practice whereas retaining walls involve structural considerations depending on site soil properties. This means all but the smallest retaining walls need to be individually designed.
To read all the determinations in summary or in full, go to: www.dbh.govt.nz/determinations