What is MDH?



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The New Zealand Building Code is the primary driver of the building consent process.

It prescribes functional requirements and performance criteria that buildings, including MDH, must achieve in relation to their intended use.

Nationally, building consents for MDH developments have risen considerably since 2011. In December 2016, Statistics New Zealand published data for MDH building consents over the previous 12-month period. It shows:

  • 0% increase in townhouses, flats and units
  • 8% increase in retirement village units
  • 1% decrease in apartments.

Performance requirements

Compliance with the performance requirements of the Building Code can be achieved in one of three ways:

  • Acceptable Solution – a prescriptive design methodology that, if followed, will result in a design that meets the performance requirements of the Building Code. A difficulty is that a number of the Acceptable Solutions such as E2/AS1 are not applicable to buildings taller than 10 m.
  • Verification Method – a suite of tests or calculations that a design must pass or satisfy in order to meet the performance requirements of the Building Code.
  • Alternative Solution – requires a designer to prove that their alternative method meets the performance requirements of the Building Code. (Once accepted by the building consent authority and consented, it becomes an Alternative Solution.)

A building consent must be issued by a building consent authority (BCA) where the design and detailing follows a deemed-to-comply solution or where a BCA is satisfied that the proposed construction will be Code-compliant.

Granting of a building consent confirms that an MDH development, if built according to the information provided in the consent application, will comply with the performance requirements of the Building Code. If a building is constructed in accordance with the consented documents, a BCA must issue a Code Compliance Certificate.

A BCA must process building consent applications within 20 working days. It can, however, request further information where insufficient information is considered to have been supplied. This pauses the process until the BCA receives the relevant information from the developer.

Restricted building work

Restricted building work is design and building work that is crucial to the integrity of the building, such as the primary structure, external moisture management and fire design.

Restricted building work that applies to houses and small-to-medium apartment buildings can only be carried out or supervised by a licensed building practitioner. Restricted building work therefore applies to any building that:

  • contains two or more residential units (apartments) or residential facilities (foyer, laundry, garage and so on)
  • does not contain commercial units or facilities
  • has a maximum height of 10 m (typically 3 storeys).

Building consent processes for MDH can create challenges for councils and developers because of uncertainty around design requirements and the way the consent process is implemented.

Many believe that Code-related challenges stem from the fact that Acceptable Solutions were not necessarily designed with the current range of MDH in mind.

The issues mostly relate to the Acceptable Solutions to these clauses:

  • C Protection from fire – Acceptable Solutions C1–C7 are considered overly complex, confusing and expensive to comply with.
  • E2 External moisture – E2/AS1 does not apply to mid-rise MDH buildings over 10 m.
  • G6 Airborne and impact sound – G4/AS1 is considered out of date and does not go far enough to protect consumers.

Lack of clarity about how to apply Acceptable Solutions and Verification Methods often leads architects and designers towards alternative methods.

Any alternative method must be supported by documentation (to support the compliance of the proposed solution) following one of the defined compliance paths such as expert opinion. This can be a costly exercise, and councils are often unwilling to approve applications for consent due to uncertainty about the potential risks.

In its 2012 housing affordability report, the Productivity Commission identified a number of problems with the building regulatory framework. Several relate to the MDH building consent process, including:

  • slow and uncertain building regulations and inspection services
  • no clear pathway for Alternative Solutions to become Acceptable Solutions
  • difficulty in retaining sufficient capability within BCAs
  • poorly applied charges for infrastructure.

BRANZ studies indicate that some of these issues continue to hamper the development of MDH in New Zealand.

Incomplete applications

BCAs must process an application for a building consent within 20 working days of it being lodged. However, under section 92 of the RMA, they can write to the consent applicant and formally issue a request for further information (RFI). This effectively ‘stops the clock’ until sufficient information is received.

These provisions allow councils to meet performance and accreditation requirements, because they can still show that they made a decision on most applications within the 20-working day time limit. However, it means that while the total time spent processing the application may be within the 20-day limit, the actual elapsed time may be much longer.

This formal process may not be as effective as having further face-to-face meetings to clarify specific requirements. In particular, pre-application meetings are known to be a useful tool to improve engagement and reduce the number of RFIs issued by councils.