What is MDH?



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It is important to maintain the interior and exterior of any building, and medium-density housing is no exception.

Maintenance is also a requirement for ongoing Code compliance of the completed building. However, the maintenance needs of MDH can be more complex than for stand-alone homes. When this maintenance is not attended to, both building performance and occupants’ health may suffer.

Importance of maintenance

There are a number of factors that work to degrade or wear out building components. These include exposure to elements (rain, wind, low or high temperatures) as well as how it is used by occupants.

If a building is not maintained, it will not perform or be as durable as expected. Lack of maintenance may mean less-efficient operation of building systems and acceleration of deterioration where issues have not been addressed. For example, an air-conditioning system that is effectively serviced and maintained uses approximately 10% less energy than one that is poorly maintained.

Deferring MDH maintenance also has an accumulative cost, and estimates suggest that maintenance can cost 500% more than the original repair over a 20-year period. In addition, there is past evidence to suggest that MDH may not be as well built as other types of housing, further increasing the maintenance burden.

Like any building, poorly maintained MDH will lose value in the marketplace as deterioration spreads and accelerates, leading to greater overall maintenance costs than a well maintained building.

Durability requirements

New Zealand Building Code clause B2 Durability sets out the minimum durability requirements with normal maintenance. Like all buildings, MDH building elements must, with normal maintenance, continue to satisfy the performance requirements of the Building Code such as weathertightness and passive fire protection over the life of the building. The minimum time depends on the use of those building elements and the degree to which they can be accessed and their maintenance requirements detected.

Maintenance can be defined as regular or routine work to achieve the expected durability and performance of building elements or components of buildings. It may involve the replacement of components subject to wear or damage. It includes:

  • minor work such as repainting walls
  • major capital works such as replacing a roof or repainting the exterior
  • emergency major repairs such as earthquake strengthening
  • repairs of building defects such as responding to weathertightness issues or dealing with faulty passive fire protection.

Maintaining special MDH features

Medium-density construction usually includes features related to fire protection and noise reduction as well as shared walls, floors and common spaces. These features can make MDH more complex to maintain than traditional styles of home. As MDH is also often multi-storey, there are specific maintenance challenges related to height and access and unit ownership.

These challenges and the lack of a general Acceptable Solution for MDH mean that maintenance needs to be specifically designed to the requirements of each particular building.

Specified systems

Most MDH requires a compliance schedule and must pass an annual building warrant of fitness.

This is required if the MDH includes any of the following:

  1. Automatic fire suppression systems.
  2. Automatic or manual emergency warning systems for fire or other dangers. 
  3. Electromagnetic or automatic doors or windows.
  4. Emergency lighting systems.
  5. Escape route pressurisation systems.
  6. Riser mains for use by fire services.
  7. Automatic backflow preventers connected to a potable water supply.
  8. Lifts, escalators, travelators or other systems for moving people or goods.
  9. Mechanical ventilation or air-conditioning systems.
  10. Building maintenance units providing access to exterior and interior walls of buildings.
  11. Laboratory fume cupboards.
  12. Audio loops or other assistive listening systems.
  13. Smoke control systems.
  14. Emergency power systems or signs.
  15. Any or all of the following systems and features, provided they’re part of the means of escape from fire that also includes automatic fire suppression, riser mains, mechanical ventilation/air-conditioning or smoke-control (items 1–6, 9 and 13):
    • Systems for communicating spoken information intended to facilitate evacuation.
    • Final exits (as defined by clause A2 of the Building Code).
    • Fire separations,
    • Signs for communicating information intended to facilitate evacuation.
    • Smoke separations.

All buildings with a cable car, including single residential buildings, require a compliance schedule.

The building warrant of fitness needs to be renewed every 12 months. It will be issued following an inspection of the building to confirm it has been maintained as required in the building’s compliance schedule. This is issued at the completion of consented building work along with a Code Compliance Certificate.

See Specified systems for more information.

Joint responsibility

MDH maintenance is further complicated where there is joint ownership of the building. The Unit Titles Act 2010 provides a legal framework for the ownership and management of land and associated buildings and facilities.

It divides responsibility for maintaining MDH between:

  • the body corporate (maintains external systems)
  • each unit owner (maintains finishes and fitments within each dwelling).

Body corporate

The body corporate is the legal entity that represents all owners in a multi-unit property. It is comprised of all unit owners. The body corporate is responsible for:

  • maintaining the common property owned on behalf of the unit owners, including infrastructure and building elements
  • paying rates, setting levies, insurance and valuations and setting operational rules (beyond those in the Unit Titles Regulations 2011)
  • long-term maintenance planning to cover maintenance of common areas.

Infrastructure includes pipes, wires, ducts, conduits, gutters, watercourses, cables, channels, flues, gas, electricity, oil, shelter, fire protection, security, rubbish collection, air or any other services or utilities. Building elements include the structural integrity of the building, exterior aesthetics and the health and safety of those who occupy or use the building.

Body corporate levies may include an amount to cover the costs of repair and maintenance to common property or to building elements and infrastructure that serves more than one unit.

Often, a body corporate manager is contracted to perform some of the services of the body corporate on behalf of the unit owners. Companies that provide professional body corporate services typically offer services such as:

  • arranging maintenance of common property
  • organising facilities for meetings
  • administering the body corporate’s financial activities.


The Unit Titles Act requires that certain information is disclosed when a unit title is sold. This provides prospective owners with information about a unit, the development and the activities of the body corporate. The required disclosures include:

  • any unpaid costs relating to repairs to the unit
  • the body corporate levy
  • the details of proposed maintenance in the coming year
  • any claims under the Weathertight Homes Resolution Services Act 2006.

Maintenance planning

Maintenance is a continuous requirement throughout the life of the building. A maintenance plan can help ensure maintenance tasks are carried out in a timely manner and costs are not unexpected.

Plans for MDH maintenance usually reflect one or more of these approaches:

  • Condition-based – regular monitoring and inspection with maintenance carried out according to need.
  • Predictive – extensive diagnosis and monitoring with maintenance carried out as predicted.
  • Cyclical (time-based) – maintenance carried out as scheduled.
  • Response-based –maintenance carried out when an emergency or opportunity arises.

Long-term maintenance

While there is no requirement to develop a maintenance plan for each dwelling, the Unit Titles Act requires MDH developments to have a long-term plan for the maintenance of common areas. This is to identify future maintenance requirements, provide a basis for the levying of unit owners and provide ongoing guidance on maintenance decisions.

The plan must cover a period of at least 10 years and must describe:

  • the common property, building elements and infrastructure of the unit title development and any additional items the body corporate includes in the plan
  • the items the body corporate may opt not to maintain while the plan is in effect
  • the period covered by the plan
  • the age and remaining life of each item covered by the plan
  • the cost of maintaining and replacing each item covered by the plan
  • the long-term maintenance fund and the amount required to maintain it each year
  • the entity that prepared the plan.

The Unit Titles Act requires a body corporate to establish and maintain a long-term maintenance fund for expenditure relating to the long-term maintenance plan.

MBIE has published a template for use by bodies corporate to help ensure long-term maintenance plans include the correct information.

MDH maintenance challenges

MDH developments pose several unique challenges when it comes to maintenance.

Incentivising developers

The developer also has a major influence on future maintenance of MDH, as they set in place the parameters for the building design and the level of specification for materials and finishes. However, there are few incentives for developers to consider or limit the ongoing costs of maintenance or even to ensure maintenance is possible.

Developers bear all the costs and none of the benefits from designing and building low-maintenance or easily maintained housing. Further, it is not in the interests of the developer to clearly identify long-term maintenance requirements.

Informing owners

First-time purchasers of MDH are often unaware of their legal rights and obligations and those of the body corporate. While the Ministry of Business, Innovation and Employment and HOBANZ provide  information specifically for MDH owners, it is not always used by those who need it.

Within one development, the body corporate can comprise a massively diverse range of owners, all with different motivations and abilities to plan for and pay for maintenance. A concern is that purchasers of units may not be aware that they will be required to fund the replacement or repair of major components as a separate levy.

Quality of advice

Often, a body corporate will depend on independent advice from experts in the building industry, particularly relating to the maintenance requirements of common areas of the building. However, when an industry expert prepares a long-term maintenance plan for a body corporate, there is an incentive to overstate requirements so they will not be held liable for inadequate advice or future non-performance. This could result in owners paying more for maintenance than necessary. Sometimes, plans are prepared by people who do not have the appropriate qualifications or competencies.

Funding maintenance

Funding maintenance can be a challenge, especially when costs are high. When no contingency has been set aside in a long-term maintenance or replacement fund, major repairs can be difficult to fund. Since the late 1990s, repairs have been required due to earthquakes (as well as earthquake strengthening) and moisture problems (leaky homes).

Special levies, loans, insurances and legal action are options for bodies corporate when the long-term maintenance fund is insufficient to cover the cost of emergency repairs. However, owners may lack the ability to pay special levies, loans may be unavailable or at high cost, insurance companies may be unwilling to contribute and legal action is inherently uncertain.

Leaky homes

It is likely that some MDH developments built before 2008 are leaky buildings. The time limitation for bringing claims to the Weathertight Homes Resolution Service has now passed, and owners are precluded from obtaining funding from the government for repairs or accessing the dispute resolution services.

Earthquake strengthening

MDH that is 2 storeys high or more and comprises three or more dwellings must comply with the Building (Earthquake-prone Buildings) Amendment Act 2016. Notified owners of earthquake-prone buildings will need to obtain an engineering assessment and complete any remedial work within a specified timeframe.

Owners of multi-storey buildings, including MDH, must also comply with regional earthquake-strengthening requirements. A key requirement is that owners must secure unreinforced masonry parapets and façades on buildings in certain areas of Wellington City, Hutt City, Marlborough District and Hurunui District within specified timeframes.