Material Use

Maintenance and sustainability are closely linked. When appropriate maintenance is carried out on a property the building materials last longer and fewer expensive repairs, if any, are required.

There are specific obligations regarding maintenance of buildings and building materials:

• It is a requirement that buildings continue to meet New Zealand Building Code requirements for the duration of their intended life.
• E2/AS1 requires that: “Maintenance shall be carried out as necessary to achieve the required durability of materials, components and junctions.” The Acceptable Solution describes specific maintenance requirements such as washing exterior surfaces, maintaining finish coatings and maintaining certain minimum clearances.
• The consumer protection measures in the Building Act include the requirement that, (amongst other things) when a job is completed the contractor gives the clients information about the maintenance they must do (materials and processes), especially if maintenance is necessary to meet Building Code, guarantee or warranty requirements.

Wall cladding and coating systems, in particular, are likely to need regular maintenance to remain waterproof and durable. Some cladding systems also incorporate functional components (such as drained and vented cavity drainage outlets) that require maintenance and, in some cases, protection to ensure that they continue to function.

BRANZ House Condition Surveys, conducted approximately every 5 years from 1994 to 2015/16, assessed the standard of maintenance in New Zealand houses. The 2015/16 survey found that:

• 48% of owner-occupied homes were well maintained, 38% were reasonably maintained and 14% were poorly maintained
• 24% of rental houses were well maintained, 44% reasonably maintained and 32% poorly maintained.

Maintenance is best done in a structured, organised way using a maintenance schedule. A maintenance schedule is a document that describes the materials or building elements in a property and the maintenance that they require. Frequency of tasks is typically described: washing down painted weatherboard cladding at least six-monthly, for example, and repainting every 8–10 years. A maintenance schedule can:

• help property owners know what they should do to keep the property in good condition
• give builders and property owners the details of a building material years after the property was built
• reduce a builder’s potential liability if lack of maintenance leads to issues such as weathertightness problems.

BRANZ provides a considerable number of resources around maintenance, from Build articles to sections in books, bulletins and the website www.maintainingmyhome.org.nz. 

^{Updated: 12 July 2022}