Guidance for the building owner

Under the Building Act, homeowners must be given details of maintenance requirements when building work is complete. It can help to ensure that buildings continue to perform and that builders are less likely to be called back for faults or to be involved in weathertight repairs and disputes.

At the completion and handover of a new house, the building contractor must:

    • Provide a copy of any current insurance policy they hold for building work completed under the contract (but not policies that have expired).
    • Give copies of any guarantees/warranties for materials or services used in the work. This should include how to make a claim, whether or not the guarantee/warranty is transferable, and whether it must be signed and returned to the company that issued it.
    • Explain about what maintenance work must be done, especially if this is required to meet Building Code or guarantee/warranty requirements.

    This information must be given to clients regardless of the price of the work.

      The designer should also provide the homeowner with a current set of as-built documents and a summary of all the components incorporated into the exterior envelope.

      It is also a good idea for designers and builders to provide a seasonal maintenance guide and log that will make it easy for homeowners to plan future maintenance. This should cover all the fundamentals of exterior maintenance requirements, such as:

      • clearing roof gutters
      • inspecting roof flashings/membranes/claddings
      • cleaning and recoating roof finishes
      • cleaning and recoating wall finishes
      • inspecting window and door flashings and glass seals
      • inspecting and replacing sealants
      • keeping base ventilation clear.

      The provision of a maintenance guide often results in the homeowner taking better care of their home and being aware of issues that may occur that are beyond the control of the builder. This can also result in fewer call backs for the builder. BRANZ has a maintenance schedule tool that can help.

      BRANZ also has a useful website Maintaining my Home.

      Identifying potential issues

      Designers and builders can also make homeowners aware of how to inspect the building exterior to identify any potential problems that may come about as the building ages. This can help to ensure that preventative work is carried out to avoid a future failure occurring, thereby saving a lot of time, effort and expense and avoiding potential issues of liability.

      This is particularly important for very high risk buildings such as those that are very complex, have monolithic face sealed exteriors, parapets, balustrades and minimal eaves protection or are built in very exposed locations.

      In particular, designers and builders should make the homeowner aware that weathertightness problems may result from:

      • cracks, splits or open joints in the cladding
      • sealant that has come loose
      • metal corrosion
      • raised flashings
      • gaps at the ends of flashings
      • rotten timber
      • cupped or buckled weatherboards
      • loose-fitting cover boards, scribers or plugs
      • missing roof fixings or holes in the roof
      • overflowing spouting
      • surface efflorescence
      • faded or peeled coatings
      • stained or dark patches on walls
      • gaps in junctions between different materials or building features
      • gaps around cantilevered deck joists or other cladding penetrations
      • gaps around window seals or sashes
      • joints or mitres that have opened up or where the paint has cracked
      • water ponding on a roof or membrane deck surface.

      Owners should also be made aware of the things that may occur inside a building that may be indicators of weathertightness failure, such as:

      • stained, mouldy or damp plasterboard on walls or ceilings
      • bubbles forming on paint finishes
      • peeling wallpaper
      • gaps appearing between the skirting and the wall
      • swollen skirting timber and window or door reveals
      • stained, damp or rotten carpet
      • swollen MDF furniture.

      Patchy or isolated changes in the colour of the exterior paint or cracking in exterior finishes may also be indicators of weathertightness failures.

      Owners should be made aware that leaks can be difficult to identity but will tend to worsen over time. If any of the above risk factors seem to be present, owners should evaluate the weathertightness of their home more fully. This may involve:

      • a thorough survey by an NZIBS Building Surveyor
      • a report of the findings, including an evaluation of the risk of future failures
      • estimates of the cost of various repair options.

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      Critical maintenance

      Designers and builders also need to ensure that homeowners are aware of any critical aspects of the exterior cladding that need to be maintained and of the potential for weathertightness failure if these are not maintained:

      • Face seal coatings must be regularly cleaned and recoated – many cladding materials that incorporate face seal coatings are fundamentally reliant upon these for weathertight performance, and if they are not maintained, the cladding material will absorb water and fail.
      • Critical sealant joints – many cladding systems incorporate exposed sealant joints that are fundamental in stopping water penetrating critical junctions in the exterior.
      • Critical flashings, such as window head flashings, which ensure that water is deflected over a critical penetration in the cladding.

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      Minimising maintenance requirements

      Designers can minimise maintenance requirements by selecting materials and finishes that are more durable, with a weathertight performance that is less reliant upon regular maintenance.

      The quality of materials and finishes will have an impact on their durability and maintenance requirements and so will environmental factors such as wind, rain, humidity, air pollution, temperature fluctuations and proximity to the coast or geothermal areas.

      If the builder feels that there may be an issue with the long-term performance of any specified system, the designer should be informed.

Updated: 21 June 2019