What to look out for when buying a house – Weather tightness

If you live in New Zealand and you have an interest in property in some way, shape, or form, you would have heard of leaky homes. Some houses built after the mid-1990s have not withstood New Zealand weather conditions and most likely do not comply with the current New Zealand Building Code.

We have compiled a list of common signs or risk areas for you to look out for in relation to leaky homes. Firstly take a look at the interior of the house. Below is a list of things to look out for when looking at a property.

  • Sagging of ceiling linings
  • Corrosion of fixings such as screws and nails
  • Uneven floor surfaces, like the lifting of vinyl
  • Moulg or fungi formation on surfaces (although this can also be due to poor ventilation)
  • Musty smells
  • Swollen materials such as skirting and architraves
  • Staining or discolouration of materials or surfaces
  • Stained or rotting carpet, or rusting of carpet fixings
  • Cracking in plaster

Next, take a look at the exterior of the building. Below is a list of things to look out for.

  • Type of cladding
  • Cladding fixing
  • Cladding detailing
  • Condition of cladding
  • Age
  • Windzone
  • Design
  • Roof type
  • Soffit depth

Examples of these are shown in the numbered diagram.

  1. Flat roofs, or roofs with parapets
  2. Roof to wall junctions
  3. Pergola fixings
  4. Handrail fixings
  5. Lack of flashings to windows and other penetrations
  6. Decks over living areas
  7. Balustrade to deck or balustrade to wall junctions
  8. Clearances at bottom of claggings/levels
  9. Levels of ground outside is above interior floor level

Predominant cladding types that have leaked in the past

  • Harditex
  • Polystrene (EIFS)
  • Solid Stucco


The government has established the Weathertight Homes Resolution Service (WHRS). Claims concerning leaky homes made to the WHRS must, as a general principle, be made within 10 years of the date of the act or omission that has caused the leak(s) (this timeframe has now passed).

By April 2010, the WHRS had received over 6,000 claims relating to over 7,700 residential properties. Industry experts believe this possibly represents only 15-20% of homes that have weather-tightness problems, with the balance being leaky homes that are yet to be identified, homes that have been identified but no action is being taken or those that are subject to some other form of resolution.

Proposed solution to the issue

The solutions include putting external plaster cladding systems on a cavity, following the basic philosophy for managing water known as the 4Ds – deflection, drainage, drying, and durability, as follows :

  1. Deflection – water is primarily deflected by the cladding.
  2. Drainage – water must be able to drain off roof and wall surfaces, and any water that penetrates the cladding must also be drained back out from within the cladding assembly.
  3. Drying – air needs to be able to circulate within wall assemblies to dry water absorbed by components, and wind and sun will dry water off the cladding exerior.
  4. Durability – all components of a cladding and wall assembly need to be appropriately durable for the relevant conditions and New Zealand Building Code durability requirements.

While you can inspect a property for defects on your own, we always recommend using an experienced building inspector. This reduces the risk of missing something or getting it wrong. Our experienced building inspectors are always available to help you, from the very top of the North Island to the very bottom of the South Island. Call us today to book your building inspection at 0800 422 388.