Major Maintenance Matters


One of the main problems with New Zealand homes is the amount of moisture that collects and stays inside. Damp homes are unhealthy and harder to heat.

You can combat persistent damp in your home by:

  • insulating (under the floor, in the ceiling and walls)
  • ventilating (including extractor fans in bathrooms and kitchens, open windows, using a dehumidifier or forced ventilation system, keeping vents clear)
  • heating (aim to keep the indoor temperature at a minimum of 16 degrees)
  • replacing unflued gas heaters with electric or flued gas heaters.


Leaking pipes or condensation can cause excessive moisture. You should treat the cause of excessive moisture at the same time as addressing its effects. Excessive moisture can also indicate that your home is a leaky building, which could require extensive repairs.

Mould, water stains and musty smells in houses built or renovated since the early 1990s can be the first signs of a leaky or non-weathertight house. They need to be thoroughly investigated. Owners who think their homes could have weathertightness problems because of their design and construction methods should seek early expert advice.

It is important that leaky homes are repaired promptly and properly to stop further damage. Good quality early repairs mean homeowners avoid additional costs for repairing further damage. Owners of tenanted houses likely to have weathertightness issues should regularly check their properties and ask their tenants to report early signs of problems.

Fibre-cement claddings

Modern homes with monolithic fibre-cement claddings are often sold as ‘low maintenance’ homes, but most of these speciality exteriors need more maintenance than a weatherboard house. Check with the cladding manufacturer, as you may be required to wash the cladding at specific intervals to keep the warranty valid. Always follow the manufacturer’s recommendations.

It is particularly important to wash the cladding if your house is near the sea and where wall areas are sheltered from regular rain washing. It is important to use a soft brush and low-pressure hose to wash the cladding – do not use a water blaster as they can damage claddings and force water through gaps and joints.

If your home was built after the early 1990s and has any risk of being a leaky building, you need to be especially vigilant in your maintenance checks. Carry out a careful inspection of the cladding at least once a year.

The main things to look for are:

  • places where water can get into the framing
  • signs that water has already got in.


Water might get in:

  • through holes
  • through cracks
  • through loose cladding
  • through holes around fixings (like aerials)
  • through joints that have separated
  • around doors and windows
  • anywhere the sealing has failed
  • anywhere water can pool against the cladding.


Look for signs that moisture might be soaking into the cladding, often indicated by darker colouration along the bottom edges of the cladding.

Pay attention to vulnerable areas by:

  • checking around the house to make sure the cladding is at least 175mm above the lawn or garden, or 100mm above paved surfaces
  • checking pergolas, cantilevered decks, poorly formed flashings (waterproofing strips) that do not protect doors and windows, and meter boxes which are not sealed or flashed
  • checking any areas where bolts, screws or handrails penetrate the cladding.


Brick houses

Most brick houses are brick veneer, with a cavity between the timber framing and the brickwork. You need to keep the drainage cavities at the base of the walls clear – check regularly that soil and plants are not blocking them.

Never let insulation material fill the cavity behind the brick veneer as this will seriously alter the weatherproofing performance of the cladding.

Concrete block houses

Most solid concrete block homes are constructed of reinforced masonry. They rely on the externally applied waterproof coating for weathertightness and this must be maintained to keep water out.

Balconies and decks

Common on apartments and many modern homes, enclosed decks and balconies require good design and regular maintenance to ensure adequate drainage. They should be built with a slope to allow water to run off to a collection point such as a downpipe. Keep drainage outlets clear of leaves and other items that might block them.

Balconies enclosed with solid walls often suffer weathertightness problems and need to be frequently checked for signs of rotting, swelling, cracks and rust around bolts and flashings.


Once a year you should check your roof cladding, chimneys and flashings (waterproofing strips that protect vulnerable areas) to ensure problems are not developing.

Things to look for include flashings that have corroded or lifted and crumbling chimney mortar. Overhanging branches can damage roofing materials, so it’s important to keep trees next to your house well-trimmed.

Check with the manufacturer of your roofing material to find out about any special maintenance requirements. For example, paint-on membranes must be re-coated every 7-10 years.

Drains and gutters

Blocked and damaged drains can cause serious flooding so it’s important to contact a professional drain cleaner as soon as you become aware of any problems. Tree roots can cause clay (earthenware) drainage pipes to crack, so take care where you plant trees with extensive root systems. Guttering and spouting need to be cleaned out at least once a year as leaves can easily collect and block them.