Branz said newest houses seemed to be the biggest offenders.
New Zealand houses are often built in such a way they will end up damp, and most homeowners know they need to fix up their houses but usually do not, a building research study has found.
Of the 565 owner-occupied houses inspected by researchers from the Building Research Association of
New Zealand (Branz), each house needed an average of $3700 worth of repairs.
When interviewed, homeowners said they spent an average of less than $1300 a year home maintenance, which researchers said was not enough to maintain the houses.
This was, however, an improvement on previous years.
In 1999, houses needed about $4900 worth of serious repairs, and researchers said the average overall condition of houses was better than in previous surveys.
The survey found in 58 per cent of the houses, the water cylinder had no earthquake restraints.
Dampness was a major problem - caused by poor ventilation, and improper cladding, and 43 per cent had poor or seriously inadequate underfloor ventilation.
This was a major problem, which could lead to timber decay, invasion by fungus and borer and dampness, Branz materials manager Mark Jones wrote in the October edition of the association's magazine, Build.
"Around 40 litres of water evaporates from the soil under an average house every day.
"In a number of houses inspected in the survey, water was flowing under the house from driveways, paths and lawns," he said.
Many houses also had poor kitchen and bathroom ventilation, and cladding used on the outside of houses on almost half the houses was too close to the ground.
"Increasingly, priority seems to be given to linking inside and outside at the expense of good building practice, and the newest houses seem to be the biggest offenders," Mr Jones said.
Also, 78 per cent of the deck barriers on houses - and most houses had decks - did not comply with building requirements, being too low, or having gaps that were too big.
- NZPA
