More than half of Wellington homes on the market are considered "dangerously damp" and one in eight need major repairs, according to a Victoria University study.
A sample of 12 years of data from building inspections on stand-alone houses by Buildsure Associates was combed through as part of the research.
Study co-author and senior lecturer at the School of Architecture Dr Nigel Isaacs says the findings were disturbing.
"What is worrying is that houses are in general a person's most expensive asset, yet at best only one in five houses for sale is showing up in good repair," Dr Isaacs says.
"One in eight of the houses was considered to have major maintenance problems that exceed general wear and tear."
Among the 10 most common problems were asbestos, concrete spalling, corrosion, timber decay, electrics, external water management, movement, subfloor moisture, subfloor structure and wall moisture.
Of those properties studied, 36 percent were likely to have asbestos in the roof or wall cladding, 35 percent had high water moisture levels, and 53 percent had insufficient subfloor ventilation which could lead to decay or corrosion.
"Many of these may have potential health and safety implications for the house owners or occupiers," Dr Isaacs says.
But Dr Isaacs says these aren't isolated problems, but are seen across the country in stand-alone timber houses.
"Half the houses analysed had dangerously high moisture loads in a number of places. A lot of the issues relate to water being in the wrong place or the houses being poorly designed or constructed," Dr Isaacs says.
Data for the collaborative study was taken from a random sample of 70 inspection reports and collated by students.
The research was published in Case Studies of Building Pathology in Cultural Heritage.