Watch: How an Auckland duplex was built in four days

This house was built in just after a day, after the duplex trial in April.

A time lapse video shows how Fletcher Living built a new Auckland residential duplex worth nearly $2 million in four days.

Yesterday the company said it had built a single Auckland house in a day.

"This was the speed test," a Fletcher Living spokeswoman said of the duplex home construction, built during April just before Easter. The 177sq m four-bedroom homes at Hobsonville Point sold for $935,000 each.

Fletcher's Steve Evans said Auckland houses usually take six to nine months to build. One day was Fletcher Living's aim but building such a substantial duplex in four days was a significant achievement, he said.

Techniques used on the duplex were then applied and honed for the house built this week, he said.

Evans said in just four days, the duplex was weathertight and ready for interior and exterior finishing. Six weeks later it was completed and signed off by Auckland Council ready for sale.

"With the first duplex home, we proved to ourselves it could be done, and with this second home we have been speed testing to see just how fast we can do it. We have identified a number of changes we can make in order to build even faster - to one duplex every two days," Evans said.

"We're now looking at how we can best mass produce these homes and begin building them in large numbers," he said.

Pamela Bell, chief executive of industry group PrefabNZ, said the house-in-a-day announcement yesterday had caused considerable interest in her sector.

The video is titled "off site manufactured house trial" and is part of Fletcher's group innovation drive. It shows the duplex floor slab was already down before the clock started counting down the four days.

On day one, a crawler crane is at work on the first duplex, swinging panelised wall and floor components on to the site.

Day two sees most of the first home up.

By day three, the pitched roof is on, with windows and doors already installed before components are brought to the site. Work has also then begun on the second duplex.

Day four shows panelised floor and wall components craned onto the second site, the roof going on.

The video then shows close-up images: the floor pad pour, scaffolding being erected and the panelised walls being made in the former Laminex factory at Papakura. Windows are installed in walls before the panels are trucked to the site and craned into place.

Those closer-up shots show a doll house-like construction techniques, with walls of a second-level home placed on top of the floor. A drone is used to show the house in relation to the street.

The pitched roof is brought in, fully clad, swung through the air but secured with giant 400kg hooks on the roof edge before it goes into place.