Earthworks are under way for a new 42-section subdivision of "high performance" homes in Whanganui's popular Otamatea area on the edge of St John's Hill.
The subdivision will have views across the city and out to the Tasman Sea, a similar aspect to the nearby subdivision reached from Tirimoana Place.
The business involved is Sustainabuilt Developments Ltd, which bought just over 4ha of land there two years ago, co-director Baden Brown said. The land is sandy, gently sloping and will be reached from a new intersection on State Highway 3.
Sustainabuilt was formed in May 2016, as a vehicle to combine the interests of Brown as one of the founders of the eHaus brand of energy-efficient houses, and of Simon Penn, the licensed eHaus builder for this region.
Simon Penn Building's team of 12 carpenters and five office staff will construct all the houses at the new subdivision.
It will build about 12 a year over four or five years. That will probably start around the end of 2022, once Loader I D Ltd has finished the site works.
The houses are expected to be more energy-efficient than those built to the current code, Brown said.
It's not a requirement of the subdivision, but it's what most of the buyers want.
Tasman Estate may be one of just a few New Zealand subdivisions built with sustainability in mind.
Ten sections have been sold already, and 19 others are under contract.
"The interest has been phenomenal. It's a reflection that land is scarce and Whanganui is having a small resurgence, and I also think the site itself is particularly attractive to people.
"It's in Otamatea, not a name recognised by iwi, but it's a fairly popular area, with sea views, a rolling site, and it's quite a fair way from the main road with no traffic noise," Brown said.
Buyers purchase a house and land package and decide on their house design. There are standard eHaus designs but individual differences are expected.
One requirement is that all the houses have to be one-storey, with a height limit of 5.2m, to ensure they all get sunshine.
"To make a home function properly you need sunlight," Brown said.
The eHaus designs are built to be warm in winter, with minimal energy used in heating, and cool in summer.
"We model it to make sure that the homes are doing both."
Stormwater from Tasman Estate will run down the slope to land Whanganui District Council has purchased to hold it.
The land to be built on has "huge cultural value" to local iwi, Brown said.
Before developing it Sustainabuilt needed an archaeological authority from Heritage New Zealand and two archaeological investigations.
Archaeologist Kevin Jones has been on site in case pre-1900 remains are found during topsoil removal, and kaitiaki cultural monitors from Te Rūnanga o Tūpoho's combined hapū are also present.
The development plan was decided with the hapū, and they have been asked to contribute street names. Earthwork has already turned up hāngi stones and shell midden.
Anything significant that is found will be left in place until it can be investigated by an archaeologist, and there will probably be some kind of permanent monument or memorial to the former inhabitants.
Sustainabuilt has a good relationship with the iwi, Brown said, and there had been many hui in the "very involved" process.
He's glad work is finally under way because Sustainabuilt's first subdivision planned for 20 sections in London St had to be canned when the soil was found to have high arsenic levels.
Some of those who have bought sections at Tasman Estate have been waiting two years, and Brown is grateful for their patience.
"We are pleased to finally get to this stage," he said.