Building a 3D printed house 'like piping on a cake'

RNZ NEWS | Natalie Akoorie | 30 Jan 2025

The country's first 3D printed show home opens in Hamilton today and so far it's attracting a lot of interest.

Curved concrete walls with a distinctive rope-like texture are the first clue the show home in Rotokauri is no ordinary house.

That's because all the walls have been made using a 3D printer, nicknamed Horace, at the Qorox Printing Facility on the southern outskirts of Hamilton.

Iconic Construction director Nick Lane likened the printing process to cake decorating.

"Basically, the printer arm just moves round and round and round. It's almost like piping on a cake - building up layer by layer.

"And it's running at about half a metre a second when we're printing. The material that we're using ... it's got an initial set time of about three minutes. For concrete that's pretty quick."

Lane said Horace printed the walls for the three-bedroom, two-bathroom show home in 24 hours over a two-week period, using an architect's design.

"The boys here will then take the (architect's) file and turn it into a 3D printing file which basically looks at the whole entire wall and slices it up into each individual layer.

"So it's essentially just a gigantic dot-to-dot drawer."

Construction of the show home began in July after a few consenting issues due to the uniqueness of the project.

But Lane said the 3D printer would eventually cut down a standard build time to as little as three months.

Iconic Construction general manager Johnny Gordon said the technology provided architectural freedom through the curves, shapes and heights achievable as well as the feature walls - one of which has been made to look like the ripple of a pond.

"To be able to build something like that through traditional building, you can, but it's really tricky and it takes skill, time and money to be able to do that.

"The great thing about 3D printing is you tell the robot what to do and it does what it's told."

Gordon said the walls were about twice the width of ones in a standard timber-frame house, and all included foam insulation in the cavity, unlike in traditional housing.

"We're really excited to see what that acoustic rating's going to be and what the thermal rating's gonna be once we've got the house.

"On the outset we've had some scorching days lately and the house has been all closed up and when you walk inside it's at a fairly cool and even temperature which is nice."

He said the build cost was comparable to current average prices of about $3500 per square metre.

The 3D printer and factory are owned by Wafaey Swelim, who was in Texas with two of his workers helping a company with a 3D printed nine house complex.

Iconic and Qorox have also built at least two homes, part of a skate park in Tauranga, walls for offices and even retail outdoor planters and seating that double as ram raid bollards, and had an arm in Christchurch.

Master Builders chief executive Ankit Sharma said the technology was important for construction because the industry must build better quality, resilient and sustainable homes, resistant to increasing extreme weather events while addressing affordability.

"We need to find a way to make housing more affordable and technologies like 3D printing and pre-fabrication can reduce labour costs, they can reduce material waste and reduce construction time which can significantly reduce the cost and the time it takes for us to build homes."

He said building consenting authorities and legislative framework must now adapt and the workforce had to be educated and trained in building with 3D printers.

Minister for Building and Construction Chris Penk said the government was taking a keen interest in the technology.

Construction costs were too high and the Government was determined to bring them down.

He said the government was keeping an open mind about the possibilities for social housing, with Ireland having just completed the first ever 3D-printed council housing complex.