The prefabricated rooms are built on the company's Arrowtown site and trucked to locations around the South Island, which architect Maarten Hofmans said was an "instant answer" for what was an increasing home ownership market for Space.
The company started off building the rooms, varying from 3m x 3.7m to 3m x 7.5m in size, for farm accommodation, add-on offices or in some cases retail prefabs.
Mr Hofmans, also the owner of Hofmans Architects in Arrowtown, and his partner Chris Cerecke have now expanded the business in response to calls from customers for home extensions and small cottages.
The rooms are an affordable way for young couples and those with mortgages to extend homes because it allowed them to "stage-build". The units can range in price between $20,000 and $70,000.
"It's a good head start for those that can afford a section but can't afford the rent, the mortgage.
"You can at least get something on the section and get a head start."
General manager Ben McGill said by building the units on site it "eliminates external factors" such as working in the weather, a common problem for Otago-Southland builders.
Transportable units have typically been the likes of school prefabs and with quality often compromised, but Mr McGill said they had tried to market themselves as the middle ground.
Since the recession, the size of many homes had been reduced which left an opening for smaller, quality buildings that could be taken with you, he said.
The rooms, once on site, were bolted down to the prelaid concrete pads or screw piles and connected to water and power facilities.
Mr McGill said a growing market for their product was coming from Christchurch, but land zoning and insurance issues had slowed that market.
Interest from the North Island has led Mr Hofmans and Mr Cerecke to expand the business.
However, Mr Hofmans said there was still a "ferry-crossing hurdle".
The units' basic design is based around Arrowtown's historic precinct of the railways' and gold-mining cottages and they are built from traditional materials of insulated, prenailed timber frames, insulated sandwich panel floor, rubber-membrane or long-run roofing, and double-glazed windows.
They are clad with cedar or Zincalume on a cavity. The inside is lined with plywood and whitewashed.
