Davor Popadich, a director at Pattersons Architects in Auckland, New Zealand, never dreamed that he and his wife, Abbe, who runs a small home-furnishings importing company, could gather enough funds to design a home of their own. They figured their chances of finding a vacant site within reasonable distance of their workplaces downtown and having enough money left over to build a house on it were almost zero. “There’s no way we ever thought we would be building,” says Abbe. “It was just too expensive.”

In 2008, the couple decided to move out of their central-city studio apartment and look for an existing home they could purchase and renovate. After two unsuccessful bids on small properties on Auckland’s North Shore, about five miles from downtown, they made an impulsive offer on a small site in the coastal area that had been subdivided from a larger property. When that was accepted, they faced a hard fact: They had just $187,000 left with which to build their new house. “I remember saying, ‘We could live in a half-finished house,’ ” notes Abbe. Adds Davor, “We’re quite stupid like that.” In the end, Popadich’s inexpensively exe-cuted building concept, based on a simple, pitched-roof boat-shed form, proved to be very smart.

Abbe: We really only looked at this site because we were intrigued by it, as sites hardly ever become available in this area. We thought we’d make an offer because we were almost certain it would be turned down. Then our offer was accepted and we thought, “Goodness—we’re going to need to put a house on that.” So we had to go for it and start the process of building.

Davor: The site is small but flat, so I was able to see some possibilities for it. I worked on the design in my spare time for about a year. I loved doing it—I was really on a high throughout the process. Early on we decided we liked the idea of a house inspired by boat sheds, because we thought it would be economical to build and would look appropriate for this seaside suburb. I designed two slightly offset double-height modules with the same dimensions, with a steel portal frame supporting them. One has a mezzanine bedroom with the kitchen and dining area below while the other has the entry, bathrooms upstairs and downstairs, and a double-height living space. Then the building estimate came in at $285,000 and I came down off my high pretty quickly. I had to modify the plans so we could get closer to our budget. The bank was only going to loan us $187,000—there wasn’t any room for cost overruns.

A couple of key changes meant big savings. Initially, I had specified commercial-grade aluminum windows and doors, but then I realized that settling for a cheaper range would save us another $22,000, and it didn’t look too different. I also went to meet the window fabricator and worked with him on devising a window structure that would be simple to make and that would use materials efficiently and cheaply. We had planned on installing an under-floor heating system in the concrete floor slab, but we took it out in the hope that there would be enough solar gain during the day and insulation in the walls and ceilings to keep the heat in. We were right, and we saved about $6,000 by doing that.

There were other ways we saved money. We got more competitive quotes from plumbers and electricians, and saved about $8,000 by shopping around. In the design, I had originally specified the ridge beams as steel, but it turned out to be cheaper to do them in timber. I didn’t mind as long as we kept to a simple materials palette: timber, ply, and a bit of steel. We chose corrugated, prepainted aluminum sheets for the external cladding because they were relatively cheap and robust. Everything was measured and sized exactly so we didn’t order any more materials than we needed. I detailed the house so its construction would involve as few tradespeople as possible. For example, the internal doors, the built-in seats, and the bathroom and kitchen cupboards were all made onsite by the builder—and the built-in seats saved us money on furniture. And we decided to line the interior in exposed plywood sheets—on paper, plasterboard seemed cheaper, but then we realized it would cost money to plaster and paint it, which pushed the overall cost up. And the builders liked that, because they got to show off their workmanship, which is usually covered up by plaster and paint.

I designed the house as a two-stage build—the scheme has a lean-to structure containing a garage and two bedrooms on the southern end of the house, but we decided to build it at a later date to make the house affordable to begin with. The house is 1,184 square feet now, and the addition, when we eventually do it, will add another 348 square feet of living space, plus the garage. Partway into the design process, we found out Abbe was pregnant [the couple’s son, August, is now two years old]. We couldn’t afford to make the house any bigger at that stage, so I designed a spare bedroom in what was originally planned as our walk-in wardrobe so the baby could sleep there. We’ve been in the house over a year, and now we have a new baby, Violeta, so it looks like we might have to try and build the addition sooner rather than later.

Abbe: Davor was really careful about the form of the house, and I was focused on how we were going to live: where we were going to sit at night and how we were going to relax. I wanted window seats—I imagined our perfect life as starting the day with coffee on a window seat in the sunshine. The whole process forced us to think about how we wanted to live, which was great. Normally, you move into a house that someone else has designed and just live with it, and not ask yourself these questions.

Davor: Abbe wanted the house to feel intimate. The warmth of the interior was more critical than the appearance to her. When it came to the design, I really did pretty much the same thing as we would do at work: I treated Abbe as my client, and asked her what the brief was.

We talked a lot during the process about everything to do with the house. It became really enjoyable—in some ways I found having less money gives you more freedom. If we had lots of money I would probably still be trying to decide what to do. If you could have every choice, what choice would you make? This became more about necessity and what was essential. But now that the house is finished, it feels like we have everything we wanted. The beautiful thing about building your own house is that if you get it right it will allow you to live the way you want to.