A house built in the early 1970s for just $17,000 has been recognised four decades later for its sustainability.

Adelaide architect Rod Roach designed and built the Belair house for himself, filling it with experimental design features.

It has proven to be an enduring example of his style, winning the Derrick Kendrick Award for Sustainable Architecture at the 2013 South Australian Architecture Awards. Roach described the win as a “surprise”.

“I didn’t even enter the competition.”

He says he sold the house to an architect, who then sold it to another architect, the current owner, who entered it in the awards.

The fact that the house has continued to be favoured by architects is in itself a tribute to the timelessness of its design.

Roach says his original design was dictated entirely by the budget.

“Since it was the first house I ever built, it had a very tiny budget, $17,000.

“It was a simple design. We dug into the side of the hill, which saved the cost of building a length of wall.”

Simple materials were used to keep costs low.

“We excavated the site, put in a bench slab, and poured concrete for the floor.

“It has brick walls and a gently sloping timber-framed roof with metal decking on top.

“It had some pretty radical features for the time. We used floor-to-ceiling windows, which wasn’t done often in smaller houses back then.”

The house has a north-west orientation, allowing it to catch the early morning sun in winter, but avoid the sun’s harsh gaze during the summer months.

Roach says he’s not sure what the other owners have done with it since he sold the house, but in his original design dark carpet covering the floor absorbed the heat of the sun during the day, and then radiated it back out at night to warm the house.

Another unusual feature was the round toilet.

“It had a tube window that extended through the sloping glass, and it looked into the garden, which was very interesting.”

Roach says some of the property’s best features came about because it was his own home, and he wasn’t designing to a client’s brief.

“You wouldn’t be able to do some of those things for a client, as you have to be so cautious. But because it’s your own house, you can experiment.”

He says the house is timeless because of its clean lines.

“My architecture is inherently very simple; I don’t go for fancy forms and shapes. These days, architecture uses every single kind of material, but I like simplicity.

“Some of those trendy materials and colours do date. This house is just white. It doesn’t date.”

Despite being proud of this house, Roach says he hasn’t gone back to see it in recent times.

“I rarely go back into buildings I’ve done previously. It’s the fun of the construction; after that, it belongs to someone else … particularly since I’ve sold the house.”

Subsequent owners have added their own touches to the house. An extension has been built, along with a swimming pool.

Roach says they added “all those lovely features I couldn’t afford back then”.