His family had moved to the Mangerton home in 1963 but the house under construction a few doors down was different to anything the 20-year-old had seen.

The house, tiered on a steep slope, was a design by modern architect Robin Boyd. It was an outdoors-in, indoors-out type of house - a trend started by Boyd in post-war Melbourne and Sydney in the late '60s.

"I was fascinated because it was hard to see how it was going to come together," says Conacher.

"Until the roof and windows were placed, it was difficult to determine which were the outdoor walls. I was really puzzled by the brickwork. The whole idea of a house like that is to encourage living with nature. In Wollongong, which has such a great climate, that's what we should be thinking about. A house like that has such a great flow."

Conacher was so attracted to the house that when it came up for sale for the first time 25 years ago, he and his wife Fiona McKay, a writer and teacher, purchased it.

They have lived in the "treehouse" ever since, with its internal courtyard, wall of windows and giant blue gum right by the front door.

As the trunk has widened over the years, Conacher has had to cut away sections of the eaves and he will soon have to demolish a small brick wall to allow for further growth.

"I'm going to lose the front toilet," he says. "But the tree is worth it."

It is part of Boyd's approach for his homes to not only blend into the streetscape but to be environmentally sensitive. His designs are also easily adapted to fit the local landscape.

Conacher is mindful of the home's impact on the environment and on his neighbours. When he converted the void underneath the house into an art space for his wife, he built galley-style stairs through the floorboards and a hobbit-type back door so as to blend into the natural surrounds.

That same concept has played a major role in Conacher's work. He has been a co-partner in the Wollongong-based architectural company Borst & Conacher Architects for 30 years. The business has taken out 25 awards, including a national and state award, many of them for environmental and energy-efficiency innovations.

Conacher's father, Colin Conacher, was an orthopaedic surgeon at Wollongong Hospital, who worked 70 hours a week and who died at the age of 62 from a stroke at work. Conacher, who is now 60, has reduced his own pace, partly so he doesn't follow in his father's footsteps.

"I was working up to 60 hours a week a year ago and I thought it was a good time to slow down a bit," he says. "I think every day you're vertical is a good one."

A slower life agrees with Conacher. He has revisited his love of photography and is planning an exhibition in Napier, New Zealand, later in the year.

Conacher has been visiting the seaside village for decades helping to celebrate (as a volunteer guide or lecturer) festivals surrounding the town's art deco architecture, rebuilt following the 1931 Hawke's Bay earthquake.

Conacher attends as the dashing character D'Arcy "Stilton" Cheesewright, a character from a P.G. Wodehouse novel.

He recently extended Cheesewright's repertoire to include a series of public lectures on Wollongong's architecture for the National Trust, of which he has been a member for 20 years. The lecture series includes a "magic lantern" tour of the city's art deco buildings as well as Wentworth Street in Port Kembla. Guests are encouraged to dress for the era.

Earlier this year, he invented a second persona, a retired colonel known as Archibald "Bumpy" Bumpstead. Bumpy will make an appearance in Napier later in the year and in November he will drive a green '30s replica MG billy cart at the Port Kembla Billy Cart Derby.

"It's a lot of fun playing a character and it gives me the chance to be funny and colourful."

In real life, Conacher is just as colourful as his characters. He drives a '67 forest green MG.

"Oscar Wilde said about style that it was 'so awful that it had to be changed twice a year'. For me, architecture is all about good design and the philosophical ideas behind it. Good design never goes away. It's timeless. You see a lot of difference between style and design in cars. The MG, for example, has looked good since the day it was built."

Conacher is best known for his work redesigning heritage buildings.

"I like the idea of recycling buildings because it can save our clients a huge amount of money. With heritage it's about continuity. Re-imagining and re-engineering. Keeping the best of a building and reworking it.

"I take the view that if it's good and it's old and it can be reworked, then why wouldn't you do that. Particularly if there's no loss of efficiency and you can keep a part of the building's character."

Projects include the WEA Illawarra in Wollongong and the revamping of the former Warilla Police Station into a youth refuge. An example of a building blending into its environment is the Acacia conference building at Stanwell Tops. Currently Conacher is working on a 130-year-old farm house at Camden.

"We have clients who we've worked for over and over again," he says. "Which is great because you build up trust and respect. I have clients from the early '80s who I still work with. They keep coming back and it's a real compliment when someone rings you up a decade later and says 'let's do it all again'."

He says programs such as the television reality show Grand Designs scare him.

"Everything goes wrong in that show. I understand you have to have some drama in reality television, but that's not how the business works. It's my job to make sure everything runs smoothly and is under control in relation to time, quality and money."

During his university days, the screen-printing workshop Conacher used was filled with toxic fumes and chemicals causing him, he believes, to develop cancer in 1988.

"It was Hodgkin's disease in my chest. The guy I was working with later died from the same disease."

Conacher is immensely proud of his two children. Davy, 22, is studying environmental science and Shona, 19, is a hula hooper currently performing at the Commonwealth Games Circus in Glasgow.

Conacher says it's been a privilege to have left his mark on the Illawarra.

"I've really enjoyed being an architect," he says. "I like to go to the office and create something out of nothing. To create something that wasn't there before. That's the challenge I've faced every day for the last 30 years."

■ Conacher's next public lecture is at the Illawarra Historical Society Museum on Thursday at 10am, on Sir Humphry Davy, who invented the miner's safety lamp 199 years ago.