When the small community of Kiah, on the NSW far south coast, was engulfed by bushfire on January 4, it seemed unlikely that Sue Norman and Mick Harewood's timber cottage would withstand the blaze.

"Everyone thought our place would be the first to go," Ms Norman said.

"It's a weatherboard house, built in the 1890s, and it's right in amongst the forest. The forest has grown up around it."

The couple had modified the cottage to make it less vulnerable to ember attack, but for Mr Harewood, the crucial reason the house is still standing is the bunker they built following Victoria's Black Saturday bushfires.

"If I didn't have the bunker, I would have had to leave. I wouldn't have been game to stay here," he said.

The 1890s timber cottage seemed unlikely to survive the blaze that engulfed Kiah. ( ABC South East NSW: Vanessa Milton )

"It meant that I could turn on the sprinklers at the opportune time. If we'd turned them on at 8:00am and driven away, it would have wet down the house, then it would have dried out again and the fire would have taken it."

When the couple began researching fire bunkers, there were few official guidelines.

"We found out that the CSIRO had investigated bunkers, and basically stopped investigating them, because people died in them from carbon monoxide poisoning," Mr Harewood said.

"A bunker has to be gas-tight."

Theirs is built into a hillside about 25 metres from the house, constructed of terracotta bricks below ground level and mud bricks above, with a concrete floor and ceiling.

It is impenetrable to gases and equipped with external and internal temperature gauges, a carbon dioxide meter, compressed air tank, a barometer to monitor air pressure and a valve to release air if the pressure builds.

The couple built their bunker after the Black Saturday bushfires in Victoria. ( ABC South East NSW: Vanessa Milton )

A small ceramic glass window was a big investment but crucial for judging when it was safe to leave the bunker.

It was designed to provide refuge for two people, but Ms Norman decided at the start of this bushfire season that she would leave and get out early.

"I'm really glad I didn't stay, because I only would have got in the way and I didn't want to experience that fire," she said.

"There are people who did stay in Kiah who had a hell of a time and are lucky to have gotten out alive."

The couple made some additions to their bushfire survival plan as the season approached. ( ABC South East NSW: Vanessa Milton )

At 10:00pm on January 4, Ms Norman called Mr Harewood to let him know the fire was approaching Kiah and he went into the bunker.

For the next 90 minutes he remained inside, peering through the small window to watch fires igniting just metres away.

Mick Harewood spent 90 minutes in the bunker as the fire raged outside. ( ABC South East NSW: Vanessa Milton )

"I could see fire creeping down the hill, but in the background it was raging — the whole sky was red, it was alive with fire," he said.

"When I came out the power was off to the house, the sprinklers had failed, the smoke alarm was screaming, and there were lots of little fires all around; anything that could catch alight was alight."

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 1 minute 30 seconds 1 m 30 s Mick Harewood's view from the fire bunker ( Supplied: Mick Harewood )

The historic timber cottage was still standing but Ms Norman's studio was burning out of control. The mud-brick walls of the studio had withstood the fire but a timber door succumbed to sustained ember attack.

"It was burning from the inside," Mr Harewood said. "There was black smoke fuming out of every opening."

Sue Norman's beloved studio was left in ruins. ( ABC South East NSW: Vanessa Milton )

The studio contained a lifetime's worth of artworks, books and research — now reduced to ash.

But Ms Norman remains philosophical.

"It's so much harder now to feel safe in an environment like this, or anywhere really, so we've all got to get used to letting go of material things."

She said she was interested in the stories held within the objects and the new story they now told.

"As humans, we've reached a pinnacle of awareness and ability, and we seem to be so unaware of where we are and who we are in relation to the world, the environment.

"It will destroy us, and it is."

Sue Norman found her childhood box brownie among the ashes in her studio. ( ABC South East NSW: Vanessa Milton )

More than half of Kiah's homes were destroyed in the fire and the forest is deeply scarred.

"For a week or two after the fire, trees were just falling," Mr Harewood said.

"On the first day, every few minutes there'd be another giant crashing down."

"We've lost big old-growth trees that we'll never see again in our lifetimes," Ms Norman said.

"It's not just here, the landscape all around us has changed forever."