A Sunshine Coast engineer has been sentenced to 10 years’ jail for trying to gas his wife when she threatened to divorce him.

A jury found Robert Ridgeway guilty of attempted murder after hearing he connected a garden hose to his wife’s caravan and subsequently pumped nitrogen gas into the van as she slept in 2016.

The court heard Ridgeway’s wife, Pepita Ridgeway, only managed to escape after she heard a hissing noise inside the caravan on the night of July 5.

She found a hose taped underneath her mattress, and traced it to a gas cylinder in the family’s carport.

The judge labelled the attack “cold and callous” in sentencing Ridgeway to 10 years’ jail in Brisbane’s Supreme Court.

In sentencing, Justice Glenn Martin told the 64-year-old “there was nothing spur-of-the-moment in this”.

“This was something you obviously thought about and you thought about carefully,” he said.

The jury was presented evidence that Ridgeway had purchased tools and equipment to build the apparatus after his wife sent an email in the days prior, threatening a divorce.

“You were seen working near the caravan,” Justice Martin said.

Ridgeway then, “engaged in research on the internet with respect to the properties of nitrogen”.

Pepita Ridgeway heard a hissing noise inside her caravan and traced it to a gas cylinder. Photo: Facebook

‘No remorse shown at all’

“There has been no remorse shown at all,” he said.

“[Your wife] may as well have died gasping for air.”

Ridgeway has been in custody since August 2016, but must serve at least 80 per cent of his sentence before he can apply for parole.

The court heard Ridgeway had no prior convictions, but the judge did indicate this was an “unusual case” as there was no evidence of “physical violence” in the attempt to murder.

Justice Martin told Ridgeway he was “clearly an intelligent, well-qualified man”.

It took the jury just over an hour to reach its verdict on Monday, after hearing almost two weeks of evidence.

Ridgeway had pleaded not guilty to the attempted murder charge.

-ABC