The hand-forged nails; the bricks made on site. And the spiral staircase in the homestead that hardly makes a noise as you climb it.

“To think it’s [the staircase] been done by hand and the workmanship in it, it’s just amazing,” he said. “All the joints are still tight. The integrity of the stairs is amazing. They barely even squeak.”

Mr Harris, originally from the Tweed district, moved south with his family about six years ago into a 125-year-old home in Lithgow, so he knows his way around an historic property.

But his house looks modern when compared with the homestead and two-storey convict barracks on the property Macquarie, between Bathurst and O’Connell, which is owned by Paul and Bonny Hennessy.

The homestead and barracks were built between 1822 and 1824 by convict labour on 1000 acres of land granted by Governor Lachlan Macquarie to William Lawson for his role in crossing the Blue Mountains with Gregory Blaxland and William Charles Wentworth.

The property remained in the Lawson family until 1918, when it was sold to the McKibbin family, and was sold to the Hennessys in 2012.

With the finishing touches being put on the work on the homestead, Mr and Mrs Hennessy’s attention has turned to the barracks – which is where Mr Harris and his sons Ben and Sam, of BJ Constructions, come in.

“It would be the oldest building that we have worked on,” Mr Harris said.

“From that point of view, we are quite amazed at the resourcefulness of the guys that built it given the fact that the majority of convicts would have had just limited skills, though they were probably trained and overseen by someone.”

Though all the work would have been done by hand, the attention to detail is extraordinary, according to Mr Harris.

“There is more detail than what goes into construction now,” he said.

The timber used by the convict labourers in their construction might be 300 or even 400 years old, according to Mr Harris, considering the trees would have been mature at the time the work was being done in the 1820s.

 “And it was all cut by hand with a cross-cut saw,” he said.

That timber includes a beam running the full length of the homestead that, according to Mr Harris, has “posts coming off it like the masts of a ship”.

Mr Hennessy said it was important to find the right people to do the work.

“My wife and I, as owners of this very historic property, regard ourselves as custodians and curators,” he said.

“In restoring this property, it’s critically important to us that we have tradesmen, particularly builders, who are empathetic to the significance of this heritage property.

“Bonny and I believe we are extremely fortunate to have Barry and his two boys restoring the convict barracks and finalising the restoration of the homestead.”​

Of the many contractors and tradesmen who have worked on the historic property Macquarie, some are descended from the convicts who lived on the spread of land more than 150 years ago.

Macquarie owner Paul Hennessy says the barracks on the property, which is in the process of being restored, would have housed up to 28 convicts at a time.

“Half would have been Irish and they would have been rural workers,” he said.

Most remained in the district once they were emancipated as a condition of their release and were required to report to local authorities.

“So they put down roots,” Mr Hennessy said.

Some of the familiar names among the Macquarie convicts include Tobin, Hogan, Cosgrove and Jennings.

“A number of the contractors that have worked for me [in the restoration of the Macquarie homestead and barracks] are descendants of those convicts,” Mr Hennessy said.

Though the upper storey of the barracks would have been used to store hay, Mr Hennessy and his wife Bonny have made a recent decision to convert that space so it can be used for accommodation, with its own kitchen and bathroom.

He does not plan to offer the barracks accommodation for paying guests, but said that might be an option for subsequent owners of the property.

Mr and Mrs Hennessy have paid for the restoration work on Macquarie without government support.