Mr Barber was encouraged to enter the apprenticeship awards by his boss, Willie Hepburn.
He completed "a whole big profile about myself" and attracted the attention of the judges.
His assessment was based on interviews with three judges at sponsor Carters, and a visit to Mr Barber's worksite at the time - a large "brand new family house" in Gladstone, with a huge 350sq m floor area.
"I was showing them around, talking about the job and the parts I had worked on," Mr Barber said.
Judges checked out his interests, experience and knowledge.
He was asked about everything from his knowledge of building codes to his favourite building materials and tools.
For this last, there was only one answer - the nail gun. "It's a pretty handy tool."
Registered Master Building Apprentice chief executive David Kelly said the outstanding group of contenders this year reflected a real commitment from the construction industry to apprenticeships.
"It's been fantastic to see the skill and commitment of these 145 young apprentices as they make their way towards becoming Master Builders," Mr Kelly said.
"It's safe to say the future of the construction industry is in extremely safe hands and the public should be reassured that these young people are intent on achieving the very best quality in their craft."