That was especially difficult for Sullivan, as he took part in the challenge while in isolation due to Covid-19.
He competed in the challenge last year, but said this year was very different as being in isolation meant he had no way of gauging how he was progressing compared to the other apprentices.
Despite these challenges, Sullivan's bench came out with the highest overall score, earning him the title of regional champion and a $500 ITM gift voucher.
However, at the end of the eight hours, Sullivan was mostly hoping for a rest rather than jumping for joy.
"I was pretty tired to tell you the truth," he said.
Sullivan is completing his apprenticeship at Craig's Building in Marton, whose workshop he used to complete the challenge.
Company owner Craig Whitton said Sullivan had been a big help on jobs.
"He's a good bloke and he's quite good to have on the sites."
The 32-year-old previously worked in joinery, putting together kitchens and furniture.
Sullivan said the reason he moved to a builder's apprenticeship was that one day he hoped to build his own house.
"My goal in life is to build my own house, and the only way to really do that is to become qualified and learn the trade."
His regional win gives Sullivan the opportunity to take part in the national Builders Apprentice Challenge in November at NZCB's annual conference. He will compete against 19 other apprentices in another eight-hour building challenge for the Ken Read Memorial Trophy as well as $25,000 worth of prizes.
Ahead of the competition, Sullivan said he would study building methods and the competition itself to prepare. However, the participants are given the brief for what they will be building on the day of the challenge, so there was only so much he could prepare for.
"I've just gotta stay focused, don't open my mouth really and just stay focused," he said.
Sullivan said he was thankful to Craig's Building for his apprenticeship and giving him the workshop space to complete the challenge.
The benches built by Sullivan and the other contestants are being auctioned with all proceeds raised going to the Cancer Society.