In front of accompanying media she and Ardern commiserated.
"We need more females," Young-Cathcart said.
"I was the only girl in my metalwork class in Year 10," Ardern replied, nodding. "I totally understand what you are saying. I won a prize for metal work that year. That didn't go down so well."
Foreign Minister Gerry Brownlee is a former woodwork teacher, and Ardern said the only reason she didn't pursue her talent for metal was because it clashed with other subjects.
"There was an assumption that you either went down one path or the other when I was in high school."
After Ardern moved on, Young-Cathcart said it would be cool to see her as PM - and attempts to attract more women into the trades work out.
"Then I can actually talk to people, instead of talking to boys all the time."
Despite her high school achievements (and more recent form installing her toilet against local regulations) Ardern quickly and politely declined an offer to help put up some weatherboard.
Former Prime Minister John Key's "nail fail" effort to put up a hoarding in the Northland byelection was perhaps fresh in the mind of advisors.
In the afternoon Ardern travelled up the motorway to Te Puea Marae, which has been sheltering people without accommodation for a second winter.
She was joined by deputy Kelvin Davis and shared kai with families staying there, but behind closed doors in a rare campaign stop not open to media.
Afterwards, she said there were four families currently on the marae, including 19 children. It was her third visit to the marae, which has received government funding.
"They don't want to be a long-term solution for people. The family I visited with had been in a hotel unit for weeks and weeks and weeks. And it's just not the kind of place that is suitable for kids."
