Underground voids at Greenlane beneath one of Auckland's largest apartment projects created issues at the start of works and resulted in extra materials and expense to fill them in.
Rod Croon, vice-president and acting chief executive of the Auckland Trotting Club which is developing the 246-unit Alexandra Park apartment scheme, today revealed new details about ground conditions when construction started.
"They did find rock and it was a major problem at the start and there were voids in that rock. It was common knowledge," Croon said of the site near the volcano, Maungakiekie.
"I don't know if there were caves but there were problems with the rock and I'm told there were voids. I'm only telling you what I was told," he said, referring to others who had since left the club or had died.
Dominique Dowding was the club's chief executive and closely involved in the project. The late Kerry Hoggard was president and Croon said yesterday: "Kerry was the president from 2012 to 2015 when this whole thing was put together."
Croon said the action was taken once the voids were identified.
"As far as my understanding goes, they [the contractors] filled it with concrete. They filled the voids in the rock," he said, explaining how foundations were redesigned and re-engineered part-way through the job.
But he emphasised he was not closely involved in the scheme around five years ago when the ground issues came to light.
"I wasn't on the board then, I was just a member. This was probably before 2015, maybe in 2014," Croon said of the void discoveries.
Asked if those could have been lava caves, Croon could not confirm that.
Asked if the tall apartment towers could be endangered due to being built on sites where underground voids had been discovered, Croon strongly denied that: "No, it's exactly the opposite. Instead of normal, it was double what it should be. It was over-designed and it cost a lot of money."
Croon could not specify dollar figures, citing his lesser role with the Auckland Trotting Club at the time.
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He also stressed that ground testing had been conducted before Canam Construction and Ganellen began building.
"I'm sure they would have known because they did a lot of drilling," he said, also citing the proximity to Maungakiekie.
A worker on the site said today that the cavity discoveries took crews by surprise and "hundreds of cubic metres" of grout and concrete which cost millions of dollars extra were used on the site after caves were discovered during the earthworks phase.
"They found rooms 2m, 3m, up to 4m high by 2m wide under the ground which had to be filled and stabilised for the foundations. We don't call them caves but cavities," he said.
The new foundations could only be driven down once the huge voids were filled and stabilised, he said.
"When you have lava flows, it's not uncommon to find cavities because sometimes the lava solidifies but other times it doesn't," the worker said.
Croon said today of Building A: "It's due to be finished by Christmas but the official date of practical completion is February 28, 2020. For Building B, practical completion is April 30, 2020."
Previous marketing material indicates some apartments were due to be finished by 2017.
Tonight at 6.30pm, club members hold a special general meeting to vote on a proposal to sell two Manukau Rd sites, estimated to be worth $20m to $23m.
That is needed, Croon said, to cover $40m debts to ANZ and Westpac, due to be repaid next year.
The club had expected a $30m profit on the project but is now faced with asset disposals to cover debts.