Central Auckland’s tallest apartment block is yet to get out of the ground because of flawed concrete in its foundations.

The contractor China Construction New Zealand has been struggling to investigate and fix the defects at the Seascape building on Customs Street East for more than a year.

The five-storey-deep walls of the carpark basement have voids in them and are contaminated by slurry.

Some concrete on the inside walls of the basement has been waterblasted and patched with structural concrete, but the outer face of the walls is buried in earth and has yet to be properly checked.

The 52-storey Seascape had aimed to open its apartments in 2021, sitting on massive piles, a thick slab, and the basement walls that are well below the level of the sea just 200 metres away.

Auckland Council said it was aware of the risk from seawater getting in and corroding the reinforcing steel.

It had allowed carpark floors to be built only up to a mark five metres below ground level.

“At this point we would not allow work to proceed higher unless we are satisfied that area of wall is compliant,” the council said.

The contractor found defects and promised a quick fix back in October 2018 – back then, it said the concrete was “just a bit patchy”.

Fourteen months on, Auckland Council is still waiting for key information about the state of the outside face of the walls.

Asked if whole new foundations might be needed, the council said “no”, but added if the outside of the walls needed “extensive” repairs, then “other options may be looked at”.

It was “anticipated” the outside face of the walls would have the same defects as the inside faces, the contractors and developer said.

But they insisted the defects were isolated, were anticipated, and could be fixed with methods regularly used worldwide.

The walls themselves were being monitored “and these have performed as expected”, the contractor and China-owned developer, Shundi Customs, said in a joint statement to RNZ.

However, construction would not begin above ground until the defects were fixed, they said.

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