The developer of one of Sydney’s largest apartment developments at Castle Hill, which had signs of cracking in a basement, will provide $11 million in security to fix any future defects and has agreed to guarantee its structural integrity for the next two decades.

Toplace’s commitments for the $900 million Skyview towers has led to NSW Building Commissioner David Chandler lifting an order which had prevented the developer from settling with buyers of off-the-plan apartments in two of the five buildings in the complex.

Concerns about the development on Old Castle Hill Road were first raised in April when inspectors found signs of cracking in the basement car park between two of the towers under construction.

Mr Chandler slapped a prohibition order last month on the project’s first two towers, following the earlier inspections by Fair Trading and a notice issued by private certifier City Plan Services requiring independent engineering advice.

In a report released on Monday, the independent engineers concluded that rectification works and ongoing monitoring and maintenance meant the cracks in the basement will not “affect the integrity and overall performance of the building”.