Engineers working at Spencer Court say the recent wet weather has put their work to the test.
The flats in Newburn were demolished after rain caused a culvert to collapse, washing away the ground underneath.
Boulders put in place to support the construction work are withstanding the current wet weather but there are fears more rainfall may cause flooding.
Site staff say the next 48 hours are critical.
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Stockton Stages takes place from Thursday, July 20 to Saturday, July 22 in Stockton town centre.
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