The main contractor announced in May that half the concrete frame will be dismantled following the discovery of piling problems on the £65m project.
But BAM has now confirmed that the partially-built structure will have to be completely torn down after starting partial demolition work last month.
The move has caused anger among local residents hit by the noise of demolition work.
BAM said: “We have concluded that the best solution is to deconstruct the entire building before re-building and have advised the residents that these works will conclude in October.
“Re-piling will be complete in early 2021, after which operations will be much quieter.
“We are doing what we can to offset this inconvenience and are restricting the times we are operating the concrete breaking machine which is the noisiest part of deconstruction.
“The technical difficulties that have led to the present situation are highly unusual.
“Everyone’s aim has been to create a building that the University and surrounding community will be proud of and that improves on what was there before.
“Ultimately we will achieve this, just later than originally planned, and will keep doing what we can to reduce disruption in the meantime.”
Main construction work started on the site in May 2019 after BAM replaced Kier who had signed a pre-construction deal for the project but failed to agree a final price with the university.
In its original statement in May BAM said: “BAM identified that there was settlement occurring in excess of that which would normally be expected in a structure of this nature, prompting us to conduct detailed investigations.
“These confirm a problem involving the piling of the structure, which are unusually complicated.
“We therefore conducted a review together with our client and the expert subcontractors involved: Mott Macdonald – structural engineers – and Cementation Skanska – piling contractor.
“This concluded the best course of action would be to partly dismantle some of the current structural frame – to the north elevation then rebuild it. Those works are now underway.”
