A two-storey portable building could be installed at Furze Platt Senior School in Maidenhead if plans are approved by the Royal Borough.
The school in Furze Platt Road has been awarded an £880,000 government grant to build eight new classrooms to relocate its maths department.
The new building would be built on a disused playground and is expected to cost £1m.
The remaining cash will be spent on providing more space for sixth formers and pastoral care.
Headteacher Tanya White said: "Through getting the grant we have been able to achieve quite a lot."
"It will mean first of all we can have all the maths classrooms in the same area."
She added that subject to planning permission being granted the new building could be open in September.
A decision is due on August 16.
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