The St Albans-based contractor will build a new three-storey teaching block at Hounslow Heath Junior School on Cambridge Road, Hounslow.
The extra 2,000m2 of floor space will provide an additional 14 classrooms for the expanding school.
Borras’ £9m contract also includes some remodelling and refurbishment of existing school buildings.
Got a story? Email news@theconstructionindex.co.uk