 Because of the structure of the school board, Blacket's plans for the extension had to go before the Legislative Council for approval.He added a wing to either end of the building, respecting the proportion of the original, but with two floors where the earlier stage had one, and with the centre of Hallen's building having a Doric portico.The portico was not constructed until 157 years later, and in the intervening period, the design looked strangely vacant in the middle.