The numbers continued to increase rapidly, and in 1884 the Charity Commissioners agreed to the proposal of the Governors to extend the Class-rooms. Those already standing had been built in such a way that it was an easy undertaking to add to them. The road up High Rigg alone stood in their way, but permission was obtained to divert it and make a better road further South. On the ground-floor two new Class-rooms were built and connected by a corridor on the West side, while above it Big School, eighty feet long by thirty feet broad, absorbed one of the former Class-rooms, and supplied what had previously been a great defect in the arrangements of the School. It was capable of holding between three and four hundred people, and was thus of the utmost use on Speech Days and other great occasions, besides providing a fit place for assembling the whole School for Prayers and Concerts. At the southern end of the building a transverse addition was built, of which the lower half was to serve as a Library, and above were two Class-rooms opening into the Big School. Thus in addition to the Science Block, the School Buildings now consisted of Big School and nine large Class-rooms, each of which was capable of holding from twenty to twenty-five boys. Another long-felt need was also supplied. A large Covered Playground was erected on the West side of the Class-rooms. It was one hundred and five feet long and fifty feet broad, with a height of forty feet; its floor was paved with wood, and its walls were cemented. There a large proportion of the School could amuse themselves on days when the inclemency of the weather made out-door pursuits difficult. The cost of these buildings was defrayed out of the Trust Funds, but at the same time a Gymnasium and Changing Room were added by money provided by the subscriptions of Old Boys and other friends of the School, and in particular of Mr. John Birkbeck, one of the Governors. The cost of this part alone amounted to over £1,300.
The twenty years from 1866 to 1886 saw the whole character of the School transformed. A complete set of new buildings had been erected with boarding accommodation for one hundred and fifty boys, and Class-rooms for two hundred and forty, all within one central space. Over twenty thousand pounds had been expended, and yet it had been found possible to meet these many claims without unduly depleting the total revenue arising from the Estates in the possession of the Governors in the East-Riding. The rental in 1894 was over £700, and shewed a decrease of a little less than £500 a year. That such a sudden and swift development should have been possible reflects the greater credit on the foresight of Sir James Kay Shuttleworth and his fellow Governors and on the energy and enthusiasm of the Headmaster.