A proposed boarding house for 27 independent school pupils in Brighton has been turned down on appeal.
Brighton College already puts up 18 students at the three adjoining houses in Walpole Road but wanted to knock them together.
A planning application setting out the proposal was turned down by Brighton and Hove City Council in July 2023.
The independent school wanted to join the three properties and extend the living quarters into the roof.
The council said that the plans were “an unacceptable intensification in the use of the site” and the bedrooms were not big enough.
When the school appealed, the council said: “Even if all three properties were in domestic residential use, a likely occupancy would see approximately 12 persons across the three properties (four per dwelling).
“The application proposes 27 pupil spaces, not including staff, which would present far more than a doubling in occupancy from that which could reasonably be expected in such a location by the adjoining occupiers.
“In addition, the removal of the internal divisions and the amalgamation of the rear garden would create a property whose occupancy, operation and internal form would be significantly different to the prevailing character of a terraced residential street and would likely remain as such.”
After an enforcement visit, Brighton College said that the works already carried out, including the creation of one back garden and the removal of internal walls and some rear bay windows, could be reversed.
Brighton College’s planning agent, Lichfields, helped the school to prepare an appeal statement which said: “Comings and goings from the boarding houses would remain limited by safeguarding measures and restricted by timetables.
“Pedestrian movement from pupils in Walpole Road is therefore managed and would not harm the character of the street.
“The increase in pupil occupation is not considered by the appellant to give rise to additional activity that makes the development unacceptable in planning terms.”
More than 80 people formally objected to the appeal.
Planning inspector Robin Buchanan said that noise from the communal garden could adversely affect neighbours.
Mr Buchanan also said: “In addition to harm to the character and appearance of the area, including the CCA (College Conservation Area), there would be adverse impact on the living conditions of some residents of adjoining houses and an unacceptable standard of bedroom accommodation for some pupils.
“Ensuring satisfactory outcomes in both of these respects should be the aim of new development from the outset.”
