Permitted Development from B1 Offices to C3 Residential to create 24 appartments and 2 town houses Cowan Architects secured a first with the ‘Prior Approval’ for the conversion of a 2,025 sq.m. office building, Phoenix House in East Grinstead, West Sussex, into 24 self-contained flats under the new General Permitted Development Order 2013 (GPDO 2013). This was one of the first instances of a project of this size in Sussex to gain ‘Prior Approval’ under the Government’s new GPDO 2013 and it sets a benchmark for other potential projects of this type and scale in the area. Arranged over three storeys, the approved scheme offers 18 two-bed flats, 3 one-bed flats and 3 studio flats. Further to the ‘Prior Approval’ we gained permission to add 2 new town houses set adjacent to the Western elevation of the existing building. The town houses are 3 storey with a bedroom ensuite on the ground and first floors, with open plan living spaces on the top floor. They were designed in a way as to complement Phoenix House in materiality although a more contemporary design allows the town houses to read as later additions. A further separate planning permission was also achieved to convert the existing plant rooms at roof level into penthouse suites.