A heritage assessment supported the approval of a roof extension for Brock House, a former BBC office in central London. Originally opened in 1908 as the Philharmonic Hall, the building features red brick and Portland stone and is located in the Harley Street Conservation Area. It sits near notable landmarks such as BBC Broadcasting House, All Souls Church, and the Langham Hotel.
During the pre-application process, heritage and townscape assessments helped shape the proposal for the roof extension, which was later included in the planning application. The Conservation Area Appraisal recognised the building as a suitable candidate for a roof extension, noting that it aligns with the character of other townhouses in the area. Many of these buildings have replaced their traditional butterfly roofs (hidden behind parapets) with mansard roof extensions.
The design was carefully considered in the context of the area’s diverse architectural styles, which include Gothic and Flemish influences. It also drew inspiration from the Arts and Crafts details of nearby Victorian mansion blocks on Great Portland Street. The heritage statement confirmed that the design was compatible with the building’s scale and architectural style.
The proposed mansard roof, modern yet respectful of the building’s Classical design, adds an extra storey with a gently sloping form. This extension would enhance the skyline between Great Portland Street and Oxford Street. The lightweight, double-storey addition complements the unique roofline of the adjacent church, maintaining harmony with the historic surroundings and contributing to the architectural cohesion of the area.
2018, approved mansard