Victorian re-evaluation: Threefold's mixed-use retrofit
Technical & Practice: This once-derelict Victorian corner house in east London now houses a gallery, office space, and a glass box with views of the City, writes Jack Hosea. Photography by Charles Hosea
Threefold Architects was invited to reinvent and extend this Victorian building in Whitechapel, east London. The urban and historical context of the site is fascinating. Located on the fringes of the City of London, whose skyscrapers dominate all westerly views, it stands on the north-east corner of a derelict Georgian square owned, and due to be demolished by, the London Development Authority.
Demolition was staved off by the Spitalfields Housing Trust, a group of individuals who bought and restored the properties on the square to help regenerate an area facing rapid change, with the redevelopment of the Royal London Hospital happening just around the corner and the Olympic Park not far to the east. In this setting, the corner building that we worked with stood out like a Victorian sore thumb until our client acquired it and set about its transformation.
Together with the client, we devised a mixed-use programme for the project, creating an active street front with an office and gallery space on the ground and lower ground floors, and two separate residential units on the first, second and new third floor. Our approach involved sympathetically restoring and enhancing the building’s existing fabric, making bold spatial changes distinct from the original - all on a tight budget (£1,457 per square metre).
Basement and lower floors
In order to lower the level of the existing basement storage area, the structural engineer devised a strategy for excavating to the bottom of the existing corbelled foundations and then casting a new slab at this level. This increased the headroom by 500mm and enabled us to transform the basement into a usable floor without the need for costly underpinning.
We removed a series of internal partitions to create large open-plan spaces on the previously cellular ground and basement floors and cut holes in the ground floor to create a double-height space.
Office and gallery space finishes are raw, with polished concrete screed, white walls and frameless glass balustrades. These create flexible, reconfigurable spaces, bouncing light around and acting as backdrops to the art and design exhibits.
The second floor contains a bathroom and two bedrooms, separated by a sliding folding acoustic partition that allows the space to be completely opened up if desired.
The same palette of white oak flooring and white painted finishes extends to the stairs.
In order to add a new storey we had to engineer the third floor and construct it as a ‘crash deck’, robust enough to support the potential collapse of the new storey above. This was achieved by a primary steel structure spanning the existing masonry walls with timber infill joists and a plywood diaphragm.
We wanted a seamless, crisp glass box, with no external framing or visible roof, set back from the building edge inside the line of the existing masonry walls. The key to this effect was column-free corners and flush silicone-jointed glazing.
We made these column-free corners by introducing a steel and timber diaphragm roof structure supported by cylindrical columns, set back from the glass walls. These were in turn supported on a steel ring beam set inside the existing masonry walls within the new third floor structure below.
Our client wanted to ‘live in a glass box’ with views out, and in, on all sides. This generated a luminous open-plan living room and kitchen, opening onto a west-facing terrace with panoramic views of the City. The flush-glazed appearance was created using a facade system, with glass panels structurally bonded to the outside of thermally broken PPC aluminium mullions that span from floor to ceiling. We back-painted the top section of each glass panel and ran it all the way to the top of the hidden parapet to obscure the roof build up behind.
Double-glazed units with argon-filled cavities and solar control coating, as well as concealed roller blinds, help to limit solar gain. Flush-glazed opening windows and the fully opening west facade provide cross ventilation and exhaust hot air.
The lively acoustic of the glass box was dampened by ceiling panels that form a crisp border to the ceiling perimeter. Underfloor heating avoids the need for radiators, keeping the space and perimeter walls free from clutter. Internal finishes use a simple palette, with engineered white oak flooring, white plastered ceiling, white Corian kitchen and white spray finish joinery.
Jack Hosea, director, Threefold Architects
AJ Buildings Library
Start on site August 2009
Completion January 2010
Gross internal area 175m²
Construction cost £225,000
Cost per square metre £1,457
Contract JCT Minor Works 2005 with contractor’s design
Client Mark Ford
Structural engineer Heyne Tillett Steel
Second floor bathroom and basement storage wall designer Emoli Petroschka
CDM coordinator MLM Consulting Engineers
Approved building inspector MLM Building Control
Contractor PMB with Hi Spec Build
Glass extension contractor Ridlands
Joinery DGM Joinery
Acoustic sliding folding partition Niche
Flush glass facade system Schüco FW 50 SG
Acoustic ceiling panels Soundsorba
Kitchen surfaces Corian
CAD software used Vectorworks
Annual CO2 emissions Not calculated