This is a speculative office development generating 16,500sqft of retail and work space located at 141-145 Curtain Road, Shoreditch, East London.The project is located within a conservation area defined by Georgian brick buildings and requiring retention of the existing urban block.

The building prior to development was four storeys (G, B+2) in height and is fully remodelled behind a retained brick façade. Above this, three new floors of contemporary office space are added, extending the building to 7 storeys in total, almost doubling the usable area.

To retain the gravitas and independence of the urban block, the additional storeys are designed with an ambition to achieve a lightweight object quality restrained from any references to the adjacent heavy masonry structure. Scale references to the adjacent buildings window punctuation are stripped back by reducing the extension to optimum modules horizontally and vertically. The materials are reduced to mesh and glass with minimal panels and visible jointing. The lack of reveals to windows are intended to further communicate the delicate object form by disguising the depth or make-up of the construction. This object quality is further reinforced by the deep recess to the upper 2 storeys. By revealing a portion of the existing brick flank to the adjacent building block (139 Curtain Road) the weight of the existing fabric is further communicated. This obviously reduces nett lettable area but is counterbalanced by a maximised envelope to the rear. Also the precise fit of the building between party walls without visible overdressing of flashings is intended to allow the extension to read as an independant form intended to appear simply resting 'upon' the facade below and 'between' the adjacent warehouses. A 50mm gap is detailed between the existing masonry and the extension and projecting copings are omitted in lieu of self-draining window sections.

A grid is imposed on the front facade to respond subtlety to the 3 bay house facade below. The plot is trapezoidal in plan and as such a diagonal grid sets up positions of facades and balustrades to the rear. The grid is further enforced at the rear, with smaller staggered terraces, articulating the building where the mass responds to a RoL envelope. Thus a proportional logic of panel size - mesh and glass - is utilised across the facades with the positions of balustrades also defined by the RoL envelope.

The visible facade is made up of mesh and large bonded units. The principle behind the entire facade construction is to use a simple curtain walling system where possible, with bespoke inserts to achieve the non standard details. The bonded glazed units are tied back to the main super structure. The mesh is bracketed off the curtain walling to meet the same plain as the bonded units and to achieve the flush outer layer. This principle continues around the entire facade front and rear.

In order to maintain a reading of the building as a whole the colour palette is carefully calibrated to respond to the masonry tones from grey concrete mortar to mid brown bricks. The reflectance of the materials increases as you ascend to sky and the textural quality of each material selected is emphasised by various means.

A champagne coloured anodised metal panel is used for the mesh on the upper storeys. This is perforated with small holes achieving 40% free air flow and is also calculated to appear almost invisible from the inside to retain views across London. A waved profile adds another layer of light quality maximising incident sun throughout the day. The anodised surface is iridescent in sunlight.

The transition from the mesh to the glazed bonded panel is carefully managed by introducing a matching fritt within the double glazed bonded unit. This softens the overall appearance of the glass which would normally be a contrasting frame and fritt colour. Felt curtains have been introduced to the larger windows fronting onto the street to extend the waved mesh detail across the entire facade. The brick has been lightly cleaned and repointed where spalling with the intention to retain the relic with minimal surface alteration. All concrete lintels and cills and window frames are painted a matt colour to match the brickwork attempting to simplify the reading of the retained element. At ground level the shop front is framed in concrete supporting the building mass above. The glass panels within being as large as is permissible with the constraints of the tight street and working zone. Again a fritt has been selected to match the concrete colour to soften the junctions.

An installation by Tim Etchells was exhibited for 6 weeks from September to October 2013. The neon piece entitled 'shouting your demands from the rooftops should be considered a last resort' was selected for its obvious irony in the context of imminent marketing of the building, but also to demonstrate the opportunity to use the high level glazed pods for exhibition.