40 Holborn Viaduct

40 Holborn Viaduct - ‘A Green Gateway to The City’ This is not a new building. We are working with The City to deliver an exemplary sustainable retrofit, retaining approximately 70% of the original embodied Carbon and delivering 17, 050 m2 of fully decarbonised, Class A contemporary workspace. Three new extension levels have been added to the eight-story office building with new balcony extensions to the southwest elevation. Our proposal responds to its prominent triangular site by creating a green gateway building for the City of London. It is a modern version of the historic gateways into Roman London. The main road into London from the west of England bifurcates at this point, north to the new The City of London cultural quarter including the new London Museum and Smithfield Market and south over Holborn Viaduct, a marvel of Victorian 19th Century engineering, to St Pauls Cathedral and the historic City Mile. The area is changing and becoming an attractive, vibrant hub of commerce and culture in the City of London, anchoring the convergence of four City Business Improvement Districts (BIDS). The heavily defensive stone envelope of the existing building will be replaced by an open animated façades with balconies and seasonally varied planting onto Holborn Circus and Holborn Viaduct. The mined façade stone is recycled as terrazzo in the proposals. A transparent base opens onto social activities within the building (café, reception, amenities, auditorium) animating the public realm. Well-being is prioritised with seasonally changing planting to all areas including terraces, a pergola, a sky lobby, a green roof and the publicly accessible pocket garden. New amenities include shared workspaces, terraces to every floor, a panoramic sky lobby and activity terrace, an events space, cafes, fitness and wellness suites and, best in class end of journey facilities for cyclists and other users. The pocket garden creates an animated buffer and spill out area for a ground floor café with spaces for public seating and assembly. Planting provides colour, interest, and shade and a 100% increase in Urban Greening (diversity) for the site. A rain garden helps control water run off rates. Grey water is used for irrigating the ribbon planting. The main body of the building is characterised by terraces and balconies with planted ribbons faced with innovatively crafted black vitreous enamel. The ribbons run all round the building establishing a unified identity from all aspects. Indents to the planter ribbons reflect where structural columns or hangers connect, providing subtle variations reflecting context, aspect, and use. A pergola creates a double height cornice structure with horizontal blossom enhancing buildings gateway appearance. Three new extension levels create stepped terraces, a sky lobby and a sky terrace with panoramic views for use by tenants. The roof provides plant areas and a maintenance access BMU serving facades and planters. This proposal will deliver a sensitive repositioning, a Carbon reset of a failing asset, so critical for this special location.