Despite its, as yet, incomplete façade - the dramatic rooftop enclosure arrives this summer - One Blackfriars is well on its way to being a beautiful addition to the London skyline. But its apparently simple façade is the result of much consideration. Hundreds of thousands of hours have been spent honing the concept, rationalising the geometry and crafting the detail and specification of the building’s external appearance.
The form of the tower is determined by a response to its location in the city. To the passer by it is a singular marker of a particular place to be read as a complete entity. The reality is that it is made up of 274 individual homes which create contradictory demands between its inside and outside. This dilemma is solved, conceptually, by considering the tower as a 'building within a building', with two distinct and independent façades. An inner skin defines the individual homes responding to the specific requirements of the bedrooms, living rooms and the thermal performance. The smooth single glazed outer skin encapsulates the form, reinforcing its shape with tapering lines. The outer skin speaks to the city by emphasising the whole, whilst the inner skin speaks to each home by addressing the individual. Connecting the two skins are high specification winter gardens; enclosed balconies that circle the entire building.
5764 single glazed panels are set within a fanning grid that follows the elegant lines of the building, so that when you look up it feels immediately visually natural. The geometry was carefully considered resulting in a building that is curvaceous and unified despite 70% of the glass panels actually being flat. Of the remaining 30% curved panels, 98 are double curved, that is, bent in both plan and section.
The façade detailing is subtly effective. Electrically operated glass louvres help maintain natural ventilation inside the winter gardens and the apartments without detracting from the building’s smooth surface. They also make the building watertight to a wind pressure of 2000Pa, four times that of domestic windows. Positioning the louvres in parallel lines running along the fanning grid of the glass panels also creates a subtle order to the building’s outer skin, much like a pinstripe on a suit. Air intake and extract grilles are designed discreetly alongside external lighting strips, and integrated into the transom. The only disruption to the façade’s smooth surface are two 40mm protruding aluminium fins on either side of the pinstripes.
To achieve the right balance of clean colour, reflectance and transparency, we exhaustively tested glass samples. Using low iron glass with two solar coatings together with metallic glass coloured panels placed on the outside of the inner skin within the winter gardens, we have created a unique and constantly changing façade, offering a rich depth and a shimmering reflection of the city, the sky and the river.