The Zig Zag Building is part of a development area in London’s Victoria Street designed by Lynch Architects and developer Land Securities bringing civic qualities to this area and creating a lively town center. The name Zig Zag Building refers to the irregular shape of the building with its multiple recesses. Vertical fins are echoing the verticals of Westminister Cathedral and City Hall. These façades are acting as intermediate spaces with openable windows, balconies, roof terraces and welcoming areas on the ground floor.
Horizontal as well as vertical sheet metal fins give the façade is specific structure. The vertical fins support a curtain-type sun protection with stone print PVB interlayer. The residential and office building with its recesses and terrasses is harmoniously merging with the surrounding stone buildings. Each façade element is unique – this is also due to the varying dimensions between axes of the façade units which have been fabriquated by the German curtain wall manufacturer Gartner.
Façades speaking to the city
The 80 m long and 30 m wide development in Victoria Street, near Buckingham Palace, consists of a residential building and an office building. To the East, the building reaches it highest point at 52 metres which is slightly underneath the neighbouring Westminster City Hall.
The 13-storey building is a mixed use development with offices above two floors of retail units. Architect Patrick Lynch wanted to realize an urban office design. „It’s the façade that speaks to the city,“ says Lynch. So the façade should act as a threshold between the world of its occupants and the city beyond. Users should be able to occupy, relate to and interact with the public/surroundings by opening windows or stepping on to terraces. Therefore, the façades should act as intermediate spaces rather than opaque or reflective boundary planes. Lynch is inspired by Renaissance Florence: „They have a base and a top, and there´s a delicious pleasure in walking past these buildings because their lobbies are like urban rooms.“ At low level, the Zig Zag Building has active retail frontages, stepped in section.
Abundance of natural light and openable windows
The building offers 188,700 sq. ft. commercial office space with private terraces on 7 floors and also a total of 187 cycle parking. The building is characterized by flexible floor plates, an abundance of natural light, and enviable sustainability credentials. It expands the public space by throughfares, gardens, restaurants and retail. Most of the shops, office and residential areas were let or occupied in 2015, including a restaurant of the celebrity chef and restaurateur Jamie Oliver. In November 2015, Deutsche Bank Asset Management and Private Wealth Management relocated to Zig Zag Building.
Mechanical ventilation is not needed thanks to a façade with careful sun-shading and openable windows together with cooled ceilings.
Furthermore, the building is designed to last more than a century and has been awarded the prestigious BREEAM “Excellent” certificate. The building is also winner of the „Commercial Development“ of the Year at the 2016 PROPS awards in May 2016.
Low-iron glazing with printed PVB interlayer and onyx pattern
The architectural design is dominated by curtain-type horizontal and vertical metal sheet fins which give structure to the building and are aligned to an internal grid of 1,5 m distance. As the building depth and the distances between the building axes are diminishing from the ground floor to the upper floors, the distance to the front edge diminishes as well making the building look narrower as it rises.
At the upper part of the vertical fin interspace, there are glass panes of 1,100 mm height each, protecting the tenants from direct solar radiation. Especially during hours of high sun elevation at the south side of the building, the fins provide good shading to the rooms. Low-iron glasses which allow for good colour reproduction, have been provided with a printed PVB interlayer resembling onyx stones. A total of 23 different onyx patterns have been fabricated by use of special printing technology and installed into their individual position at the building. The laminated safety glass panes with printed interlayer were thus given their unique aspect and create irregular patterns. As compared to the printed glazing, glasses with printed interlayer also allow for more complex and multi-coloured designs.
Unique façades with different axial dimensions
Most of the elements of the façade with its total volume of 11.500 m² are 3,85 m high and weigh approx. 800 kg. The planning grid is approx 3 m. Due to the irregular floor plan of the building and the different sizes of the fins there are numerous types of different axial dimensions. Into each façade unit, Gartner has installed individually operable window leaves with Juliet balconies. Die pivot windows can be opened mechanically in positions from 15 up to 90 degrees. Here, tenants can choose whether they prefer to only open the upper part or the full height of the window down to the floor.
Mullion-transom façades in three different designs
Other areas were mostly closed by 1,200 sqm large mullion-transom façades in three different designs. Recesses, ceilings, terraces or soffits are continuously subdividing these areas. The stainless steel mullions of the 8 m high entrance façade area are positioned at the outside instead of the inside, this area has, therefore, been glazed on the inside. The ground and first floor on the north side were clad with louvres on the steel tubes of a mullion-transom façade. The major part of the façade is bronze anodised. On the ground and first floor, the façades are clad vertically with brushed stainless steel panels, and with mirror finish stainless steel panels on the soffits.
Double insulating glass with laminated safety glass
Office areas are glazed with double insulating glass with laminated safety gass VSG, inside as well as outside (outside with heat strengthened TVG) with a solar control coating Sunguard HS SN 70/37 HT. The shops in the lower two floors are also provided with double glazing, with laminated safety glass VSG (outside with heat strengthened TVG) inside as well as outside, and with solar control coating Sunguard HS SN 62/34. In addition to the façades, Gartner supplied a canopy, door systems with storey-high sliding doors, revolving doors and pivot doors, balustrades in stainless steel, aluminium and glass, the sheet cladding of the façade, louvres for the roof area, and the cladding of the roof structures with louvres and glass.