Opportunities for building exciting facades in clay have never been better than they are today and the new Victoria Gate Arcade in Leeds has set a new standard for innovative building with brick. Acme Architect’s outstanding design used a blend of light and dark red Ketley brick slips in conjunction with bespoke special bricks to create precast brick faced panels which have been arranged in a complex geometry with steps and pleats to form an innovative 3 dimensional masonry façade.
It became clear early on in the project that, as many bricks would have 5 exposed faces, choosing the right one would be key to the project’s success. Dimensional stability, an absence of inferior faces, low water absorption and high frost resistance, high strength and the right finish to complement the predominantly Victorian local vernacular were all key requirements.
Luke Smerdon-White, Technical Director at Thorp Precast, who supplied the panels, explained that "a class A brick was really the only option for this project. The projecting headers and geometric shapes within the design required sharp edges and straight lines. On the exposed surface of the projecting headers, water can be held and the brick therefore needed to be of a high specification with low water absorption. In our rigorous testing, Ketley performed the best". Thorp Precast supplied the brick faced façade on the basis of a full CDP design, manufacture and installation basis.
They undertook comprehensive accelerated freeze thaw testing on the Ketley brick and the methods of embedment within the precast panel given the severe exposure conditions, with positive results, prior to full scale manufacture of the panels. Ketley’s class A bricks and brick slips are both made from Etruria Marl clay, at the same Works in Brierley Hill in the West Midlands which began making clay products back in 1805. Their brick slips are extruded, having only 30% of the embodied carbon of a cut brick, making them a highly cost effective and sustainable choice for construction. All Ketley’s products deliver the same technical characteristics of very low water absorption, very high strength and unrivalled frost resistance, all key criteria for this project.
The colour of the brick was also very important both to Hammerson, developers of this prestigious retail arcade and to the planners Leeds City Council. Some variation within the red was required and Ketley supplied both light and dark Staffordshire red products which were mixed to good effect before being assembled into the panels. To eliminate the costs of cutting the bricks, Thorp and Ketley designed a bespoke die to produce "snap" headers that could be broken in 2 by hand without the need for cutting. These bricks once they had been “snapped” had a special perforation that allowed the concrete to get a positive key to the brick. Each brick and brick slip was carefully placed face down into specially designed moulds containing a negative of the pleated panel pattern and the concrete was then poured on top to a depth of 150-400mm. Once the concrete had hardened, the panels were removed from the moulds, meticulously cleaned and the bricks pointed before they were delivered to site for assembly.
With almost 550 panels and a building of this scale and complexity, 3D software was used to plot and place every individual brick (there were approx. 360,000 used in total). The project is a fantastic example of modern construction methods using traditional brick. The use of bespoke special snap headers and extruded bricks slips eliminated the cost of cutting and minimised the embodied carbon in the building. Offsite construction allowed Thorp to control the quality of the finish of every panel by completing it at their workshop and delivering it ready to be fixed onsite to the steel frame of the development. The finished project has become the city of Leeds latest landmark and its complex, innovative design of pleated brickwork sits harmoniously with the richly textured historic brick of the surrounding architecture.