The architectural centrepiece of the new £240million Lexicon Centre in Bracknell, UK, is its stunning aluminium cladding. Here’s how precision shot peening from Wheelabrator delivered the signature look.
Redeveloping the centre of a town is no mean feat – especially when the brief is to create a brand-new 580,000 sq ft retail and leisure space.
However, just 10 miles from Reading, Windsor and Maidenhead, is the post-war new town of Bracknell in Berkshire. It was prime for redevelopment, so the local council seized the opportunity to start again and create a thriving centre with a social, communal and cultural heart.
The biggest single element of the plan was the £240 million Lexicon retail and leisure complex. Promising a mix of more than 70 shops, restaurants and entertainment venues, it quickly became one of the UK’s biggest redevelopments.
The aim was to create a new focal point for Bracknell that captured the visionary aspirations of the project with flowing, green, open space and an eye-catching contemporary aesthetic.
Architects BDP utilised a palette of warm materials including brick, timber, and bold perforated shot peen finished aluminium, with concepts for elegant street covers and canopies.
Aerospace precision meets architectural cladding
Integral to the final designs of BDP was an eye-catching matt aluminium façade for the prestigious Fenwick department store.
Mace, the lead contractor on the project, appointed Prater to design, supply & install the external envelope. They worked closely with Prater’s cladding designer, and Bailey (fabricating, design and procurement) to develop an intricate design with a striking pattern of circles that could be lit from behind.
A major specification challenge was born of the desire to achieve an impeccable finish and super-high performance from 5mm aluminium. Further demands were to minimise corrosion, guarantee longevity and provide a suitable surface for anodization. Add to the mix the need to create 2,200 panels in 21 different designs – all of which needed to be precisely uniform in colour and finish – and the scale of the challenge was clear.
With such rigorous criteria, it is perhaps no surprise that the cladding designers had to look outside the construction industry for a solution.
Peter Woods, production manager, at Bailey said: “The aluminium cladding on the exterior of the Fenwick department store was essentially the cherry on the cake. The panels were vital to the architectural aesthetic, and the look had to be right.
“To provide a controlled, even-textured shot peened finish to the panels for the statement façade, aerospace metallic know-how was needed to ensure that the correct shade, longevity and performance credentials were achieved.”
Bailey appointed Wheelabrator Impact Finishers to lend their specialist expertise in high-spec peening processes for aerospace and automotive.
A surface forged by thousands of tiny impacts
Mimicking the centuries-old method of working metals with a hammer to compress the surface, shot peening hardens a metal product by bombarding it with steel, glass or ceramic beads.
Thousands of tiny impacts at a time change the performance properties. Engineered materials become stronger, more damage proof and corrosion resilient resulting in lower maintenance and longer life.
Peening also has many visual benefits. It creates a subtle, uniform finish with a distinctive, dimpled texture, and enables reflectivity to be reduced – all of which were required for the external envelope of the Fenwick department store.
Chris Pallot, Business Development Manager for Wheelabrator commented: “Given the bold aspirations of the Lexicon project and the desire to create a lasting legacy, the aluminium needed to be optimised to take pride of place.
“With façades for town centre stores like Fenwick, durability and straightforward maintenance are key. Shot peening achieves a finish that will stand the test of time - it’s built for the long haul. Maintenance is negligible, and panels can simply be cleaned with soap and water.
“The team at Wheelabrator met with Bailey early on to advise on specification and treatment for this application to marry the ambitious aesthetic vision with what we knew to be technically possible.
“With such a large volume of panels – 2,200 spanning 21 different designs – it is very important that the shot peened finish is even and consistent. Any patchy areas would catch the eye immediately.”
Perfecting the panels
To ensure the façade delivered visual impact while retaining its strength and performance, Wheelabrator worked closely with Bailey. The team drew on the experience of finishing dozens of prestige architectural projects and harnessed the possibilities offered by cutting-edge, automated plant technology to apply a perfect shot peened surface to each panel.
Given the uniformity of finish required, Wheelabrator chose to use completely non-ferrous shot to deliver an even, non-directional textured finish with a consistent depth to each panel, with zero risk of ferrous contamination.
Over three months, Wheelabrator Impact Finishers, the shot peening sub-contract services divison of Wheelabrator, shot peened 2,200 panels equating to 2,000m sq of 5mm aluminium.
With the Lexicon now open to the public, the panels provide an eye-catching exterior for the Fenwick store.
Peter Woods, production manager at Bailey, said: “The collaborative approach, in-depth technical knowledge and quality control processes from Wheelabrator helped us work to tight timescales and deliver the high standard required for one of our most important clients.
“Most importantly of all – the results look stunning and we’re delighted to see the Fenwick store open to the public and impressing all that pass with its stunning façade.”
For queries on architectural shot peening or advice on specifying it, please contact Chris Pallot at Wheelabrator Impact Finishers, on 01753 215676 or email.