Bridgewater Place shimmers on the Leeds skyline. The 32 storey tower, clad with anodised aluminium panels presented a challenge for cladding contractor EDM Spanwall.
A stiffening structure had to be attached to the back of each of the panels so they retained their shape.
But EDM was concerned that traditional, mechanical fixing methods would result in 'readthrough' and be visible from the front of the panel.
'With rivets you can get dimples at the edges, if not a rivet head, ' says EDM design manager Paul Greene. 'And welding can cause a panel to deflect or colour'.
To overcome this, the company turned to 3M, which used its extensive expertise in adhesives to help find the perfect solution. 3M is probably better known for its Scotch tape and Post-it notes. But in Leeds, the answer it came up with was one of its range of VHB acrylic foam tapes.
The tape bonds metals, plastics and glass, eliminating the need for drilling, and fasteners.
VHB tape is made with acrylic foam, which is viscoelastic in nature enabling it to absorb energy.
This enables the interface between panel and stiffening structure to withstand stresses caused by wind, vibration and thermal expansion. It provides a long-lasting bond which is claimed to be capable of withstanding the rigours of Yorkshire winters, as well as its summers.
Such tiny details had an important role to play when delivering the vision behind the project, says Michael Gardner, project leader at architect Aedas.
'The building is a mixeduse project in which all the elements are fully integrated.
It was important that all the functions read together as one building.
'The ffices in the lower portion, however, need a stronger, more secure feel, so architectural precast concrete was used. The residential tower needed a lighter fresher feel and hence here we opted for natural anodised aluminium to compliment the crisp even bands of windows and cladding.
Ensuring the panels were of the highest quality, smooth and uniform was very important.' says Gardner: 'We are very pleased with the appearance of the panels.' As well as the aesthetic advantage of preventing readthrough, welding and riveting add cost and complexity to the fabrication process as they require extra preparative steps.
Adhesive tape is more easily and quickly applied without the need for mechanical abrasion or clamping. These process savings quickly add up as EDM Spanwall has had to secure backing to more than 2,400 panels in order to cover 2,900m 2 of the 137m tall building.
'The adhesive solution offered substantial savings in materials and labour by reducing the need for any mechanical abrasion of the surfaces prior to bonding, ' says Greene.
'The ability to reduce the number of welded and riveted connections reduces the possibility of stress points which can result in read through and spoil the over all aesthetic of the system and the building façade.
'External orks Bridgewater place are now almost complete, allowing handover for internal space fit out in November.