Mountford Pigott were instructed by Big Yellow Self Storage to design a landmark storage building adjacent the elevated section of the M4. They wanted to minimise the area of site used so they could maximise the potential in the residual site for future development. The final design consists of a sculptural form with curved elevations responding to the curve of the M4, with differing rain-skin panels . A rectilinear glass box at 4th and 5th floors penetrates this pure form presenting the inner workings of the building to passers-by on the M4. Signage is integrated into the buildings skin rather than simply applied to the elevations. The building has a gross storage area of 115,000ft² over a part 2 and part 8 storey structure. The service yard, large enough to turn an HGV, is set underneath the taller element. To achieve this the upper 6 floors are suspended from large trusses in the roof area. Detailed Planning was achieved in April 2010, works started on site in April 2011 following demolition of the former Sotheby's Depository on the site. Practical Completion was achieved by McLaren Construction in February 2012.