In the extensive re‐organisation of the Farsons Brewery Campus to make way for the Trident Park complex, all of the corporate offices were consolidated and transferred to one building. The existing single storey office was the site chosen for this but it was located above a warehouse, and it was a stone masonry structure roofed over by a concrete slab of limited load bearing capacity. The brief called for an overlying two‐storey extension to be able to contain all the offices.
The problem of the existing structure was a constraint that became the primary design philosophy; a lightweight structure in steelwork was chosen with external cladding for the envelope. Internally there are castellated beams allowing the passage of the integrated services. This industrial aesthetic, contrasting with the limestone of the lower floor, reflects the language of the Brewery.
The structural grid of the existing office was primarily dictated by the warehouse underneath. In fact the plan is rather deep for day‐lit offices; therefore introducing daylight into the interior was vital. Neither the warehouse and nor the offices could be interrupted; consequently the roof slab could not be pierced to create the pit for a new lift, and the slab could not be strengthened to carry additional loading. The lift was located outside the existing envelope, and the interior was required to have a visual vertical movement to reflect the stateliness of the original entrance, staircase, and boardroom in the 1950s Brewery. Using a different idiom the challenge was to replicate the grandeur using contemporary industrial materials.
The concept finally developed into two flights of oval winding stairs, rising within a top‐lit atrium, making the climb as comfortable and well‐lit as possible, but also eye‐catching and uplifting. The idea for the oval-shaped staircase, repeated on two floors, evolved from the original idea for a continuous loop, based on the desire to consider the staircase as a spiral flow up the atrium. The space available was defined by the grid of the existing reinforced concrete structure and the cantilevered structure of the stairs generated rather high stresses in the existing loadbearing concrete. The structural solution provided cable supports for the stairs as an object caught in a spider’s web, relying on the existing concrete beams and the steel beams of the extension.
