In the north Barbican area, the layout of terrace blocks in the 1959 Scheme was completely different from what was ultimately built. In the south Barbican, the most striking difference on the plans is that the bridge across the lake was to run diagonally to Fore Street with no “Gilbert House” above it. (An earlier version, mercifully dropped, had a road in a totally enclosed box running right across the estate in a diagonal line from Golden Lane area to Fore Street.) The external appearance of the buildings was also to be very different. The walls of the terrace blocks were to be faced with white marble blocks with riven faces. The columns on the podium supporting the buildings were to be constructed of concrete, compounded of white spar aggregate in a coloured cement matrix, then polished to a fine surface. A similar material was to be used for the external structural lattice of the towers. Subsequently the architects changed their design of the exterior of the buildings from polished concrete or ceramic material to rough concrete, to meet the City’s concerns about the cost of the proposed materials and building methods.
The Barbican estate, as eventually built, employed concrete in a much more monumental way than was envisaged in the comparatively delicate designs in the 1959 Report. This was made possible by using in situ reinforced concrete as the method of construction. The opportunity was provided by the engineers’ adoption of deep beams spanning between wide-spaced cross-walls, which Chamberlin Powell & Bon exploited as a feature particularly in the more exaggerated forms of the external balconies.
There were other changes before the final look was achieved. The design of the towers underwent changes after 1959. An irregular roof line, triangular projecting balconies, and vertical structural members were introduced to the design.
Their initial designs had also played heavily on the association of “barbican” with a walled fortification, and designs had included moats, turrets and arrow slits. As plans progressed, these references were toned down, but you can still see distinct arrow slits in the walls opposite Barbican Station, and the moat motif remains in the water lapping Brandon Mews and behind Wallside.