Glazed clay block screen : Netherlands Bank – Durban 1965_____________________________________________________
|In:||Architecture SA May/June |
Netherlands Bank, Durban
Norman Eaton was briefed for the design of a bank of outstanding design, with a ground floor space uninterrupted by columns. The result was an architectural gem with one of the first hanging structures in South Africa. The two intermediate floors were suspended by steel rods from deep reinforced concrete roof beams which also accommodate the soil for the roof garden. The rods were encased with asbestos-cement fire protection insulation and covered with stainless steel sheet to a total of 50 mm in diameter. To compensate for deflection after the shutter supports were removed, the roof beams and perimeter columns were cast with a camber of 10 mm.
The more striking element of the building is its sheer external sun screen. It is constructed of hollow clay blocks made by Briti in Alberton, very similar to their standard spacer blocks for rc floor construction, glazed on the outside by Dykor in Pretoria, and railed to Durban for erection.
The screen was erected from the bottom up, the first course being bedded in plaster of paris on correctly levelled and positioned scaffolding.
The screen is supported from projecting floor slabs by 25x3mm vertical steel hangers in every second soldier block. In addition each horizontal course is reinforced with two 6 mm diameter steel rods, welded to the hangers. The hangers and rods were welded together in lifts of about 900 mm as the work proceeded, to enable the clay blocks to be stringed over them. The blocks were then filled with mortar and tamped to ensure positive coverage of the steel before the next block was put in place.
Inadequate coverage in some places led to the rusting of steel reinforcement in Durban's corrosive atmosphere, resulting in spalling of some blocks. Remedial work was done after five years. The screen is in excellent condition.
Architect: Norman Eaton