NZASM Building Materials
The erection of the NZASM buildings was the largest single exercise in prefabricated architecture, bar the structures of the goldmines on the Witwatersrand, at that time.
For the construction of its buildings other structures the NZASM engineers preferred natural stone like sandstone, ironstone (dolerite) or hornsrone ('blouklip') . These building materials were readily available at many places and obtainable free of charge. They possessed great strength and beauty, and were very suitable for use in the designs chosen. For these reasons most buildings of the Eastern and South-Eastern lines consist of sandstone or other natural stone.
Brick was used in places where natural building stone was unobtainable locally, or where brick was cheaper and more readily available, as was the case with most of the buildings of the South-Western (Klerksdorp) Line.
NZASM stone masonry and brickwork were generally of a high quality because of the strict regulations specifying the laying of foundations, the shapes and sizes of stone blocks and bricks, the manner in which courses were to be laid, the width and finish of mortar bonds and the composition of mortar.
On the Rand Tram and the Southern Line many buildings of corrugated iron were also constructed by the NZASM, especially station buildings. This blended well on the Rand Tram with the corrugated iron settlements of the gold-mines in its proximity. Corrugated iron was used throughout on all the lines for the plain industrial structures such as sheds, locomotive roundhouses and workshops.
Most of the ironwork of buildings, and nearly all requirements for floorboards, frames, ceilings, doors, window sashes and panes, fixtures, paint, cement and roof timbers were imported from the Netherlands, Belgium and Germany.
(De Jong et al, 1988: 87)