The selective use of slate in vernacular farm buildings and structures north of the Vaal River

Abstract

Slate and shale are not usually considered as building stone for the construction of entire buildings in the vernacular farm architecture of the area north of the Vaal River (historically known as the Transvaal). Sandstone and granite as principal building stone types were more common. Slate and shale are two different stone types but due to their similar layered structure they are often used together in the construction of the same wall. Current research has revealed that slate and shale did play a significant but selective role in vernacular building technology in the region. Slate was used for finishing and solving specific problems in folk building technology. One of the reasons why these stone types were less popular as building materials is the isolated occurrences of outcrops in the region. Sandstone and granite are more common and readily available. The few buildings constructed with slate and shale had a unique character reflected in the wall texture when the stone is laid flat. Because the stone is released from its rock bed in thin plates with an almost completely flat surface on both sides, it is usually laid flat and needs little mortar to secure a stable wall.This paper introduces rather than analyses the use of these materials in the vernacular architecture of the former Transvaal region.

Die gebruik van leiklip en skalie as konstruksiemateriaal vir geboue en strukture op plase in die ou Transvaal is minder algemeen as die gebruik van ander tipes klip soos sandsteen en graniet. Skalie en leiklip is twee verskillende gesteentes, maar as gevolg van hulle ooreenstemmende gelaagdheid en breekwyse kom beide materiale dikwels saam in dieselfde muur voor. Een van die redes waarom die materiale nie so algemeen gebruik word nie, is moontlik omdat dit minder algemeen as sandsteen en graniet in ‘n streek voorkom. Op die plase waar dit as konstruksiemateriaal gebruik was, het dit gelei tot die skep van besondere geboue. Dit is deels as gevolg van die karakter van die klip wat as konstruksiemateriaal slegs op een manier gebruik kan word. As gevolg van die dun lae waarin dit ontgin word, word dit plat gelê en is min bindmateriaal nodig vir die konstruksie van mure. Hierdie artikel is ‘n inleiding eerder as ‘n volledige analise van die voorkoms en gebruik van hierdie materiale in die volksboukuns van die destydse Transvaal.