Assessment of an open jointed limestone veneer cladding system for use in the local construction industry

Abstract

Beginning with the Industrial Revolution and rapidly increasing following World War II, building envelopes changed dramatically. Exterior wall construction that had previously consisted of thick mass masonry evolved into contemporary curtain wall systems. As curtain wall systems evolved, the economics of reducing the thickness and weight of curtain wall components became more important therefore the industry looked to produce new materials but at the same time keeping the aesthetically pleasing appearance of natural stone. The use of thin stone veneers on buildings in these last years is not associated with increased knowledge of stone material properties. Rather the reduction in thickness is attributable to advancements in fabrication technology, economy in construction and the rational approach to design of veneer systems. Physical and Mechanical testing was conducted on composite Stone faced aluminium panels filled with a medium density polyurethane foam. Testing was conducted on specimens measuring 600 by 600 mm, to test certain strength, durability and performance aspects when used as exterior cladding panels in an open jointed curtain wall system. The stone facing used was Lower globigerina limestone. The results strongly suggest that though the thickness of the actual stone is reduced when compared to previous researches done locally on stone cladding panels, the panel as a whole performs much better and safer when subjected to impact and static load tests. This further highlights the fact that the performance of such panels is dominated by the composite aluminium section. The stone portion is essentially a thin veneer that provides very little structural strength. When subjected to thermal and moisture cycles the panels also performed quite well with no visible cracking in the stone facing. This dissertation will present and discuss this fairly new technology of using stone veneers as facings on cladding panels together with its feasibility and application in the local context. Results of the testing is also presented and analysed.