Consultant, Harris & Sutherland

Masonry has changed markedly in the last 100 years both in its use and in its form. The question is whether all the changes have been for the good or whether we have taken some wrong turnings. Structural framing has usurped some of masonry’s traditional load-bearing function but even with frames masonry is still widely used for cladding. The thickness of structural masonry walls has been much reduced following developments in analysis, while the cavity wall, mostly with the outer leaf unloaded, has become all but universal. Today materials are being mixed and problems of compatibility and movement abound, leading to many mastic joints and increasingly complex means of support. The paper discusses the gains and losses and concludes that the cavity wall in its present form it a mixed blessing, Its popularity is by no means universal in other countries. There is clearly a case for considering a return to solid walls in some circumstances and for revising our treatment of the cavity wait in others. On a broad level the debate may come down to a philosophy of planned restraint instead of our present one of permitted movement.