Curtain walling—glazing systems
Nineteenth-century Victorian glasshouses gave many opportunities for the development of dry assembly systems of glass and metal (Fig. 6.2). Many of these are shown by Hix (1995) in his excellent historical study of glasshouse construction. Joseph Paxton’s Crystal Palace had wooden glazing bars made on site by sophisticated milling machines, but by the time it was moved to Sydenham it was largely rebuilt using metal
glazing bars and a puttyless glazing system, the recognized advantage of which was illustrated by the abundance of patents taken out at that time (hence ‘patent glazing’). Sections of the nineteenth-century patent glazing bars are shown in Guedes (1979). It was the necessity to provide good natural lighting in factories, using north light roof construction in the 1920s and 1930s, that really promoted the commercial development of the large number of types of patent glazing sections used today (Fig. 6.3). Modern patent glazing systems for both inclined and vertical applications were shown in Patent Glazing Conference (1980); however, more recently this type of glazing support has fallen out of favour, mainly because of inherent difficulties with thermal breaks and the availability of more sophisticated forms of curtain walling.