page_title: The Crystal Palace
section_title: Design
hierarchical_section_title: The Crystal Palace / Original Hyde Park building / Design
context_page_description: The Crystal Palace was a cast iron and plate glass structure originally built in Hyde Park, London, to house the Great Exhibition of 1851. The exhibition took place from 1 May to 15 October 1851, and more than 14,000 exhibitors from around the world gathered in its 990,000 square feet exhibition space to display examples of technology developed in the Industrial Revolution. Designed by Joseph Paxton, the Great Exhibition building was 1,851 feet long, with an interior height of 128 feet. It was three times the size of St Paul's Cathedral.
  The introduction of the sheet glass method into Britain by Chance Brothers in 1832 made possible the production of large sheets of cheap but strong glass, and its use in the Crystal Palace created a structure with the greatest area of glass ever seen in a building. It astonished visitors with its clear walls and ceilings that did not require interior lights.
  It has been suggested that the name of the building resulted from a piece penned by the playwright Douglas Jerrold, who in July 1850 wrote in the satirical magazine Punch about the forthcoming Great Exhibition, referring to a "palace of very crystal".
context_section_description: Paxton's modular, hierarchical design reflected his practical brilliance as a designer and problem-solver. It incorporated many breakthroughs, offered practical advantages that no conventional building could match and, above all, embodied the spirit of British innovation and industrial might that the Great Exhibition was intended to celebrate.
  The geometry of the Crystal Palace was a classic example of the concept of form following manufacturer's limitations: the shape and size of the whole building was directly based around the size of the panes of glass made by the supplier, Chance Brothers of Smethwick. These were the largest available at the time, measuring 10 inches (25 cm) wide by 49 inches (120 cm) long. Because the entire building was scaled around those dimensions, it meant that nearly the whole outer surface could be glazed using millions of identical panes, thereby drastically reducing both their production cost and the time needed to install them.
  The original Hyde Park building was essentially a vast, flat-roofed rectangular hall. A huge open gallery ran along the main axis, with wings extending down either side. The main exhibition space was two stories high, with the upper floor stepped in from the boundary. Most of the building had a flat-profile roof, except for the central transept, which was covered by a 72-foot-wide (22 m) barrel-vaulted roof that stood 168 feet (51 m) high at the top of the arch. Both the flat-profile sections and the arched transept roof were constructed using the key element of Paxton's design: his patented ridge-and-furrow roofing system, which had first seen use at Chatsworth. The basic roofing unit, in essence, took the form of a long triangular prism, which made it both extremely light and very strong, and meant it could be built with the minimum amount of materials.
  Paxton set the dimensions of this prism by using the length of single pane of glass (49 inches (120 cm)) as the hypotenuse of a right-angled triangle, thereby creating a triangle with a length-to-height ratio of 2.5:1, whose base (adjacent side) was 4 feet (1.2 m) long. By mirroring this triangle he obtained the 8-foot-wide (2.4 m) gables that formed the vertical faces at either end of the prism, each of which was 24 feet (7.3 m) long. With this arrangement, Paxton could glaze the entire roof surface with identical panes that did not need to be trimmed. Paxton placed three of these 8 feet (2.4 m) by 24 feet (7.3 m) roof units side-by-side, horizontally supported by a grid of cast iron beams, which was held up on slim cast iron pillars. The resulting cube, with a floor area of 24 feet (7.3 m) by 24 feet (7.3 m), formed the basic structural module of the building.
  By multiplying these modules into a grid, the structure could be extended virtually infinitely. In its original form, the ground level of the Crystal Palace (in plan) measured 1,848 feet (563 m) by 456 feet (139 m), which equates to a grid 77 modules long by 19 modules wide. Because each module was self-supporting, Paxton was able to leave out modules in some areas, creating larger square or rectangular spaces within the building to accommodate larger exhibits. On the lower level, these larger spaces were covered by the floor above, and on the upper level by longer spans of roofing, but the dimensions of these larger spaces were always multiples of the basic 24 feet (7.3 m) by 24 feet (7.3 m) grid unit. The modules were also strong enough to be stacked vertically, enabling Paxton to add an upper floor that nearly doubled the amount of available exhibition space. Paxton also used longer trellis girders to create a clear span for the roof of the immense central gallery, which was 72 feet (22 m) wide and 1,800 feet (550 m) long.
  Paxton's roofing system incorporated his elegant solution to the problem of draining the building's vast roof area. Like the Chatsworth Lily House (but unlike its later incarnation at Sydenham) most of the roof of the original Hyde Park structure had a horizontal profile, so heavy rain posed a potentially serious safety hazard. Because
caption: Plan of the Crystal Palace
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