Palm House (1844-18448)
The incredible lightness of the structure and the purity of its shape make the Palm House one of the most iconic buildings in London. The character of its architecture is deeply dependent on its content: the majestic exotic palms coming from all over the world. The architecture seems to be made up of the tropical forest inside and, once we are in, the glass and iron of the envelope somehow disappear, or, better, remain just for marking the preciousness of such a space, which recreates the conditions of an exterior, inside an artificial space. This elegant greenhouse was commissioned by the director of Kew, Sir William Hooker, in 1844, few years later The Royal Botanic Garden of Kew became a national institution. The design is the result of a collaboration between the engineer Richard Turner, who had a considerable experience in iron structures and curvilinear glass, and the architect Decimus Burton, who was part of the Royal Botanic Society. The conversion from a royal garden to public garden is a relevant aspect of the meaning of the Palm House’s architecture. The glazed surfaces and the function of the greenhouse, in fact, initially, remind to the gentle architecture of the orangeries of the previous centuries, symbol of the old aristocracy and the private property. At the same time, however, the dimension of the building is not that of a private orangery but rather that of a national institution. The aim of the project was, like a museum, to exhibit all the different species of palms, impressive and exotic, which came from the colonies around the world. In that period, the interest for botanic and natural sciences was increasing, and so the tendency to catalogue and a larger part of the population had access to pleasure activities, such as museums and parks. With the rise of the industrial city, moreover, nature had become the dream of the modern man. The taste for exotic plants, then, had different reasons. It was in part following the 18thcentury tradition of gardening and at the same time the contemporary social desire for nature in opposition to the city. Furthermore, it was a way to promote the Empire action in the colonies. The capacity to group, collect and display the ample variety of species was a manifestation of power and a proof of scientificity. When it was built, the greenhouse stood out for its dimension: 110 metres long with the central section 42 metres long, 30,5 metres wide and 21 metres high. The size, however, was soon surpassed by the Temperate House. What persisted as distinctive feature was the innovative nature of the project. Differently from the other cast iron buildings, the palm House did not present any heavy forms of decorations. It showed a very modern style. This allure depended on the will to have a very light structure and also as much sunlight as possible. To realize the bold and courageous structure a particular technique from the shipbuilding industry was used: the initial cast iron ribs were replaced by the wrought-iron ribs, which had a smaller section and a greater tensile strength. To manage with the structure of the vault, then, Turner used a very original type of purlin, which worked as a prestressed structure. The whole project, however, could count on the technological progress of the time. The heating system, for example, was supported by the introduction of steam technology, while the quality of the glass was achieved thanks to the necessity of development of the national manufacturing, which had to compete with foreign importation after the tax on glass was abrogated in 1845. The abolition of the fee, furthermore, made the cost of the material much less expensive.
The intent of the Palm House was to affect the visitor with its grandeur, with its size, structural quality and talent in displaying the achievements of the Colonial Empire. Today it still fascinates the visitors with its effects: the attraction of the tropical plants inside and the contrast between the enormity of the interior space and the slim thickness of the structure, between the height of its surfaces and the absence of continuous structural pieces, between the pure and rigorous image outside and the natural and complex perspective inside.
References: Hepper, F. N. Royal Botanic Gardens: Kew Gardens for science and pleasure. London: HMSO, 1982. Margolius, Ivan. Architects + Engineers = structures. London: Wiley-Academy, 2002. Marks, David, and Julia Barfields. www.bdonline.co.uk. 2013. (accessed February 25, 2016). Matveleff, Catherine. Palm House, Kew Gardens. London: Architectural Association, 1989.