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Global Architecture Platform

Tobacco Barns
in Sumatra

Tobacco Barns represent a globalized building type in which vernacular and modern structures are overlaid in the field of construction

Since the introduction of the first tobacco plantations in the mid-1860s, the landscape of Sumatra (Indonesia) has undergone a complete transformation. Today, the once dense rainforests stand as mere scattered remnants between settlements, transport infrastructures and plantations. Among the many different types of storage structures, the so-called tobacco barn represents a particularly distinctive building type, in which tobacco leaves are hung to dry. This causes the leaves to undergo curing, a biochemical refinement process in which water and farina is drawn out of them through a drying procedure that lasts between 17 and 21 days. Tobacco barns enable this process by capturing and modifying the monsoon winds. The crop rotation system of the plantations requires variable buildings that can be temporarily erected and rebuilt a few years later elsewhere.

The dimensions of the tobacco barns are significant: acreage of 25 by 70 m and a ridge height of 13 m speak to the demanding harvest rates, which this building type must accommodate. Tobacco barns are built entirely from the natural materials of teak (trunks), bamboo (rods) and sago palm (leafs). The materials are used as directly as possible; their processing for construction is reduced to a minimum. The entire surface of the building is composed of woven palm fronds of the sago palm that are freshly braided and installed on site where they are dried. No machinery and almost no tools are used. Instead, only human labour is employed for the construction of the barns along with a few locally available tools such as wire, pliers, saws, knifes and machetes as required.

The main objective of tobacco barns is the production of relatively uniform climatic conditions inside. This means that the three main climatic parameters – air temperature, relative humidity and wind velocity – must be brought under the control of tobacco producers. A successful curing process protects the leaves from larger fluctuations of these three parameters.

The most important factor in setting up the desired climatic condition inside of the barn is control of the winds. All tobacco barns have, without exception, the same orientation. This follows the angle of incidence of the Southeast Asian monsoon winds (NE-SW). Fierce winds of up to 45 knots (83 km/h) blow around the tobacco barns, which corresponds to storm winds at sea. The sago palm cladding is more than a simple interface between inside and outside. It is a complex, regulatory filter that modifies the incoming climatic factors such as wind, sun, rain, air without, however, isolating the tobacco leaves completely from them. Even with closed shutters, the facade remains permeable to air; the large surface area of the interwoven palm fronds has a high rate of moisture absorbency. A shutter system with a total of 110 flaps (approximately 30 along the longitudinal facades and roughly 25 along the front facades) offers the possibility of regulating temperature and humidity levels through cross ventilation. The flaps of the two front facades can be opened at a 60° angle by pulling bamboo rods.

Tobacco barns represent a globalized building type with numerous regional variants in different locations around the world. In these structures, vernacular and modern, informal and industrial influences are overlaid on top of one another. These barns are indicators how globalization leads to new man-made ecosystems and with them to new forms of knowledge in the field of construction. In this sense, they are part of a global (rather than national) history of construction.

Based on fieldwork conducted in 2013 and 2014 in the former Swiss colonial plantation “Helvetia” in the plantation belt around the city of Medan (Sumatra, Indonesia), Sascha Roesler investigated the structure of large-scale tobacco barns and the mechanisms of controlling their microclimates. One particular barn has been measured and various forms of representation have been fabricated (plans, photos, and diagrams).

13.Mar.2019 104 views 2 shares
Sascha Roesler Sascha Roesler

Sascha Roesler is an architect and researcher, working at the intersection of architecture, ethnography and science and technology studies. Since 2016, he is the Swiss National Science Foundation Professor of Architecture and Theory at the Academy of Architecture in Mendrisio, Switzerland (Università della Svizzera Italiana). Roesler, who holds a doctorate from the ETH Zurich, has published widely on issues of global architecture, sustainability and relocation. His publications comprise the first comprehensive global history of ethnographic research conducted by modern architects: “Weltkonstruktion” (Berlin 2013), and “Habitat Marocain Documents” (Zurich 2015), a volume on the transformation of a colonial settlement in Casablanca. Most recently, Roesler co-edited the anthology “The Urban Microclimate as Artifact” (Basel 2018).