Indigenous architecture as the basis of house design in developing countries: A case study evaluation of traditional housing in Bhutan

HABlTA

T, An lmernanonal

Journal.

Vol. I No. 314. pp. 207

217. Pergamon Press. lY7h. Printed mGrear

Braan.

Indigenous Architecture as the Basis of House Design in Developing Countries: A Case Study Evaluation of Traditional Housing in Bhutan DONALD

WATSON,

AIA and ALAIN BERTAUD

Architect and Environmental Design Consultant, Box 401, Guildford, CT 06437, U.S.A. Senior Planner, PADCO International, Washington, DC, U.S.A.

INTRODUCTION This paper discusses criteria for new housing design based upon traditional building solutions that are indigenous to a specific locale, climate, and culture. It is argued that the study of indigenous architecture can contribute to new building design criteria, which too often are based on styles and construction methods that are not properly matched to the ecological and cultural needs of a nation under development. Illustrative material is drawn from a case study of traditional housing in Bhutan. Because the Kingdom of Bhutan has been relatively isolated from external influences and began modern building programs only within the last decade, its traditional architecture represents long established practice still known to present day building craftsmen. However, most recently, due to vastly accelerated government sponsored building programs in Bhutan, new construction largely depends upon imported materials and labor, with only a superficial reference to traditional design. As a result, buildings are appearing which are out of context both with the cultural context, as well as the climate and local resources of Bhutan. The Outline of Economic Policy recently issued by the Royal Government of Bhutan sets forth several objectives of future economic planning that are directly related to the building sector, particularly housing: to improve living standards; to invest in productionoriented industries; and to develop the internal resources and man-power of Bhutan. Each of these goals can be affected by decisions in the building sector. This paper summarizes a case study survey of housing in Bhutan which was undertaken as part of a preinvestment survey. The survey lead to specific recommendations for improvements in building practice in terms of coordinated housing programme initiatives which could strengthen existing government efforts and which could be set in motion within the existing administrative and cultural structure of Bhutan. The range of elements considered include land use, building design, existing building materials, building products and industries, and administration. As the case study of indigenous building demonstrates, the quality of 207

208

Donald

Watson. AIA

housing in Bhutan can be best improved by existing building traditions of the country. building with recently introduced building shown to either be superior to recent buildings design innovation on the basis of criteria that (a) (b)

(c)

and Alain Bertaud

basing innovation within the context of the In detailed comparisons of both indigenous prototypes, traditional building design was or at least to offer a better starting point for address the following:

urban planning standards; design standards; building materials and methods, in particular

those which utilize natural resources the economics of product standardization product industry; institutional and administrative organization of housing.

more effectively and which introduce and perhaps some small scale building (d)

Table 1 below summarizes the entire range of criteria reviewed in the case checklist for comparing traditional and new building design. Although the case may represent an extreme example because its traditional architecture is so fully the same appreciation of indigenous building will lead to solutions that are neglected in the context of any rapidly developing society.

study as a of Bhutan developed, too often

DESIGN STANDARDS The items listed in Table 1 under the subheading Design Standards are discussed in this section in order to detail the specific examples considered within the case study method. The design of economic housing is at once one of the most complex and urgent problems throughout the world. In Bhutan, the problem is made difficult by a scarcity of resources that is inherent in the high transport costs of both indigenous and imported material. The availability of labour and skills, while abundant and sophisticated in particular sectors, is in a state of flux, with those Bhutanese craftsmen who are skilled in traditional construction becoming less available to the construction force. Potential economies of volume production and rationalization of building products have yet to be developed, although there are some products that could easily become standardized, in order to improve the use of natural resources, to make available higher quality products, and to lower total construction costs. Questions of design are discussed below with reference to traditional traditional house design; building and modern buildings under four subheadings: economics; health and safety; and climatic adaptation.

TRADITIONAL

HOUSE DESIGN

The extraordinary craftsmanship of traditional Bhutanese design is evident in all sectors The quality of decoration and workmanship of the country, even in the poorest dwellings. gives to both rural and urban settlements an aesthetic coherence that symbolizes the Bhutanese nation. More important than the decoration of the traditional Bhutanese house, its design, its setting in the land, and its process of construction, are the result of long practiced traditions of communal participation, family life and rural culture. The structure of the cultural attitudes embodied in traditional house design is part of the design problem. For example, it is possible to replicate the form of decoration in a new housing programme but lose the internal neighbourhood and family structure that gives coherence to the existing Bhutanese communities.

2

Y

f

3

% a

high

2.2

2.1

BUILDING

HO"93

AND

ECONOMICS

TRADITIONAL DESIGN

URBAN LAYOUT CIRCDLATION

1.5

law cost made possible by maximum use of local materials, self help and communal labor participation

Construction technique and decoration evolve from the same materials and craftsmanship and embody communal and religious ethos

Densely built settlements result in efficient circulation and offer protected circulation paths

variable to pre-

Closely grouped buildings fit well into terrain, often steeply sloped, in order serve arable land

AND

URBAN LAYOUT ?OPOGRAPHY

1.4

fanning camunities developed slowly identity and coherence to neighborinter-family structure

for

Rural farming communities are closely grouped; "WnaStarieS are planned around courtyards. In both cases, protected exterior spaces are formed which achieve good nicroclimatic moderation

Existing and give hood and

offer indigenous prototypes density settlements

DPaAN LAYOUT AND CLIMATIC CONDITIONS

URBAN LAYOW AND CULTURAL VALUES

1.2

ARCHITECTURX

Rural fanning communities and monastaries

INDIGENOUS

of Indigenous Archireciure

1.3

URBAN DENSITY

1.1

CRITERIA

Table 1. Comparison

BUILDINGS

in longer circuin negotiating

land

con-

to

High cost due to dependence upon imported material and labour

Attempts to imitate traditional decoration seem false, due to construction in new materials by workmen not familiar with traditional craft

Law density planning results lation distances, especially sloping terrain

Steep sites have not been used for new struction, with the result that arable is consumed for building

Low density planning misses the opportunity create protected outdoor spaces; no reccqnition of sun and wind orientations

Recent planning, based upon Western "suburban" layout, establishes no recognizable neighborhood or community groupings

Densities of recent planning is low, with the result that landuse is inefficient and arable land is removed from production

RECENT

and Hecenr Housing

z 2 B

2 t;

ij

FINISHED

3.4

WOOD TRIM

Fux)Rs AND CEILINGS

3.3

Tighter 3oinery in the window and door framing would be desireable for climate control and insect control. This would be possible by shop _ . productlo" cat*tԦ"dardWl"dDW components

Tighter joinery in the floor and ceiling construction would be desireable for control of winter heat loss and for insect control. This would be possible by rationalization of wood processing, allowing greater drying time and milling to provide lapped or t&g joznting

Standard window and door sizes should be adopted to rationalize wood seasoning and shop production. Current practice results in shrinkage cracks in all wood joinery

Concrete floor construction in multi-storied construction derives from need for fire and earthquake protection. High density duplextype house planning offers a" alternative to which traditional materials are suited

Concrete block, onewidth across, does not provide sufficient insulation or time lag for upland climates. Dirt is often present in the nwrtdr, resulting in rapid deterioration due to humidity and fungus in lowland regions

Newly imported metal corrugated roofing has often rusted at connections, causing frequent failures. as well as introducing a" aesthetically discordant element. NO provision has been made for insulating the roof area

Traditional method of recovering wood for shingles is wasteful of forest resources. Rationalization of shingle design and fabrication is possible. Open roof structure traditionally used for crop drying. Greater insulation capacity would be desirable by better ceiling construction

EXTERIOR WALL STRUCTURE Existing mud walls offer excellent capacity wall construction; technology could be improved to increase earthquake resistance using wood bracing

NO recognition of the different climatic variables between upland and lowland Bhutan has been made in adoption of single plan-types

Traditional housing demonstrates a wide variety of adaptions to different climatic conditions. Traditional materials, given some improvement in construction method, offer superior control of climatic conditions

3.2

Modern standards a+e met in new co"structio", particularly with introduction of the smokeless "chullah" and the "bokari" stove. Design for earthquake resistance in multi-storied concrete structures results in greatly increased costs

Improvements in traditional fireplace design, insect control and toilet design would be possible within the context of traditional house building practice and design

ROOF STRUCTURE

CLIMATIC ADAPTION

HEALTB AND SRFETY

B”II,DlNGS

RECENT

INDIGENOUS ARCHITECTURE

3.1

2.4

2.3

CRITERIA

Indigenous Architecture as the Basis of House Design in Developing Countries

211

To illustrate the inherent logic of traditional Bhutanese house design, Figs. 1 and 2 show examples of representative house types, the process of construction, its sophistication in the face of a scarcity of resources, and its variety of decoration. The resulting architectural style is thus directly related to the craft with which the building is constructed.

Fig. 1. Isometric of structuralsystem.

BUILDING

Typical rural house in Thimphu area.

ECONOMICS

Reduction in construction costs and improvements in design require a systematic view of the entire building process, from the initial raw material, its processing and transport

212

Donald

Wuison, AfA

nnd A fain Berfmrd

to the construction site, and its place in a sequence of construction economy in one phase may impose cost inefficiencies in another.

Fig. 2.

tasks.

Often,

an

Typical rural house rn Uplund Hhutun.

For the Bhutanese farmer who is undertaking house construction, traditional methods could not be more economical, given communal labour contributions, local materials, and in the case of wood, a subsidy in the form of a nornina “stump fee” that allows him to cut and transport logs for his house construction. However there are inefficiences in this the logging process is wasteful of the forest resources because so little of each process: tree is used; in the search of good wood for roofing shingles, many trees are cut open at the base to determine whether the grain is straight and those trees that are not suitable are left to rot; as a result, forest fires easily start in the small wood “slush” that is left behind. But in other respects, the traditional mud and timber construction epitomizes the maximum use of local materials. In terms of labour and material cost, there is ample evidence that local materials, if improved to meet higher standards of health and safety, offer the most fruitful point of departure for new standards of low-cost housing. In comparison, a detailed cost accounting of a standard government house plan type (Table 2), showed that over 80% of the construction cost for new single storeyed construction is in materials (for double storeyed construction, the figure climbs to 85%); approximately 64% of the construction cost in both cases involves imported materials (if one includes cement-related products made in situ). Such a tabulation identifies those elements of construction that are candidates for substantial cost reduction. (From the higher materials cost associated with double storeyed construction and the higher cost of concrete and steel work in double

213

IndigenousArchitecture as the BasisofHouse Design in Developing Countries

storeyed construction-47.9% of the total construction cost for two storeys versus 33.9% for one storey-the implication of structural design for earthquake resistance was seen to be critical). Table 2. Representative Percentages of Construction Tasks *Non-local materials = 64.7% Comparison

of ?Lpe III House - GTE Story and 'RioStory onestoLy/cmew Material

Material

w lbtal

1.28%

.56%

.14%

13.79%

1.88%

15.67%

.28%

-05%

.33%

.28%

.05%

.33%

4.26%

.32%

4.58%

12.80%

.97%

13.77%

13.06%

.69%

13.75%

.Ol%

25.3%

3.93%

2.52%

6.45%

2.56%

1.64%

2.12%

11.15%

9.03%

2.12%

Damph-oofcmrse *R.C.C. Work

stonemso *Hollow Block

-

Labor

1.28%

Earthwork

*Mild Steel

Ttmstory/one Total

.18%

Site Eevelopent

*concrete Work

Labor

1.28% .ll%

8.9%

24%

1.28%

-37%

.48%

1.22%

10.12%

--4.2% 11.15%

*Nan-local materials = 64.7%

HEALTH AND SAFETY An obvious criterion for house design standards is improved health and safety of the inhabitants. Several aspects of traditional Bhutanese housing deserve special mention to show that an investment in improved housing would result in higher health standards. There are three principal health and safety problems associated with traditional housing which may be susceptible to widespread change: the flueless fireplace, insect control, and toilets. A fireplace is essential to maintaining warmth in winter. However traditional houses in Bhutan are without chimneys, the smoke fills the room to leave via a window or opening to the roof area. Although the practice is accepted by Bhutanese in rural areas, the flueless fireplace creates conditions that are unpleasant and unhygienic: skin, eye, throat and lung hygiene is directly affected by smoke; the soot is deposited on the interior surfaces of the house; and there is always the danger of fire in the dry wooden roof structure. More efficient and safer space heating ovens could be devised using mud or brick wherein proper flue design would capture more heat in the masonry than exits by the flue.

214

Donald

Watson, AIA and

A lain Bertaud

A second problem is that of insect control within houses, particularly in food preparation areas. Tighter joinery of construction would reduce the passage of insects throughout the house interior. In the upland sections of Bhutan, the actual window area required for ventilation is not great, so that screening would not be excessive if restricted to only those openings required for minimum ventilation and to doors. The third problem of traditional housing is inadequate and unsanitary provision for toilets. Dry waste treatment systems, cesspool and septic fields are required for new housing, but also could be designed for introduction in existing settlements. Dry systems which process waste into compost are the closest to traditional practice in Bhutan.

CLIMATE Adaptability to specific climatic variables is one of the essential components of architectural design, particularly in Bhutan which is characterized by a wide variety of climates, each of which require different solutions. The tropical lowland areas of Bhutan will probably be the zone of whatever industrialization does take place due to its proximity to India. It is a hot-humid climate zone, with variations created by elevation and seasonal rains. Climatic design in this zone requires light weight structures with low thermal capacity and maximum provision for ventilation during all parts of the year, with particular attention to protection against wind-driven rain. This is in fact the basic prototype indigenous to the region (Fig. 3). Wood structures can meet earthquake resistance criteria, provided particular care is taken against insect damage and rotting. Masonry structures such as presently used in government standard plans compound the discomfort of overheating: in a hot-humid zone, the temperature variation between night and day is small; the temperature of masonry approaches a seasonal average which is above the human comfort level; as a result, the interior of the house is heated at night to temperatures above the outdoor ambiant. In contrast to the hot-humid lowlands, much of Bhutan is characterized by upland mountainous climate, which requires completely different building solutions. Table 3 shows temperature statistics from the Thimphu area averaged o\‘er four-year period. It shows a wide fluctuation of daily temperatures throughout the year (20% average daily temperature range) that is characteristic of upland mountain and alpine climate. Based upon similar temperature profiles together with humidity data that is not yet available, the significant design criteria for the climatic conditions for Central and Northern Bhutan could be identified. The dotted line in Table 3 represents the approximate seasonable temperature lag in building interiors that results from using materials that have a high capacity to store heat. Traditional houses of mud remain cooler than the outside air in early summer, enough to afford a natural cooling effect ashen outside daytime temperatures become uncomfortably warm (Zone A in Table 3). As the summer progresses the building mass would normally tend to heat up, but the cool nights even in the hottest part of summer afford sufficient cooling by ventilation (Zone B). In early fall. the heat storage effect similarly extends the warmth of the structure to protide natural heating above outdoor temperatures which begin to fall below human comfort levels (Zone C). III late spring, the same time lag keeps the temperature of the structure below outside air temperature, so that unless windo\vs are open to admit the warmth of the da),, more heating would be required.

lndrgenous

Archrtecture

as the Basis of House Design in Developing

F.ig. 3. Typicul rurol house in Lowland

Table 3. Representative

. .. ..... .

urn*

1.v

.I,.Ct

0,

high

C.O.CII”

Average

Temperature

Counfrres

215

Bhutan.

in Thimphu

Areu

,“,“,,,lO”

The design of protected courtyard spaces is an obvious response to the severe wind condition, affording enough climate moderation to grow species of fruit or other produce As shown by the layout of traditional farm that would not survive in exposed locations. By creating outside communes, clustering of houses creates mutual wind protection.

216

Donald Watson, AIA and Alain Bertaud

courtyards that benefit from direct and reflected radiation, with south-facing walls and windows devised to maximize direct solar heat gain in winter, the artificial heating requirement of the house can be minimized. In contrast, the construction of recent buildings have used concrete blocks as wall construction, which does not offer either the thermal capacity of resistance to create comfort without a greatly increased reliance upon artificial heating. Given further definition of the climatic variables encountered in Bhutan, such a list of design principles would be extended in order to determine how best to improve construction standards for climatic adaptation and for minimum reliance on artificial heating sources in winter.

SUMMARY Several complex issues are involved in housing in Bhutan: the future of its physical design and environment and the future of the rural culture that it sustains. On the surface, the use of imported materials has diluted the aesthetic character of the architecture and landscape of Bhutan. New building technology also has a latent impact on cultural habits. Over centuries, the rural settlements evolved into a complex dependence on land, community, and self-sufficiency, and became symbolized by the image of a cluster of wellkept homesteads placed on a hillside or in a valley, where every available piece of arable land is utilized. Given an integral culture, the environment too is coherent, and maintained as such so long as the culture remains intact. The challenge of any development programme is to respond to changes desired from within that culture-a society will wish, for example, better living and health standards for its members. A successful building programme must therefore be tailored to the ability of a given community structure to sustain progressive change. This can best be assured it there is sufficient reference to the existing cultural fabric, one measure of which is found in its indigenous architecture. The case study method described in this paper shows the potential contribution that can be made by a study of indigenous architecture.

Acknowled~emenfs-This paper is taken from a Report prepared by the authors for the United Nations Centre for Housing, Building and Planning (BHU/76/013). The authors The drawings were executed by Marie alone are responsible for the views expressed. Agnes Bertaud.

AUTHORS

RESUMES

Donald Watson, A/A is an Architect and Environmental Design Consultant in Guildford, Conn. In addition to the project reported in this paper, his international work has included building projects in Tunisia, North Africa, Scandinavia, and the United States. He has served as consultant in energy conservation projects for the United Nations, the Ford Foundation, and the U.S. Energy Research and Development Agency. He is on the Faculty of the Yale School of Architecture. Alain Bertaud is a seniorplanner and architect for PADCO, D.C. His recent projects have included the development politan Region (Haiti), and the first Karachi Metroville

International in Washington, of the Port-au-Prince MetroProject (Pakistan). He has

Indigenous Architecture as the Basis of House Design in Developing Countries

217

previously served as Town and Country Planner and Chief Housing Advisor for the United Nations Mission in Yemen and Architect Planner on the staff of the United Nations Centre for Housing Building and Planning.