clay wood stone metal adobe plaster Traditional Materials and Construction Technologies used in the Kathmandu Valley Caterina Bonapace and Valerio Sestini United Nations Educational, Scientific and Cultural Organization Traditional Materials and Construction Technologies used in the Kathmandu Valley Caterina Bonapace and Valerio Sestini The authors are responsible for the choice and the presentation of the facts contained in this book and for the opinions expressed therein, which are not necessarily those of UNESCO and do not commit the Organization. The designations employed and the presentation of material throughout this publication do not imply the expression of any opinion whatsoever on the part of UNESCO concerning legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. Printed by : Paragraphic for the United Nations Educational, Scientific and Cultural Organization 7 Place de Fontenoy, 75352 Paris 07 SP, France November 2003 View of Kathmandu From W. Kirkpatrick, 1811 Foreword This book is the result of a close collaboration between an architect and an anthropologist. Such an interdisciplinary team was essential since the Nepalese culture, environment and religion are so unique and intricate, that it is necessary to tackle the subject matter from different angles, in order to provide the additional information and elements needed to grasp the essence of the subject. This book deals with architectural features which focus on construction materials and techniques, and promotes their appropriate use in the rehabilitation, refurbishment and restoration of the historic buildings of the Kathmandu Valley. Not only in Nepal, but also globally, the preservation of our cultural heritage, and the reuse of the built-up environment, play a major role in the improvement of our physical environment, which includes schools and educational facilities. The authors, Professor Valerio Sestini and Dr. Caterina Bonapace, are dedicated professionals with specialised knowledge of this part of the world. Professor Sestini teaches at the University of Florence and started working in Nepal as early as 1971. Dr. Bonapace wrote her doctoral thesis on 'The Bagmati River in the Kathmandu Valley', and joined Professor Sestini in 1997. They have carried out research together for many years with great enthusiasm and commitment. Their present research is based not only on several years of study and visits to remote parts of Nepal and India, but also on ad hoc missions related to specific aspects of the architecture, history and social and economic background of the country. For the preparation of this book, which began in late 1999, a number of special missions were carried out in Nepal and India, and to specialised libraries in Paris. The authors are of the opinion that architecture should be considered not only as the result of time and knowledge, but also as the reflection of a certain epoch. This is why attention was paid equally to monumental and traditional architecture, which share similar construction materials and techniques, although the levels of refinement are different. To reaffirm this, visits were paid to construction sites, where rehabilitation or restoration work was under way, to quarries and forests where raw materials were still to be found, and kilns or laboratories where these materials were transformed into the primary products used for construction. During these visits interviews were conducted to record information and data, particularly with regard to the modifications introduced in the 'production' processes. The results of the investigations and interviews confirmed that the same technical skills of the Newar artisans of the past are still available today, and there is continuity in the provision of such highly specialised work. Also investigated were the rigid division of work based on the caste system still in place, and the extent to which the continuity of specialised work still remained within the same family, as was the case in the past. In-depth studies on the effects of earthquakes on traditional constructions were completed, and preliminary studies made. The book is structured in such a way that each chapter focuses on a specific construction material and techniques, and covers such matters as where the raw materials were found, the way in which they were transformed into construction elements, and finally on the assembling techniques used. Numerous explanatory photographs and drawings are included in order to enrich the text. This book covers all of the above-mentioned issues. It is not just a collection of information concerning the Nepalese architectural heritage, but is also a means of transmitting important skills and knowledge from the past to the present. It will serve as a useful and handy reference manual for architects and other experts. But it will also be an intellectually stimulating book for students, and all those interested in Nepalese culture, architecture and society. Alfeo Tonellotto i Acknowledgements We, the authors express our profound gratitude to UNESCO, the Italian Ministry of Foreign Affairs, the University of Florence and the Department of Technologies applied to Architecture and Design "Pierluigi Spadolini" for the valuable financial support contributed for this research. We also wish to record contributions and technical cooperation rendered by many individuals, without whose help this publication could not have come out at this quality level: First and foremost, we would like to express our sincere thanks to Mr Alfeo Tonellotto, Chief, Architecture for Education Section, UNESCO HQs, for his continued professional support and total involvement at all stages in the preparation of this publication. For the fieldwork, we are very thankful to our interpreter and guide, Mr. Sange Lama, for his efficient services during our visits to several places, workshops and laboratories. Also many thanks go to all those Nepalese craftsmen and workers for their hospitality in opening to us their workshops and for generously providing us with valuable information on their skills and knowledge in craftsmanship Special thanks is extended to our colleague architects Mr Vincenzo Gabriele, Mr Paolo Sestini, and Riccardo Somigli for their ingenious contributions in preparing many drawings contained in this book in electronic format, and last but not least, Ms Barbara Brink for the graphic design and final text editing. We would also like to note that the surveys of historic buildings, monuments, and artefacts were carried out by Mr Vincenzo Gabriele, Mr Paolo Sestini, Mr Valerio Sestini, Mr Enzo Somigli, Mr Riccardo Somigli, Ms Claudia Sacchi and Ms Cristina Albertini. All photos contained in this book come from original photos taken by the authors. iii CONTENTS CHAPTER 1 - introduction 1 A living history 3 The origins 4 Malla centuries 8 The Newars 10 New styles 12 Recent developments 15 CHAPTER 2 - Clay, bricks and tiles 19 Clay, bricks and tiles 21 Clay, the basic material 22 Kilns 28 Types of products and their applications 33 The traditional craftsmen 41 Thimi kiln 41 CHAPTER 3 - Wood 45 Wood 47 Traditional types of wood and their origin 49 Construction elements 53 Roofing 54 Vertical elements 60 Stairs 65 Floors 66 Doors and windows 67 Traditional craftsmen 71 CHAPTER 4 - Stone 77 Stone 79 The shikhara 80 Public works and fountains 84 Sculptural works 88 Chaitya and stele 92 Houses 94 Quarries 94 Traditional craftsmen 95 CHAPTER 5 - Metals and alloys 99 Metals and alloys 101 The ‘lost wax’ process 104 Bell casting 107 Iron 108 Traditional craftsmen 110 CHAPTER 6 - Adobe 115 Adobe 117 CHAPTER 7 - Plasters 125 Plasters 127 Lime mortar 130 CONCLUSION 139 Conclusions 141 APPENDIX I 147 APPENDIX 1 149 Laboratory analysis 149 Earth 149 Stone 150 Plaster 151 v APPENDIX II 153 How adobe constructions respond to earthquakes 155 Seismic movements 157 Structural seismic resistant design 157 Structural improvements for existing buildings 158 Technical innovations 158 BIBLIOGRAPHY 161 GLOSSARY 165 PLATES AND TABLES Plate 1.1 - Stone sculpture of Vaikhunthanatha (Vishnu), Changu Narayan complex 6 Plate 1.2 - Stone sculpture of Brahma, Changu Narayan complex 6 Plate 1.3 - Vishnu sleeping on Ananda snake, Boudhanilkantha 7 Plate 1.4 - Teleju Temple, Darbar Square, Kathmandu 8 Plate 1.5 - Typical plans of dega temples 9 Plate 1.6 - Maju dega, Darbar Square, Kathmandu 11 Plate 1.7 - Jang Hiranya Hem Narayan temple, along Kathmandu ghat, 19th century 12 Plate 1.8 - Royal Palace, partly renewed in the 19th century, Kathmandu 13 Plate 1.9 - Singha Darbar built in 1903, Kathmandu 14 Plate 2.1 - A clay quarry with bricks drying in the open air 23 Plate 2.2 - Preparation of the clay and its insertion into the mould 23 Plate 2.3 - Flattening of the fair-face of the daci appa with a mallet 24 Plate 2.4 - Fair face of brick is smoothed with a knife 25 Plate 2.5 - Knife used for cutting bricks 25 Plate 2.6 - Clay tiles dry in the open air 26 Plate 2.7 - Different tools are used for the final touches to the decorated bricks 27 Plate 2.8 - Cleaning process 27 Plate 2.9 - Hoffman kiln 28 Plate 2.10 - Hoffman kiln chimneys 29 Plate 2.11 - Loading coal into a Hoffman kiln 30 Plate 2.12 - Loading bricks into a Hoffman kiln 30 Plate 2.13 - Intermittent kiln 31 Plate 2.14 - Bricks are unloaded from an Intermittent kiln 32 Plate 2.15 - Daci appa bricks dry in the open air 33 Plate 2.16 - Bricks used for frames and other decorative elements 34 Plate 2.17