Corrugated Bamboo Roofing Sheets

INTERNATIONAL NETWORK FOR BAMBOO AND RATTAN (INBAR)
TRANSFER OF TECHNOLOGY MODEL (TOTEM)
CORRUGATED BAMBOO ROOFING SHEETS
Research Centre for Forest Ecology and Environment, Forest Science Institute, Chem, Tu Liem, Hanoi. Vietnam

CONTENTS

TRANSFER OF TECHNOLOGY MODELS (TOTEMs)

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CORRUGATED BAMBOO ROOFING SHEETAS AT-A-GLANCE 6

PART ONE: INTRODUCTION

1. Corrugated bamboo roofing sheets

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2. History of the development of corrugated bamboo roofing sheets in Vietnam

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3. General development attributes and advantages

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4. Suitable agro-ecological regions

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5. Target groups

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6. Benefits

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7. Scope for small enterprise development

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8. Requirements for success

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9. Potential improvements and research needs

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Concluding remarks

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PART TWO: MANUFACTURING OF CORRUGATED BAMBOO ROOFING SHEETS (CBRS)

1. Introduction to CBRS manufacturing

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2. Production of CBRS

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2.1 Preparation of raw materials

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2.1.1 Cross cutting and splitting of culms

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2.1.2 Slivermaking

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2.1.3 Mat weaving

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2.1.4 Preservation of bamboo mats

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2.2 Resin manufacturing

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2.2.1 Resin synthesising equipment

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2.2.2 Raw materials

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2.2.3 Resin manufacturing

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2.3 Resin application

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2.3.1 The resin applicator

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2.3.2 Procedure

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2.4 Pressing 2.4.1 Laying up 2.4.2 Equipment
2.5 Trimming
3. Comprehensive input requirements 3.1 Capital costs 3.2 Tools and machinery
Appendices

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19 19 19
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TRANSFER OF TECHNOLOGY MODELS (TOTEMS)

Transfer of Technology Models (TOTEMs) are focussed educational tools providing relevant information and distance training on one specific area of bamboo/rattan management, processing or utilization. They are a means of technology transfer between similar regions throughout the world, with the emphasis on South-South transfer for livelihood development. They enable those involved in the management and use of bamboo and rattan resources to more efficiently and effectively develop and use skills relating to these resources.
TOTEMs are primarily intended as practical information resources and teaching aids for those at the local extension level in their communities, who can utilize them to assist local community development. Each TOTEM consists of a detailed written report of the technology, a PowerPoint presentation, a film, and, where relevant, a set of technical photographs. They also include information on target users, financial analyses of sample set-ups from the partner country preparing the report and information on where to source particular technologies (such as equipment). The TOTEM thus provides all the information required for establishing similar technologies within interested countries and regions.
• The report contains all the technical details of the particular processes involved, as well as other relevant information for establishing the technology such as costs of business establishment, running costs and cash flows.
• The PowerPoint presentation contains details of the relevant technologies and their applications, and is intended to provide an overview of the potential of the technology for development.
• The film provides a visual guide to the processes involved and helps to bring them alive in the minds of the learners.
The different parts of the TOTEM are targeted at slightly different audiences, via the local extension workers. The report and film are intended to be the main means of extension to the individuals and communities who will implement the technology and who will directly benefit from it. The PowerPoint presentation is primarily intended as a tool for the extension worker to sell the technology and its role in development to those who provide the infrastructural, policy and financial support for its implementation, such as government departments, donors and NGOs. There is considerable flexibility, however. Local extension workers will be able to incorporate the TOTEMs in their own work as they wish and adapt and develop the TOTEM to suit their particular requirements and conditions.

This TOTEM on the production of corrugated bamboo roofing sheets has been produced by the Forest Science Institute, Hanoi, Vietnam. It may be used alone, or in conjunction with the TOTEMs on the bamboo splitting and slivering unit and matboard production unit, both of which have been produced by the Indian Plywood Industries Research Institute, Bangalore, India.
The report part of this TOTEM describes the technology for establishing facilities and producing corrugated bamboo roofing sheets for rural development in regions where bamboo is available as

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Transfer of Technology Model: Corrugated Bamboo Roofing Sheets Unit

a raw material. It is intended to be used in conjunction with the illustrative film included in this TOTEM package
The first part of the report introduces the technology, discusses its history, its development attributes, its benefits and it’s applicability. The second part of the report provides detailed information on the technical aspects of producing roofing sheets. Appendix I details the method used in China to produce corrugated bamboo roofing sheets. The costs of producing a standard size of roofing sheet are shown in Appendix II and the equipment costs are shown in Appendix III. A bibliography is given in Appendix IV.
This TOTEM is one of the first to be produced by INBAR/FSI and your feedback is most welcome - kindly contact INBAR or FSI with your comments or suggestions.
© International Network for Bamboo and Rattan 2001

Note 1: This TOTEM has been edited at INBAR and differs from the form in which it was received from FSI, Hanoi.
Note 2: All financial calculations are in Vietnamese Dong. At the time of writing 1 USD = 14, 600 VND.

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Transfer of Technology Model: Corrugated Bamboo Roofing Sheets Unit

CORRUGATED BAMBOO ROOFING SHEETS AT-A-GLANCE
What are corrugated bamboo roofing sheets?
Corrugated bamboo roofing sheets (CBRS) are an excellent alternative to corrugated asbestos, iron, plastic or zinc roofing sheets. They are produced from natural materials and are attractive, durable and resilient to adverse weather conditions and pest attack. They can be produced in a range of standard sizes and can be used to roof dwellings, stores, animal pens and other buildings.
How are they produced?
CBRS are produced by pressing firmly together woven bamboo mats that have been impregnated with an adhesive resin. The corrugations are formed by pressing them between corrugated pressing plates in the pressing machine.
What is the market for corrugated bamboo roofing sheets?
The market for CBRS is somewhat variable in different regions of the world but depends to a large extent on successful marketing strategies. CBRS is popular in rural areas where the low prices are attractive. The potential to increase the use of CBRS in more affluent areas is enormous, and there is considerable export potential in the markets of the more affluent countries where their eco-friendly nature could be a major selling point.
What is the role of a corrugated bamboo roofing sheets unit in rural development?
The unit itself will provide employment to a range of people and there will be extra employment generation in its forward and backward linkages, such as cultivation and harvesting of bamboos, primary processing, mat weaving, marketing and retailing. A unit producing 500, 000 m2 of sheets per year will require a total workforce of over 200 people. The need for a sustainable supply of raw materials will encourage the proper management of bamboo stands, and the establishment of new plantations, with their associated environmental benefits.
How do I establish a corrugated bamboo roofing sheets-making enterprise?
A corrugated bamboo roofing sheets manufacturing unit requires a regular supply of bamboo mats, electricity, labour and access to markets. An enterprise with a capacity of 500, 000 m2 per year can be established for approximately USD $26, 000 in Vietnam but costs will vary in other countries.

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Transfer of Technology Model: Corrugated Bamboo Roofing Sheets Unit

PART ONE
INTRODUCTION
DEVELOPMENT ATTRIBUTES, TARGET GROUPS and BENEFITS of a
CORRUGATED BAMBOO ROOFING SHEETS MANUFACTURING UNIT

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Transfer of Technology Model: Corrugated Bamboo Roofing Sheets Unit

1. Corrugated bamboo roofing sheets
Corrugated bamboo roofing sheets (CBRS) are produced from woven mats of bamboo that are soaked in adhesive resin and then pressed firmly together. The corrugations are formed by pressing the mats between two corrugated pressing plates. The sheets can be produced in a range of sizes to suit particular requirements and can easily be trimmed for special situations. Bamboos are the only raw material used for the sheets. The sheets are durable and stable and resistant to pest attack, severe weathering and fire.

2. History of the development of corrugated bamboo roofing sheets in Vietnam
The Centre of Experiment and Transfer of Techniques of the Forestry Industry, part of the Centre of Forest Industries at the Forest Science Institute of Vietnam, has been producing and developing corrugated bamboo roofing sheets on an industrial scale since 1992. Bamboo mats have been produced here since 1982, and the technology for producing both mats and roofing sheets has been transferred to many processing enterprises, where they have been widely used. Many regions (communes, districts) have been established in Vietnam to specially supply raw bamboos for the units. Many of the units do not just produce roofing sheets. The technology for producing roofing sheets is almost the same as that for producing mats, and the equipment required is very similar, so most of the units produce roofing sheets, matboard and bamboo flooring concurrently.
In the earlier days of the first “Doi Moi” period in Vietnam when the service sector was developing strongly there was very high demand for the roofing sheets and matboard for the construction of temporary bars and restaurants. At the same time, CBRS have been used in many public locations and the demand for their use in the construction of temporary houses for workers was also very high. There is now considerable competition from corrugated plastic, metal and cement roofing sheets in the cities, but in the countryside, especially in the poorer, mountainous areas, CBRS are still widely used especially because they are competitively priced.
The technology was first developed in China, from where much of it was transferred to Vietnam. The Indian Plywood Industries Research and Training Institute in Bangalore has also developed roofing sheets technology.

3. General development attributes and advantages
The main development attributes of the technology are as follows:
• Increase in area of bamboo plantations will benefit the environment and protect precious forest resource through substitution of bamboo wood for timber.

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Transfer of Technology Model: Corrugated Bamboo Roofing Sheets Unit

• Rehabilitation of degraded forests and other waste lands. • Creation of employment opportunities in bamboo cultivation, splitting, mat weaving
and the CBRS unit itself. • Opportunities for family members, particularly women, to spend their free time
weaving bamboo mats at or near their homes. • The CBRS unit is not a capital-intensive project but is labour-oriented and develops
the small-scale industry in rural and mountainous regions.
The main advantages of the technology are:
• CBRS are an environmentally friendly and safe alternative to asbestos, zinc or corrugated iron roofing panels.
• The sheets are also quieter in the rain than metal roofing panels. • The sheets are durable and strong with excellent internal bond strengths and high
resistance to weathering and biological agencies such as insect attack. • They have a natural appearance.
4. Suitable agro-ecological regions
The CBRS technology is suitable for bamboo growing regions that can supply the raw material for their production. Regions of natural bamboo forest are suitable, but CBRS could also be produced in areas where bamboo is grown on plantations or in homesteads. Management of plantations and natural stands is highly desirable, both to guarantee a standard level of supply to the unit and to maximise the benefits of the plantation to the owner and cultivators. The technology is especially suitable for areas where bamboo plantations are desirable for the restoration of degraded forests or wastelands such as abandoned shifting cultivation areas, or where bamboos can be grown to reduce soil erosion, particularly on steep slopes in high rainfall areas.
5. Target groups
There are three main target groups of the CBRS unit. The first are those who will be employed by the unit itself. Unskilled, semi-skilled and technically trained personnel will all be required. The second group are those who weave the mats from which the sheets are made. Many of these people are women who will be able to weave at home in their spare time and who will benefit from the regular income. The final group are those who will cultivate and harvest the bamboos. This group includes ethnic minorities in mountainous regions, homestead owners who may cultivate a few bamboos on their plots and plantation workers. If the unit is established as a cooperative venture within the community it will also benefit the community as a whole and lead to increased prosperity. Finally there will be increased opportunities for transporters, wholesalers and retailers.

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Transfer of Technology Model: Corrugated Bamboo Roofing Sheets Unit

6. Benefits
The environmental benefits of the unit are considerable. The use of large quantities of bamboo in the production of mats promotes the sustainable management and increased area of plantations of bamboos. The cultivation of bamboo is also beneficial for soil conservation and afforestation activities and plantations are often encouraged as part of social forestry programmes.
As already noted, the employment opportunities for a range of people in rural areas are considerable. A unit producing half a million square metres of roofing sheet per year will create employment for 200 people, most of whom will be required for the production of bamboo mats. More economic activities will be created in the region, particularly in the marketing and selling of the sheets, and the social and cultural conditions of the communities involved should improve as a result. Opportunities for export should also be explored to earn foreign exchange.
7. Scope for small enterprise development
There is considerable scope for the development of small CBRS-producing enterprises. Corrugated bamboo roofing sheets are particularly popular in poorer, rural, mountainous regions due to their inaccessibility, the proximity of natural raw materials and the low cost of the sheets. Given some effective marketing the sheets could easily be popularised in more affluent areas and in affluent countries, where eco-friendy products are very popular. In this case the establishment of a vigorous sales department within the unit, or at a local or community level to pool resources from a number of units and act on their behalf would be beneficial.
The establishment of a corrugated bamboo roofing sheets unit requires an estimated capital investment of approximately USD $25, 500 in Vietnam (Appendix III), although costs would vary depending on the country, and the region. It may be possible to apply for incentives/benefits offered by the government for the establishment of small-scale enterprises - check with your local government office or business advisory centre for details.
8. Requirements for success
The essential requirements for a successful corrugated bamboo roofing sheets unit are:
• Start-up capital • Land • Regular supply of raw bamboos for weaving into mats

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Transfer of Technology Model: Corrugated Bamboo Roofing Sheets Unit