|Journal of the Network of African Countries on Local Building Materials and Technologies - Volume 1, Number 3 (HABITAT, 1991, 46 p.)|
* Submitted by Mr. N.L. Hall, Intermediate Technology Development
Group (ITDG), Nairobi, Kenya.
Coconut palm leaves are one of the most widely used materials for rural roofing. But there are many different ways of preparing and using the leaves and durability varies by a factor of 2 or even 3 times. The Intermediate Technology Development Group has been interested for some years to encourage the adoption of better thatching techniques. ITDG's programme started with research into the many different traditional and current methods used in Europe, Africa, Asia, the Pacific and Central America. This research has led to the Group supporting several projects aimed at upgrading local techniques and making optimum use of local renewable materials for rural housing.
In Africa the group has run training courses to improve grass thatching skills, whilst in South India it has supported the Centre for Appropriate Technology in Nagercoil in testing a chemical treatment process intended to double the life of coconut-palm thatch. Unfortunately, the cost benefits of this process have recently been negated by increasing prices of the chemicals. A new approach is now proposed.
With South India in mind the building materials sector of ITDG has studied the palm thatching (makuti) methods used in East Africa where roofs are reported to last up to eight years, if properly thatched. A South-South technology transfer was tested in August 1990 by introducing these techniques to South India where even the chemically treated thatch lasts only a maximum of four years.
The main difference between South Indian and East African palm thatching is in the preparation of the leaves. In India the leaf fronds, still attached to the central rib, are plaited together to make panels of thatch. In East Africa the fronds are stripped from the rib, then stitched on to a batten. By observing the way water flows off the roof, it is obvious why the Indian style thatch is less durable. The plaited surface encourages a zig-zag flow pattern, thus hindering rapid water discharge and hence accelerating leaf decay, whereas water flows directly and rapidly from a makuti style roof. The key to durable thatching of any type is to lay the grass or palm leaves in a way that allows rainwater to flow off the roof quickly. A steep pitch (minimum 45 degrees) and careful workmanship are most important.
ITDG's collaborating partner in India, the Centre for Appropriate Technology at Nagercoil, will be assessing the technical, economic and social viability of encouraging the adoption of makuti style thatching. ITDG will evaluate results and then disseminate relevant information to ensure maximum replication to other palm-thatching regions via the Building Advisory Service and Information Network (BASIN).
For more information, contact ITDG., Myson House, Railway Terrace, RUGBY CV21 3HT, England.