Working with giant grass

According to Chinese legend the craft dates back 5000 years, when Yau Chao-Shi, a mythological character whose birthday is still celebrated, taught his people how to construct nest-like bamboo shelters in trees. Bamboo grows up to 30 m tall. It reaches its full height in one year and persists for several years without growing taller or wider, making it technically a grass rather than a tree. It is nevertheless the world’s fastest growing woody plant and, as such, is particularly useful for stabilising riverbanks and preventing slope erosion. Bamboo stems can be harvested after three years and are self-renewing, with new shoots produced from the roots without replanting. The circular hollow stems make light and, when seasoned, tough construction poles that can be used without further processing or finishing.

Some 1250 species and 150 traditional applications have been identified for bamboo. Millions of people live in houses made of bamboo in parts of central and north America and Asia. It provides floor decking, wall panels, rafters, ceilings, roofs, doors and windows. Bamboo is also used for building fences and light traffic bridges in south Asia. Traces of bamboo scaffolding are still seen in south China, but in Hong Kong it continues to be extensively used, researched and improved.

The traditional art of bamboo scaffolding has been passed on from one generation to the next with little written information. However, with increasing interest from the construction industry, educational institutions, statutory departments and promoters of sustainable resources, there has been a steady growth in the number of written regulations, guidelines, codes, conferences and publications on the subject. The focus in Hong Kong is on the locally available bamboo types, namely kao jue and mao jue, the nominal external diameters of which at base are 40 mm and 75 mm respectively.

The Code of Practice for Scaffolding Safely was first published in 1995 by the Hong Kong Labour Department. The code provided practical guidelines to the construction and maintenance of both bamboo and metal scaffolds. It gave broad material specification and minimum requirements for the configuration of commonly used scaffold types. Loads on working platforms supported by the scaffolds, however, were provided only for metal scaffolds. A separate code for bamboos, entitled Code of Practice for Bamboo Scaffolding Safety, was published in 2001. This included the minimum imposed loads on working platforms and a performance specification.

In 2006, the Hong Kong Buildings Department published Guidelines on the design and construction of bamboo scaffolds to supplement the Labour Department code. The guidelines provide recommended practice for the design, erection, maintenance and dismantling of bamboo scaffolds. If scaffold layouts need to deviate from the guidelines, the Buildings Department recommends a performance-based design by a corporate civil or structural member of the Hong Kong Institution of Engineers. After gauging industry reaction, the Buildings Department will consider publishing a code of practice in the future.