Each country around the world traditionally used some kind of wood to make scaffolding.
Europe used fir and pine beams, tied together with hemp rope. Unfortunately, wooden beams are heavy for the weight they can bear, so above a certain height scaffolding made from wood would collapse under its own weight.
Asian countries, however, were fortunate enough to have a plentiful source of a lighter and stronger natural material than pine: Bamboo. These countries still use bamboo in much of their scaffolding today as it has many advantages over steel.
Why is bamboo used for scaffolding?
Bamboo is a variety of grass, the fastest growing plant in the world, and plentiful in East and Southeast Asia.
As such bamboo is also a very cheap material to use, with a strength-to-weight ratio similar to wood. The difference is that bamboo is hollow, and thus a lighter weight for the lower parts of the structure to bear.
Is bamboo scaffolding as strong as steel?
Steel has a higher tensile strength overall (400N/mm2 vs ~160N/mm2), and compression strength (250 N/mm2 vs 40-80 N/mm2), so steel is in all ways stronger, but bamboo is stronger in proportion to its light weight.
Bamboo is so light that experienced bamboo workers often literally throw the beams around from person to person, floor to floor. The result is that bamboo is five to six times quicker to erect, and 10-12 times quicker to deconstruct. This labour time saved makes the use of bamboo as a scaffolding material even cheaper.
No surprise it is still in frequent use.
The use of bamboo scaffolding for high-rise buildings
The use of bamboo as scaffolding is common throughout East Asia for it being so plentiful, and therefore much cheaper relative to steel.
Approximately 5 million lengths of bamboo are used each year in Hong Kong, and the port through which it is transported is via Macau.
While bamboo is commonly used in East and South East Asia, only Hong Kong and Macau continue to use bamboo for anything higher than a mid-level building.
There is a particular skill in securing a high bamboo structure at key points so that it will not bend. Maintaining the industry is the only way to preserve the skill of building bamboo scaffolding to that height.
Hong Kong and Macau have managed to keep the skill of bamboo scaffolding alive through culture and tradition, leading to these to areas being the only places still using bamboo scaffolding for high-rise constructions.
Bamboo scaffolding in Hong Kong
Hong Kong maintains a strong cultural tradition, for which those skills are needed every year in the construction of ‘Bamboo theatres’.
The main cultural festivals in Hong Kong are the New Year celebrations between March and April. The tradition at this time of year is to construct many “Bamboo theatres”, attended by great numbers of Hong Kong families. Thus families of bamboo craftsmen pass on their skill and knowledge and proudly keep this tradition alive.
Bamboo scaffolding in Macau
Macau has also kept the skill of bamboo scaffolding alive through traditional culture: each year a temple is constructed to offer good luck and protection to sailors.
The Portuguese architects who saw this were so impressed that they encouraged the art to continue. Nowadays, in an effort to maintain the tradition, Macau also encourages bamboo sculpture exhibitions.
Making bamboo scaffolding
From grassroots to building top, here are the steps to make bamboo scaffolding:
1. Grow the right species and prepare the lengths
The foundation of a bamboo structure is Gaozhu, which comes from the species Bambusa pervariabilis. The other variety is Maozhu, which is thicker and longer, from Phyllostachys edulis.
These take 3-5 years to grow, and after harvesting need to be stored for three months so as to completely dry out. Those with cracks or rot are discarded. Bamboo must also be stored dry throughout its life so as to prevent fungal rot.
Each beam is around seven metres long, used approximately three times and discarded once they show signs of weakening or cracking.
Bamboo takes one-fiftieth of the power to produce than it takes to make steel, and along the way absorbs up to five times more carbon dioxide and produces 35% more oxygen than an equivalent grove of pine trees. Without, of course, the need to mine for metals.
2. Choose your foundation points
The builder starts by selecting the best place to put the foundations. Points which will bear the weight of the structure and its occupants.
The ability to make highrise bamboo structures comes from knowing where to support them at various heights up the scaffolding. Bamboo may be strong, but it is also flexible, and when not reinforced above a certain height they will ‘dance’. This will test even the best ties and pull the structure apart.
3. Build the mainframe
In Hong Kong the names of varying thicknesses of the bamboo are:
- Mao Jue which are 75mm wide with 12mm walls, used for strength and load-bearing, and;
- Kao Jue, 40mm wide, 10mm walls, used horizontally and diagonally for platform construction and bracing support.
Start with the vertical poles known as “zam” (the needle), lash them together with the horizontal beams called “hin”, and reinforce with diagonal poles known as “cheong”.
With this several squares of structure are made, each around 75cm wide and high.
Making good ties is much of the craft in bamboo scaffolds, and it is said that an experienced bamboo scaffolder can tell how experienced was the person making a scaffolding just from the quality of the ties.
It is an art that can be improved throughout the lifetime of the scaffold builder, who must earn trust through experience over many years.
A new bamboo worker will be under apprenticeship for two years before even being trusted with a tie, and then in the middle rank under the supervision of a master before they can prove themselves capable of trustworthy ties and be considered masters themselves.
Traditional natural materials have since been replaced by more durable nylon ties so that they still grip, but do not rot or break.
Why don’t we use bamboo scaffold in Australia?
For all the benefits of bamboo’s light weight and environmentally friendly production, Australia has neither the resources nor the skill to make bamboo scaffolding, and Australia is rigorous in safety.
Steel is far stronger, and aluminium almost as strong for a lighter-weight option, with the advantage that these can be made to a consistent strength and shape.
This means that Australian safety standards can be decided around the reliability of metal scaffolding, and this safety does rely so heavily on the expertise of the person erecting the structure as is the case with bamboo scaffolding.