Use of Bamboo as a Building Material
Bamboo is the oldest and most popular building material in the rural areas and villages in the tropical and subtropical regions of the world.
In the tropics, bamboo is abundant and inexpensive to acquire. It is the most popular material for low cost housing as well as a variety of domestic uses. In house construction, bamboo is used for both structural and non-structural elements of the house. The structural elements are the columns/posts, floor joists, beams, roof rafters and purlins. The non structural elements are the walls, floor boards or mats, stairs, ceiling and roof covering.
Other domestic uses of bamboo are furniture, storage baskets, rice cooking pots, fuel (damaged and low grade bamboo), fans, umbrellas. Bamboos are also used in fences, foot bridges, overpasses, reinforcements in concrete hallow blocks, scaffolding, conduits for water and irrigation.
Preservation Treatment of Bamboo
Bamboos are highly susceptible to deterioration agents - insects, rot, fungi, and fire. Houses built with untreated bamboo have to be replaced every two to three years. Simple popular wood preservation methods extend the durability of the bamboo material to about ten years which is approximately four times the span of untreated bamboo. Following are some preservation measures:
Bamboo poles should be stored horizontally, laid above ground and supported to prevent sagging or bending.
Bamboos should be stored in a dry, shaded and well cooled area, laid in shelving type system with the first layer not less than 50 centimetres above ground level for good air circulation.
Smoking fires or heating bamboo in kilns can protect the canes from insect attack.
Applying chemical coating such as are kerosene, diesel oil containing DDT and varnish can protect the canes from termites, beetles, wet rot and fungus attack.
Bamboo for Posts ands Frames
Bamboo columns/posts are driven directly to the ground. Untreated bamboo posts which are in contact with the soil are usually treated with a fungicidal preservative e.g. pentachlorophenol. Bamboos that are used as posts or columns are the culms that are fairly larger in diameter, thicker walls and nodes close together for maximum resistance to bending.
Bamboos may be used for corner posts, girders or plates, joists, studs or braces, tie beams, king posts, purlins, ridgepoles, rafters, sheathing. Mortise and tenon joints cannot be used for joining bamboo frames. The cut drastically reduces the ultimate strength of the bamboo culm. The notch or saddle like cut is the best method for joining bamboos.
Bamboo for Flooring
Bamboo floors are normally raised above the ground. Raised floors are more hygienic and provide better ventilation. Smaller whole culms or strips of bamboo boards lashed or nailed together are used for flooring.
Bamboo for Walls
Whole culms or longitudinal halves are used for walls. These may be laid vertically or horizontally. Crushed bamboo secured vertically by bamboo clips and supported by bamboo studs can also be used.
Bamboo for Roofing
Bamboo tile and thatched roofing can be used. Bamboo tile roofing is the simplest form of bamboo roofing. It is made of halved bamboo culms running full length from the eaves to the ridge. The first layer of tile is laid side by side with the concave face upwards and tied to the purlins with bamboo rope ties. The second layer is then placed over the first with the convex face upwards.
Thatched roofing is made of coconut palm leaves with a bamboo frame for the base. The frame may consist of vertical bamboos 40 millimetres in diameter laid 30 centimetres apart over which split bamboos are securely fastened at right angles 15 centimetres apart.