Bamboo A Promising Green Building Material
What is Bamboo? • Bamboo is a grass, not a wood. • Extensive root system constantly growing underground Replenishes itself naturally • Grows naturally in biologically diverse forests throughout southeast Asia, South and Central America, and the Caribbean
Why Use Bamboo? • Bamboo stands release 35% more oxygen than equivalent stands of trees. • Some bamboo even sequester up to 12 tons of carbon dioxide from the air per hectare. • Bamboo can also lower light intensity and protects against ultraviolet rays. • It is very easy, affordable, and profitable for low income communities to grow and use bamboo.
More Good Reasons • Bamboo is one of the strongest building materials, tensile strength is 28,000 pounds per square inch versus 23,000 pounds per square inch for steel. • In Costa Rica, 1000 houses of bamboo are built annually with material coming only from a 60 hectare bamboo plantation. If an equivalent project used timber, it would require 500 hectares of threatened tropical rainforests. • 10-30% annual increase in biomass versus 2 to 5% for trees.
A High Yield Renewable Resource • "Ply boo" is now being used for wall paneling and floor tiles; bamboo pulp for paper-making; briquettes for fuel, raw material for housing construction; and rebar for reinforced concrete beams. • Diverse species makes bamboo adaptable to many environments. • It can be harvested in 3-5 years versus 10-20 years for most softwoods. • Bamboo tolerates extremes of precipitation, from 30-250 inches of annual rainfall.
In Limon, Costa Rica, only bamboo houses stood after a violent earthquake in 1992. Because it is flexible and lightweight bamboo enables structures to "dance" in earthquakes. • Bamboo is useful for different things at different ages:<30 days it is good for eating6-9 months for baskets2-3 years for bamboo boards or laminations3-6 years for construction>6 years bamboo gradually loses strength up to 12 years old
It is important to treat bamboo against rot and insects. One method is to cure the bamboo by standing cut culms on a stone for a month amongst the living culms. The leaves are left on as they continue to remove starch from culm. • The fabrication of bamboo requires very little energy, especially in comparison to other frequently used building materials. Concrete 240 MJ/M3 per N/MM2 Steel 1500 ‘’ Timber 80 ‘’ Bamboo 30 ‘’
Problems Facing the Bamboo Industry • In many places bamboo is disappearing. In Brazil there were 85,000 sq km of bamboo in 1976, while in 1983 there were only 32,000 sq km. It is feared that within a decade all bamboo in Brazil will be gone. Guadua is among the threatened species because it can only grows at tropical latitudes. • The perception that it is a poor persons housing material. In India, the highest castes use stone to build, the middle castes use wood, and only the lowest castes use bamboo.
Bibliography • http://www.rethink paper.org/content/fi_bamboo.cfm • http://www.ecowise.com /green/flooring/bamboo.shtml • http://www.bamboocentral.org • www.networkearth.org/natural building/bamboo.html