1. BAMBOO AS A CONSTRUCTIVE BUILDING MATERIAL
Both hardwood and bamboo can be used for supporting structures in the building as well as surfaces like floors, walls, roofs.
So what are differences between bamboo and woods in terms of sustainability?
One of the most obvious differences is the speed of growth.
Bamboo categorised as a grass, can be ready for construction within 5 to 7 years. Hardwoods require at least 35 years.
The speed of growth is not the only way bamboo wins over hardwoods, though.
Bamboo can grow on marginal land, not suitable for agriculture or forestry.
On average in a span of 20 years, bamboo produces 12% more material than any woods.
Bamboo has a high elasticity. So it works as a great building material for earthquake-prone regions. It also regenerates quickly even after strong storms.
After cutting bamboo the soil is not exposed to erosion but that happens in clear-cutting of trees. The rhizome mat, which continues to live after each bamboo harvest, protects the ground from erosion.
Bamboo is relatively lightweight because the culms are hollow. So it can be harvested by hand or small chain saws. That means – less fossil fuel is used than by large machinery to harvest trees.
Stronger than steel
Bamboo may look light and fragile, but in case of this material – looks are deceiving.
Research shows the tensile strength of bamboo is 28,000 pounds per square inch. That`s more than steel which measures at 23,000 pounds per square inch.
This incredible strength comes from the fibers which make up the inner and outer skin. The skin is waterproof, thanks to high silica content.
It protects the inner wood from weather and insects. Also, the hardness of the inner wood under the skin is similar to oak.
The structure of bamboo is like a tube with reinforced joints or segments. This natural tubular design results in lighter weight over longer lengths and protects against bending and breaking much better than a steel rod.
Also unlike steel, bamboo is not a heat conductor. It is a great insulator, providing natural cooling and energy efficiency in a building.
Prefered bamboo species for construction
Two of the most popular species of bamboo in the world for construction are:
Guadua bamboo in America
Moso bamboo in Asia
Guadua bamboo (Guadua angustifolia) originates from tropical forests in the Central and South America. Guadua prefers humid habitats of cloud forests and lowland tropical jungles but can withstand cold climate.
Guadua bamboo has a very straight and strong pole, thick-walled, the average diameter is 10-17 centimeters. Guadua grows up to 21 centimeters a day. In the first 5-6 months, Guadua bamboo can reach a maximum height of 30 meters. It can be harvested after 4-5 years.
Guadua is considered to be the world’s strongest bamboo. It has extraordinary load bearing capacity.
Moso bamboo (Phyllostachys pubescens) originates from China. It has an unusual development process.
After planting, for the first 5 years, Moso bamboo doesn’t have any signs of growth. However, like a miracle, it grows up to the height of 70cm per day, even 120cm. Within 40 days, it can reach nearly the height of 30m with a diameter of culm about 18cm.
Moso bamboo is the most valuable bamboo in Asia, especially China, It is one of the most highly used plants for economic activities.
Moso bamboo is used widely in the construction, paper, textile, and wicker industries.