Thursday June 23 2011

Bamboo: A low-cost housing material

Bamboo: A low-cost housing material

A house at Makerere University that is partly made of bamboo. Other bamboo products include chairs and roofing sheets (below left). PHOTOS BY SARAH TUMWEBAZE 

By Sarah Tumwebaze

Today, most materials are expensive and thus every builder and home owner aims at cutting construction costs. There are various low cost materials on the market that can be used. However, the most recent one is bamboo.

Bamboo in construction
It’s not yet popular in Uganda but the few people that have put it to use testify about its cost-effectiveness. At Makerere University, there are two structures that are partly made of bamboo.

According to Engineer Samuel Kapasa, the assistant coordinator of the Bamboo Project at Makerere University, one structure is at the faculty of technology while the other one is next to the Makerere Guest House.

Prof Barnabas Nawangwe the Principal, College of Engineering, Design, Art and Technology at Makerere University, says the two roomed, six square metre bamboo house at the faculty of technology cost USD20,000 (Shs48m).

“The demonstration project was meant to assure people that bamboo is a good and durable material and that beautiful houses can be built using bamboo,” he explains.

Eng Kapasa explains that the bamboo material used on these structures is treated and it was donated to them from International Network for Bamboo and Rattan (INIBAR).

“The headquarters of Inibar are in China and they donated the bamboo materials as a way of introducing modern construction and other bamboo-made home products in Uganda.”

The engineer explains that bamboo has been in use for over 200 years in Asia. However, in Africa, especially in Uganda, it’s not yet popular because people look at it as a material that is used by poor people.

It’s not yet popular, “due to limited knowledge and lack of good species in most of the country. Many people think that bamboo is weak and not suitable for construction of permanent buildings,” Prof. Nawangwe says.

However, Eng Kapasa says that the two structures that were constructed at Makerere have a lifespan of a minimum of 25 years. He adds that in China, the oldest bamboo house was built in 1955 (56 years ago) and it still exists.

Other uses of bamboo
Besides bamboo being a construction material, it has a number of other uses. Other objects made of bamboo include baskets, furniture, blinds, utensils and fences, among others.

Advantages of bamboo
Eng Kapasa says that bamboo is renewable and sustainable. He adds that unlike other wood materials, bamboo is flexible and thus can easily be bent “that’s why it can be used to manufacture a range of products.” He adds that because of the flexibility of bamboo, it can be used without damage. It doesn’t bulge or contract thus making it good for furniture and floors.

The cons
Like any other product made of wood, bamboo is not supposed to get in close contact with water. This means that it cannot be used in the foundation or it cannot be put in places like the kitchen and bathroom. If it is constantly in contact with water for a long time, it will mould with time, become weak and lose its beauty.

Protecting bamboo from insects
According to www.koolbamboo.com, you can either smoke bamboo and heat it so as to preserve it.

“Bamboo can be preserved through smoking. The smoke makes the skin inedible to insects which therefore reduces the chances of the bamboo being eaten up by insects,” it says.

As regards to immersion, freshly cut canes are immersed in water for four to 12 weeks. The nourishment for insects (starch and sugar) is removed. For this, streams are more suitable than stagnant ponds. Saltwater is not suitable though, because the salt will stay in the bamboo and can bring moisture and fungi into the canes.

Treatment of bamboo
According to www.chalet-bamboo.com, the natural durability of bamboo is lower than that of wood and in most cases, it is not long enough for an economic lifetime.

“The lifetime of an untreated bamboo can vary between one and 15 years depending on conditions, for instance, if it is in contact with water and soil, undercover and humidity.

There are both non chemical and chemical methods of preserving bamboo. The non-chemical methods are smoking, heating it over fire and soaking it. However, Eng Kapasa says these are not suitable for lasting protection of bamboo. The other method which is in chemical form is the best.

The website explains that bamboo products are often tanalised by boiling with highly toxic substances such as chromated copper arsenate to protect them against rot. It can also be treated with boric acid and borax which result in the formation of disodium octaborate, which is easily soluble in water. Boron salts are effective against termites and fungi.

Maintenance guide
If bamboo is used for construction, Eng Kapasa advises that you protect it from water, especially if it’s in the raw form. “You will need to put it off the ground to prevent it from rotting which can later weaken the house.”

If it’s used for roofing, it should be covered with transparent iron sheets to protect it from rain water. In cases where it’s used to support the roof, Eng Kapasa advises, “You give the house a big overhanging so that it can limit the water that gets into the bamboo.”

To add beauty to this multi-purpose product, it can be painted and varnished in whichever colour you want.
However, Eng Kapasa says the challenge is that the bamboo in Uganda is not of good quality and it can thus be used sparingly.

“The bamboo materials used to construct houses are imported from China. So, if an individual wanted to use bamboo, they will have to import it which will increase the cost of construction. However, in the near future (three years) Inibar will establish a bamboo processing factory in either Uganda or a neighbouring African country, which will make importation cheaper,” he explains.

Prof Nawangwe says that If the technology is well developed, it is estimated that bamboo will reduce the cost of construction of simple houses by more than 30 per cent.

advertisement