Second in a series
People who build with bamboo are usually true believers, convinced that there is no better construction material on Earth. They cite instances from around the world of multi-story buildings made entirely of bamboo, bridges that support heavy traffic, elegant bamboo hotels and convention halls, buildings that easily withstand earthquakes and hurricanes, and centuries-old bamboo homes as proof that this material, if used correctly, has few limitations.
In addition, they’ll readily cite its economic and environmental advantages: Bamboo grows easily and more quickly than wood in tropical, subtropical and temperate regions around the world; and because it’s lightweight, compact and straight, it’s easy to transport and store. In a carbon-conscious world, the fact that it grows quickly makes it more effective than planting trees at absorbing carbon dioxide and mitigating climate change.
But they’re usually also careful to say that if bamboo isn’t used properly in building, serious problems can arise.
For example, bamboo must be treated with a mild solution of boric acid soon after cutting in order to eliminate the threat from insects, a severe problem with untreated bamboo. The most effective treatment is to apply the solution under pressure to one end of freshly cut bamboo stalks, so that it displaces sap along the entire length of the stalks.
Most builders buy treated bamboo from a few suppliers.
Bamboo used for construction should also be of a species adequate for this use; the most highly recommended for building are bamboos of the genus Guadua, several species of which are native to Central America.
Bamboo is sensitive to water and sunlight, so it’s best to use building designs with features such as wide eaves, which minimize direct exposure of bamboo to these elements. Bamboo also should not be in direct contact with soil because, since it is essentially a hollow tube composed of smaller tubes, it acts as a very effective wick, absorbing moisture quickly along its length, causing it to rot. For this reason, bamboo builders recommend placing bamboo supports on stone or thick concrete bases.
However, once properly treated and maintained (by cleaning and applying a light oil, such as linseed oil), bamboo can last “indefinitely,” according to Martín Coto, one of the most experienced Costa Rican bamboo designers and builders.
Bamboo construction is of basically two types: all-bamboo construction or bamboo used with other materials, such as wood or concrete. In both of these types of construction, bamboo is typically used for the basic structure, joined by steel bolts. Walls can be made from woven bamboo, with or without a coating of cement or stucco. In his home, Coto has built the walls with bamboo lath coated with clay. Coto, an artist at heart, believes that bamboo construction is more attractive when mingled with other materials, and typically works with varied combinations of bamboo, wood, stone, ceramic and concrete.
Perhaps the biggest problem facing the widespread use of bamboo as a building material in Costa Rica is the lack of a developed supply chain to support a bamboo construction industry, which makes building with bamboo more expensive than it should be. This includes not only a lack of sufficient plantation-grown bamboo, but also adequate capacity to process and transport bamboo, as well as workers and builders experienced in its use.
While building with bamboo is still very feasible – at present in Costa Rica a high-quality bamboo building is about equal in cost to conventional concrete construction – Coto estimates that its use would be a fraction of the cost if these elements were in place. One of the most expensive components of building with bamboo in Costa Rica is labor, because bamboo construction requires more time and skill from laborers. For this reason, builders try to pre-cut and assemble as much of a building as possible in their workshops rather than at the site.
An Integrated Solution?
Building permits for bamboo buildings in Costa Rica are readily issued for plans signed by an architect or engineer. Bamboo buildings in Costa Rica are usually custom-designed and built by a designer-builder like Coto or one of several architects familiar with bamboo – often with a strong do-it-yourself contribution from a bamboo-smitten owner.
From Costa Rica’s northern neighbor comes an intriguing effort to completely integrate bamboo construction – growing, treating, processing, transporting and assembling prefabricated bamboo houses in a single process. CO2 Bambú, a private company based in Nicaragua, is aiming to use such a process to offer prefabricated bamboo houses throughout Central America.
CO2 Bambú began as an initiative to provide low-cost bamboo housing to indigenous communities on Nicaragua’s Atlantic coast. After Hurricane Felix devastated villages in the region in 2007, the company worked with relief agencies to build low-cost, weather-resistant homes for several communities. Becoming completely convinced of the advantages of building with bamboo, and finding ideal conditions for growing Guadua bamboo in Nicaragua, the company began searching for ways to expand its operations.
CO2 Bambú’s founder, Ben Sandzer-Bell, a French-American with a background in the aerospace industry, believes that by creating an integrated process to build prefabricated houses in Nicaragua (taking advantage of lower labor costs) and shipping them throughout the region, he has hit on an idea that will make bamboo construction much more common in Central America, help mitigate climate change by using large amounts of fast-growing bamboo, and meet the housing needs of people of all income levels.
An interesting aspect of CO2 Bambú is that it will build houses on what Sandzer-Bell refers to as three levels, or bands: emergency shelters for disaster relief, low-income housing for social development projects, and well-appointed houses for middle- and high-income buyers. For this last market, CO2 Bambú has joined with Bamboo Living, a Hawaii-based company with long experience building luxury bamboo homes. In Costa Rica, the alliance is looking to market these upscale bamboo houses primarily to baby-boomer retirees.
All in all, not bad for a material that, depending on the species, is also great for landscaping, for making paper, furniture and a strong and supple cloth, and that can be eaten.
Bamboo Building Resources
Bamboo Building and Design, treated bamboo for construction
Bamboo and sustainable architecture
Dreaming of Bamboo, Tel. 2710-1958
•Adrian Bonilla: [email protected]
Information and technical resources
•Asociación Costarricense de Bambú: www.acobambu.org
Steve Mack is an environmental consultant who has lived and worked in Costa Rica for over 20 years, and is a partner in the firm Responsabilidad Ambiental Corporativa. He can be reached at [email protected].