Wednesday, October 5

Replacing steel and concrete with wood?



As mentioned in the previous article, the building materials used in urban construction emit large amounts of greenhouse gases during the production process and increase the risk of air and water pollution. Currently, cement and steel still account for 80% of the raw materials used in construction.

The United Nations expects the number of people living in cities to rise from more than half of today to nearly 70% by 2050. Under the pressure of coping with global climate change, urban construction and planning will face incredible challenges. Cities need to be greener, more comfortable, and more cost-effective than ever.

Environmental effects of wood use

Partial replacement of cement and steel with wood may be a feasible solution. Wood has a wide range of uses in civil engineering. In addition to house building, it can also be used in building bridges, sidewalks, guardrails, and noise barriers.

Japanese researchers found that by increasing the use of wood in construction, furniture, and energy production in Japan, the greenhouse gas emission reduction potential can reach a maximum of 9.6 million tons per year in 2050, which is close to 1% of Japan’s current annual emissions.

The most significant effect is replacing high-emission and high-polluting cement and steel with wood products. The share of emission reductions comes mainly from the carbon storage in wood products (73%) and material substitution (19%). The remainder comes from partially replacing fossil products such as coal as fuel (8%) with recycled waste wood and forestry residues.

Beyond emissions, using wood instead of other building materials is expected to save Japan a staggering 350 billion JPY in the costs of dealing with health and environmental pollution issues.

Health benefits of wooden buildings

Several studies have shown that increasing the use of wood in the home and office can help improve overall health. Some cases show that working in wooden buildings can improve employee job satisfaction and job performance. This effect may be due to the better environmental quality of the interior with the presence of wood.

Wood has biophilic properties, and humans have an innate need to connect with nature. People generally like the feel of wood by seeing, smelling, and touching it. When surrounded by wood structure, neurological, physical and psychological responses may help us reduce stress, lower blood pressure, make mood positive and increase focus.

Cultural significance of wooden architecture

Wooden buildings have special cultural significance around the world. Wood has been used for houses since ancient times.The oldest surviving wooden structure in the world is Horyu-ji Temple in Japan, which was built in the early 7th century. The preservation and inheritance of Japanese wooden architecture lie in a traditional set of skills, techniques and knowledge. Artisans of different skills must work together to maintain and restore traditional wooden buildings. By promoting cooperation and social cohesion, traditional wooden buildings have their specific social function and reinforce Japanese cultural identity. To date, many Japanese houses still use traditional wooden structures in many aspects.

In densely forested Borneo, wooden longhouses are deemed one of the oldest permanent structures on the island. Longhouses are deeply rooted in local culture, and the architectural form incorporates many of Borneo’s traditions and values. The gradual disappearance of longhouses also represents a trend toward the disappearance of traditional Borneo customs. Reusing wood and incorporating various longhouse elements in modern architecture may provide a new way to revitalise traditional values ​​and identity.

Longhouses are deeply rooted in local culture, and the architectural form incorporates many of Borneo’s traditions and values. (Image credit: Henry Ling Roth, public domain, Wikimedia Commons)

Promotion of wooden construction

The promotion of wooden buildings may start with public buildings in cities. In city-building, the public sector is often the largest customer of the construction industry. Governments may consciously increase the proportion of wood in building materials for projects like schools, social housing, libraries, and medical centres, to demonstrate the benefits of various wood structures and promote the transformation of the entire construction industry. There is a law in Japan that requires construction companies to use wood for public buildings below three storeys high.

Governments may also promote wood construction through various educational and advocacy channels to demonstrate the benefits of wood use. In Borneo, an interesting example is the Murut Cultural Centre in Sabah. Its design and construction are based on traditional Murut longhouses, with the central column made from 207 logs of Borneo Ironwood (locally known as Belian), one of the hardest woods in Southeast Asia. Currently, the Murut Cultural Centre is the largest ironwood building in Borneo.

Potential drawbacks of large-scalewood use

In tropical regions like Southeast Asia, nesting insects, termite infestations, mold, and various forms of decay are all frequent problems with wooden buildings due to the hot and humid climate. If wood is used, the building has to be specially treated to ensure that these problems do not arise. Maintenance work must also be carried out frequently.

Also, a rapid transition to heavy use of wood may put enormous pressure on forests if not appropriately handled. While it is true that reducing the use of cement and steel can reduce negative environmental impacts, increasing wood consumption will also increase the risk of overexploiting forests. This risk is particularly sensitive for Borneo, which has long suffered from the negative impacts of land-use change. Therefore, it is necessary for the authorities to strictly implement sustainable forest management with selective harvesting and replanting in order to minimise the pressure on the forest.

Using wood to partly replace cement and steel remains an exciting solution to address the climate impacts of city-building. If appropriate strategies can be developed and carefully executed, it is possible to achieve substantial emission reduction. City planners, the wood industry and those in the construction sector will play a key role here.

Southeast Asia’s megacities have been constantly changing and adapting to new technologies and environments for the past few decades. It is not impossible to bring sustainable architecture to new heights by adopting wooden structures, potentially with traditional and cultural elements, in order to combat climate change and also to restore heritage.

Dr Goh Chun Sheng is a researcher at Sunway University and Harvard University. His research interests lie within the intersection of bio-economy development and environmental restoration, with a special focus on both Malaysian and Indonesian Borneo.