The construction sector is a sector with a significant environmental impact. At the same time, it is a sector that faces significant challenges: how can we continue to provide suitable buildings and a pleasant living environment, with a growing world population and changing housing- and work preferences? This, along with other challenges, requires adaptation and development of the global construction sector. The path towards a sustainable construction sector is already being explored by various clients and contractors, and there are still many opportunities for future innovations. In this article, you will get an introduction to why sustainable construction is important and what it can look like in practice.
Why is sustainable construction important?
The global construction sector and the built environment are responsible for a significant share of the total human-induced greenhouse gas emissions. Building-related energy consumption, and the CO₂ emissions produced during the manufacturing of construction materials, together account for a quarter (26%) of all human-induced greenhouse gas emissions.
In particular, the production of traditional building materials such as concrete, steel, aluminum, bricks, and plastics has a significant impact on the climate. Construction projects also have a significant impact due to all the transportation associated with the construction site, including materials, machinery, and workers, etc.
With a growing world population, the need for (new) construction is not diminishing. However, traditional construction methods are becoming increasingly burdensome on the climate. Therefore, there is a need for sustainable forms of construction, that allow us to continue executing construction projects in the future. In addition, the existing housing stock requires sustainability improvements to save valuable energy. This, too, is a major challenge.
© Daria Scagliola & Stijn Brakkee
What is biobased construction?
The materials you use for construction largely determine how sustainable your construction is.
We can distinguish between biotic and abiotic materials:
- Biotic materials are living, renewable materials derived from nature. Another term for this is "biobased." Wood is an example of a biotic material.
- Abiotic materials are non-living, non-renewable materials produced by humans. Concrete is an example of an abiotic material.
Since the industrial revolution, humans have increasingly replaced biotic materials with abiotic materials. The production of these abiotic materials requires fossil fuels, and results in significant CO₂ and other greenhouse gas emissions. These emissions are enormous: approximately 14% of all human-induced emissions come from the production of concrete and steel. This share is so high because these materials are produced at high temperatures (sometimes above 1500 degrees Celsius), leading to high energy consumption and associated CO₂ emissions. Global emissions related to concrete are even higher than those of the global aviation sector!
On the other hand, biobased materials do not cause massive CO₂ emissions. In fact, many biobased materials even sequester CO₂ during their lifespan. Think of trees, which absorb CO₂ from the air and convert it into material to grow. The same applies to, for example, the hemp plant and various types of grasses.
Other benefits of biobased construction
Biobased materials are much lighter than many abiotic materials. For example, (soft)wood is almost five times lighter than concrete (500 kg/m³ compared to 2400 kg/m³), and much lighter than steel (7900 kg/m³) or aluminum (2700 kg/m³). This significantly reduces transportation costs; transporting a cubic meter of wood requires much less (fossil) fuel than a cubic meter of concrete or steel. This is another reason why biobased materials are a good choice for sustainable construction.
The fact that wood and other biobased materials are much lighter than traditional abiotic materials, also has architectural implications. Because buildings have less weight to support, less material is needed for load-bearing structures overall. This is another characteristic of biobased materials that reduces their impact on the climate compared to heavy, non-biobased buildings.
Biobased materials are also well-suited for modular and circular construction. Wood is easy to work with, and window/door shapes are easy to cut into it, and you can easily create prefab elements. These elements can then be easily assembled and disassembled, and the parts can find new applications elsewhere. Elements can be effectively reused, and if full reuse is not possible, the material can be repurposed for other applications.
Biobased materials are supplied by nature, and continually replenish themselves. With good management and planning, there is no end to the possible use of these materials. In the case of abiotic materials, the situation is different; not only are fossil fuels running out, which are needed to produce these materials, but also the raw materials from which these materials are originally made.
Source: https://edition.cnn.com/style/worlds-largest-wood-city-to-be-built-in-stockholm/index.html
Wood is an example of a biobased material with tremendous potential that is already being used in various new construction projects. For example, the swimming pool complex for the Olympic Games in Paris is largely constructed in timber, with sustainability and repurposing integrated into the design. In Stockholm, Sweden, the world's largest wooden residential neighborhood is currently under construction.
Closer to home, there is also a strong focus on timber construction. In the metropolitan region of Amsterdam (MRA), the Green Deal Covenant Houtbouw was established, with the goal of having 20% of all newly constructed homes made of wood (and other biobased materials) by 2025. This will result in an annual savings of approximately 220,000 tons of CO₂ emissions and a significant reduction in nitrogen emissions.
Many of these wood construction projects are currently under construction or have already been partially completed. If you want to know where these projects are located, you can check the Locatie Monitor.
Myths about timber construction
But not everyone is completely convinced yet, of the role that timber can play in a transition to sustainable construction. Often, unwarranted assumptions are made about the properties and possibilities of timber constructions. Many people are concerned about factors such as the fire resistance of wooden buildings, the lifespan of wooden buildings, or the durability of the structures. However, wood is a building material that, in almost every respect, is as capable as traditional materials like concrete and steel.
Imme Groet, Senior Sustainable Construction Expert: ."You often hear people say timber construction is too expensive. But even this is changing significantly in the current market; timber construction is almost as cost-competitive as other construction methods. Furthermore, experience with timber construction is growing, so all parties can -and will be able to- work well with this very promising material."
Discover all the unfounded myths about wood construction in the Booklet "Discussing Timber Myths: a dialogue between our ambitions and the facts" - AMS Institute for advanced metropolitan solutions.
Source: De Houtbouw Revolutie. Op weg naar een circulaire toekomst.
Pablo van der Lugt & Atto Harstra. Material District, 2021
