Which building construction materials are environmentally friendly?
In the current climate crisis scenario, thinking about an architectural project without defining ecological benchmarks has become practically unacceptable. One of the main emitters of carbon dioxide and other pollutants, the construction sector is increasingly looking for new ways and means that can make works more sustainable and, in some way, mitigate damage to the environment. Thinking about ecological materials can be one of the fundamental steps, but what materials are they?
By definition, to be considered ecological, a material must meet certain general characteristics such as: be made from a raw material that is rapidly renewed, or that is recyclable, biodegradable or capable of being transformed into carbon; their collection, extraction and manufacture must be done locally, avoiding long-distance travel; its inputs must be grown or harvested organically or sustainably and must be free of toxins; and be durable, easy to maintain and easy to reuse. Below you will find some of the materials that meet these requirements:
Adobe and Rammed Earth
Composed of raw earth, water, straw and, in some cases, other natural fibres, adobe is an ancient technique used all over the world. It is a low impact material that is produced manually, does not use fossil fuels in its production and does not require energy to burn it. Thus, the traditional material makes it possible to return its rubble directly to the earth. Other advantages are its low cost, ease of production and implementation.
When adopting the material, it is necessary to pay particular attention to a thorough understanding of the climate and the place where the structure will be built, since it is not suitable for seismic zones and must not be exposed to large quantities. rain, being necessary think about the protection of its surfaces against rainwater or runoff.
Because they have similar materials, many people may confuse adobe with clay, the main difference is in the technique adopted to design the product. While the former is a sun-baked brick and its construction process follows the shape of masonry, the latter normally consists of two parallel wooden panels or sheets of plywood, filled with a layer of moist earth. Once this small layer is added, it is compressed to about half of its original volume by a pneumatic rammer. This process is repeated iteratively until the structure is filled with compacted earth, allowing the timber to be removed and a freestanding rammed earth wall remaining.
If we had to design the ideal building material, it would look a lot like bamboo. The ancient plant, widely used in Southeast Asia, has become increasingly popular in other territories due to its characteristics and advantages, including low cost, easy handling and low energy consumption for its preparation. The material that captures and stores carbon dioxide has demonstrated in laboratory tests that it achieves impressive structural capabilities. Its compressive strength is equivalent to that of concrete, while its tensile strength reaches the figures of steel.
But it must be remembered that all this can vary depending on the species, which are more than 1500 and grow naturally on almost all continents, especially in regions with higher temperatures. In addition, its installation requires unskilled labor. It must receive adequate treatment for protection against pests, as well as it must not be in direct contact with the ground or rain.
Certified or planted wood
Many people still wonder: is the use of wood in architecture sustainable? As it is a renewable material, it is therefore possible to use it without further harm to the environment as long as its extraction rate allows the restoration of the forest and keeps the whole cycle sustainable. To guarantee this, there are different labels that verify the wood and guarantee its quality, such as the FSC (Forest Stewardship Council) and the Brazilian forest certification system INMETRO (Cerflor).
Already a traditional building material, wood is able to store around one ton of carbon dioxide per cubic meter. In addition, its easy handling allows the construction site to be more efficient, reducing construction time and consuming less energy for the construction of structures.
Known as compressed earth blocks, eco-bricks are modular and can be used for structural purposes – replacing other materials that are more harmful to the environment, such as concrete. They are made of earth and cement and hardened with water. In other words, they don’t need any type of combustion. Due to their texture, they can be kept in their exposed shapes, making coatings unnecessary.
By adopting it, we save 70% in concrete and mortar, and 50% in steel, in construction. Its advantages, in general, reduce the construction time by 30% compared to traditional masonry, it makes the construction site cleaner because it reduces the waste of the works and, finally, they can have the pipe embedded in their holes.