Green Construction in Focus: Lightweight Building Materials

30thMarch 2021
Green Construction in Focus: Lightweight Building Materials

Whether you are an environmental sceptic or not, the truth is, the building industry is evolving and environmentalism and protection of the environment has become a red hot topic. With traditional building processes, many materials have harsh impact on the earth’s natural resources and the environment. With a growing push by governments and industry bodies around the world, the construction is seeing a shift to employ sustainable materials that help protect the environment in the long run.
In this piece, we deep dive into the changes which are afoot and take a look at various lightweight construction materials being used in the building industry today and how the utilisation of these improves your project and limits the effect on the environment.

What are eco-friendly building materials?

Eco-friendly building materials are those that either do not harm the environment or limit their impact upon it (both in their development and in their final use), created through the efficient utilisation of renewable resources, as well as the nominal use of energy and natural resources in making them and while using them.
In Australia, the use of environmental-friendly construction elements is governed by the Green Building Council Australia or GBCA which aims to

“… achieve more productive, liveable, sustainable and healthy cities; secure more resilient communities; deliver a low carbon, high performing built environment; raise minimum standards through the National Construction Code; and facilitate sustainable utility infrastructure.”

Recognising that the construction industry generates forty per cent of waste, consumes around a third of Australia’s water, and remains the number one contributor to greenhouse gas emissions, the GBCA aims to assess “… sustainable design, construction and operation of buildings, fitouts and communities …” through its Green Star initiative.

Why are Green Star buildings better for our environment?

According to the GBCA, Green Star buildings not only help promote the overall well-being of occupants but also:

  • produce 62 percent fewer greenhouse gas emissions than average Australian buildings;
  • consume 51 per cent less potable water than minimum industry standard;
  • use 66 percent less electricity than average Australian buildings; and
  • recycle 96 per cent of their construction and demolition waste.

These figures alone showcase the valuable input Green Buildings can have on the future of our planet, but there are many more benefits as well. If you are looking to build sustainable and more green buildings to contribute to the creation of more liveable communities around the country, you can start by opting for low-impact materials in your construction venture. Below are some of the lightweight construction materials that you can consider.

Recycled Steel

Steel remains one of the most recycled materials in the world, with a 95 per cent overall recycling rate in Australia, which is classified as one of the best in the world.
When steel is recycled, it spares thousands of pounds of iron ore, coal, and limestone from being used. The reproduction of steel also saves energy; with some estimates stating enough power for a total of around 20 million houses a year could be saved.
Whilst there are arguments that cuildings made of steel lower longer term impacts on the environment as they are not easily affected by weather elements and are resistant to infestations of insects and mould, consideration must be given to the entire picture. Sure, unlike wood, steel – if coated with intumescents, can resist fire for longer – and as steel delivered onsite is pre-customised according to the specifications required by the builders, little waste is produced, but what is the carbon footprint of getting to that stage?

Lightweight Concrete Blocks

Lightweight concrete blocks are construction materials made of cement mixed with aggregates like pumice, foamed slag, shales and clays, or even fuel ash aggregate. They are often used to insulate roofs and water pipes and even as partition walls inside buildings.
Lightweight concrete blocks have low thermal conductivity, making them a safe choice for improving the fire safety protection of buildings. Because heat transfer is slow in this type of material, you can also lessen the energy consumption used the structure, thus minimising the greenhouse gas emissions from the building.
Lightweight concrete is highly durable, especially when properly cured. It becomes more elastic, stronger, and thus help in reducing shrinkage and cracks as a result of pressure, chemical attack, or physical stress.
Although a less obvious environmental benefit, transportation of lightweight concrete blocks can help reduce transport impacts and the release of carbon footprints to the atmosphere because more materials can be loaded in one load unlike heavier structural materials which when transported are only limited to fewer volumes per trip.

Plant-Based Polyurethane Rigid Foam

One of the most popular materials used for insulation of wall assemblies and roofing is rigid foam. With its strength, easy installation, and water and pest resistance, it makes a great choice in making a building more energy efficient as well as more comfortable for occupants.
A new technology in insulation product making has allowed the utilisation of bamboo, hemp or kelp to make plant-based polyurethane rigid foams. With this, you can expect a higher level of resistance from mould, insects, as well as moisture, thus ensuring a long life cycle and eliminating the need to replace it prematurely. Plant-based rigid foams are not only lightweight but are also have a great high-heat resistance, aiding in the maintenance of a cool indoor temperature and decreasing the energy required to cool a building.

Cross-laminated Timbers

Like the name would suggest, Cross Laminated Timbers (popularly called CLT) refers to a plywood made of boards that can reach enormous dimensions: between 2.40 m and 4.00 m high, and up to 12.00 meters long. Each alternate layer is laid with the grain at 90 degrees to the prior one, making it a matrix formation. The wood is adhered with resins thus further enhancing the strength of the wood.
Made from either recycled timbers, or more often from timbers from sustainable forests, CLT represents a viable green building material. Adding to its credentials is the fact that the environmental impact from production is a fraction that of concrete and steel. Try this fact on for size: One tonne of Carbon Dioxide is emitted for every cubic meter of concrete produced, whereas CLT contains “sequestered carbon,” or carbon that is naturally stored in wood during tree growth.
And if you need any further proof that CLT is a lightweight material of the future, consider this, when comparing CLT and concrete, to achieve the same degree of insulation that a 100 mm thick CLT wall would provide, you would need to build a concrete wall with a thickness of 1.80 m. (1/18 ratio).
For more on why CLT is an amazing construction material, read an article on it.

How to Find Lightweight, Ecologically Friendly Building Materials

Aside from the materials mentioned above, there are many other construction materials that forward-thinking builders are starting to use which improve construction, enhance architectural elements and which assist in protecting the environment.
The next 10 years in construction are going to be exciting and transformative, so the sooner you start to make a change, the more you will keep up with the industry.


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