Explore Energy

When it comes to constructing a new home, many of us want to reduce any impact to the environment as much as we can.

By building with sustainably sourced materials and taking sustainable design principles into consideration, you can build harmoniously with nature and add value to your home.

Happily, there’s a variety of sustainable building materials to choose from if you want to go down this path. In this guide, we’ll cover options both ancient and modern options for you to explore so that you can build a more sustainable home for the future.

What are sustainable building materials?

Building materials have to fulfil a number of criteria before they can be classed as sustainable, based on State Government guidelines:1

  • sourced from renewable sources
  • be recyclable or reusable
  • use as little water as possible to manufacture or construct
  • low maintenance after construction
  • provide good insulation to the finished building
  • offer suitable structural properties for the application.

In short, it must have a minimal impact on the environment over the course of its life.

Traditional sustainable building materials

For most of human history, these sustainable house materials have been used to construct homes and continue to be an option for new builds today.

Timber

a timber weatherboard house undergoing construction

ProsCons
  • Highly renewable building material
  • Low environmental impact
  • Low cost
  • Requires additional insulation
  • Needs maintenance
  • Less fire resistant than other materials

Timber is a renewable resource and can be readily sourced from sustainably managed forests and plantations. It’s light and easy to work with for builders and requires minimal specialist equipment beyond standard carpentry tools. It also has a very low environmental impact when it comes to the energy used to turn it into a usable material (known as embodied energy).2

The major drawbacks are that it deteriorates over time if not carefully maintained by staining, oiling or painting (which takes time, effort and money).3 Additionally, sustainability Victoria notes that most weatherboard homes built before 1990 don’t have insulated walls – this means they can get very cold in winter, and hot in summer.4

Of course, you can add insulation to a timber home after the fact when renovating, and when building a new home, it’s easy to include insulation when building.

Timber can also be used for edging parts of the garden path, roofing, retaining walls, footpaths and other aspects of the home. Depending on the specific element of the home, you may be able to use reclaimed wood and recycle materials from a previous building – further reducing any environmental impact from your home.

Brick, clay and concrete

a modern brick and concrete home

ProsCons
  • Reclaimed bricks reduce environmental impact
  • Sturdy and long-lasting
  • New bricks are less environmentally friendly
  • Costlier than other traditional sustainable materials

Bricks come from a non-renewable source, as clay is dug out of large pits and fired into bricks, while the components for concrete bricks are also mined in various ways. However, they are reusable – should a building be demolished, the bricks can be cleaned and reused as new building material or paving.

The longevity of brick buildings is much greater than timber. While there are some issues with the thermal properties of brick veneer buildings in summer, double brick or ‘cavity brick’ buildings have excellent insulating properties during winter.5

It’s also worth considering roof tiles such as terracotta or clay or even slate (cut stone).  Slate is heavy, relatively fragile and often imported. Even clay tiles have a considerable amount of energy involved in their creation and they may have plastics mixed-in.

However, you may be able to recycle roof tiles or look for locally made tiles with as few plastic components involved as possible.

Mud brick

a mud brick house in the Outback

ProsCons
  • Low environmental impact
  • Affordable and readily available construction material
  • Specialised knowledge and training required from builders
  • Building approval process is more complicated

A classic sustainable building material that’s been around for thousands of years, mud bricks are generally constructed onsite using available soil. This style of home is also known as ‘Adobe’ in some parts of the world.

The low energy inputs for material transport and construction make mud bricks an attractive option for those wanting sustainable building material, as they’re formed and dried using only natural energy from the sun and wind.

However, mud brick (and earth walls) have a more complicated building approval process as the Building Code of Australia is undergoing an update and the current version no longer mentions earth wall construction. The South Australian Government encourages anyone interested in using mud brick to contact a structural engineer or expert builder for advice.6

Rammed earth

a rammed earth wall with a doorway

ProsCons
  • Easy to use material
  • Affordable and easily accessible
  • Improved insulation
  • Limited amount of shapes that can be achieved
  • Experience and specialisation required when mixing soils

A variation on mud bricks, rammed earth uses onsite soil mixed with gravel, sand that is poured into a wooden or metal temporary frame, known as the ‘formwork’, and pounded into solid walls. Once set the formwork can be taken away.

The Earth Building Association of Australia notes that it is easy to mould and shape, with the only limit being the formwork frame.7

Another type of rammed earth construction is known as cob construction. It uses straw as well as soil, gravel and sand, but no formwork frame. The use of straw helps improve insulation, but the lack of a frame means the walls are typically smaller and less dense.8

Straw bale

a straw bale house with corrugated roof and wooden patio

ProsCons
  • Affordable building material
  • Low environmental impact
  • Requires maintenance
  • More susceptible to pests and mould

Like the name says, straw bale construction uses bales of hay or straw-like giant bricks to build walls. The walls are then covered with a render to prevent moisture from entering and rotting away the straw. This also stops potential fire hazards and keeps vermin out of the straw where they could otherwise nest and cause structural integrity problems.

Straw bale buildings generally have good thermal insulation. The bales of straw themselves can be load bearing, but in places that receive snow or extreme weather, the home can be built on stronger supports and use the straw bales to fill in the walls and provide insulation.9

One key downside is that the plaster which protects the straw can crack and will need to be maintained to prevent mildew, pests damage and to ensure the home is resistant to fire.

Straw can even be used to make thatched roofs, though this is very rare in Australia due to the risk of bushfires, mould, and pests making themselves at home in the roof.

You’re more likely to see grass roofing on small gazebos and huts by the pool to add a ‘tropical feel’ to a home, rather than as a roofing material.

Modern sustainable building materials

Beyond traditional resources are more modern green building materials. Some, like steel and concrete, have become more mainstream in the last century, while others are more innovative solutions to improving a building’s sustainability.

Steel and concrete

shadows falling on a concrete and steel house interior

ProsCons
  • Strong and sturdy material
  • Long lasting
  • Less environmentally friendly
  • More costly than other materials

The increasing use of steel and concrete in construction is primarily an economic one. Materials can be purchased in bulk and used on any project of pretty much any size.

The most common way to use these materials is by pouring concrete around steel reinforcing mesh in a frame, then attaching the formed walls to a steel framework. This may be done onsite, or prefabricated concrete panels can be transported from a manufacturing plant.

Concrete is really good at retaining heat from daylight. While this will be good in winter and cool nights, it can be an issue if you have a concrete floor exposed to the sun in summer. Sustainability Victoria recommends using concrete floors in homes that are north-facing, as this orientation naturally reduces the harsh impact of summer sun while keeping the house well-lit and warm in winter.10

Steel and concrete are also commonly used for roofing with concrete tiles and metal sheet roofing. Metal roofing is less environmentally friendly than clay tiles, but not by a lot. This is because the thin size of the metal compared to thicker clay tiles means you need less material to cover the same amount of area.

Other products

There are numerous specific building products available, including specially designed materials that behave like brick or concrete but have enhanced thermal insulation properties. They include materials manufactured using wood waste, recycled glass bottles, polystyrene, or even aerated concrete, manufactured using various industrial processes.

The sustainability of these building materials varies, so each material should be considered individually.

It’s also worth noting that the type of material you use can affect the value of your home, which in turn affects the cost of your home and contents insurance.

How different building materials can affect your insurance

a construction worker building a wooden house frame

Whether you go completely modern, solely traditional, or a mix in-between, the type of construction materials you use can affect the cost of your home insurance. This is based on the cost of the materials used and how much it would cost to repair or rebuild, plus the sturdiness and weather resistance of the structure.

Learn more about what affects the cost of home and contents insurance here.

How to improve the sustainability of your building

a tree house in the forest

Deciding which building material you want to use will essentially boil down to three factors:

  1. environmental factors: it’s up to you to determine how far you’ll go to make your home sustainable – will you only use eco-friendly building materials or will you use a mix of materials to help reduce the building’s environmental impact?
  2. economic factors: some eco-friendly building materials are cheaper than others, but they might also need more upkeep and maintenance at times.
  3. comfort factors: personal preference will also play a role in selecting construction materials. A concrete building may be cheaper and longer-lasting, but people may prefer an older-style wooden house to a concrete box.

Besides the construction materials, there are many other ways to ensure your home is as environmentally friendly as possible. Such additions can also reduce your energy bills, after some initial investment on your part.

Passive solar and cooling design

a modern house

During summer the sun shines down from east to west at a higher angle, beating down below.11 For this reason, the city council of Joondalup in Western Australia notes that there are a range of building designs choices that can be built-in to make a difference:

  • have living spaces in the northern side of the building, as that area is most comfortable all-year round
  • have smaller windows with shaded blinds on the east and west of the house to help protect against hot summer sun
  • the roof can overhang on the east and west to help block out high-angle sun during the heat of the day
  • north-facing windows can be bigger to allow low-angle winter sun in to warm the house – though shades might be necessary for summertime12

Your location within Australia can make a difference based on the angle of the sun and general temperature experienced across the four seasons. Also, you might have natural breezes that you can take advantage of.13

Catching solar energy

a house with solar panels on the roof

Photovoltaic panels (PV) solar panels and batteries or solar hot water systems can significantly reduce reliance on non-renewable energy sources. The initial outlay for solar panels may be relatively high, but solar systems will pay for themselves over time. A good solar hot water system can save energy too by heating water when the sun is available, and storing it in a battery pack for use later on.

Using rainwater tanks

a water tank attached to a house

Harvesting rainwater can be beneficial, especially if you use it to water a vegetable garden. It can save you some expense in the long term and reduce your reliance on the water supplied by the city, and provide a backup source of water during emergency situations.

There are various sizes and options to choose from, but there are some common maintenance tips as noted by the Brisbane city council:

  • keep the roof, gutters and downpipes clear of obstruction
  • check regularly for leaks
  • seal the tank with mosquito-proof screens to stop mosquitos breeding14

Water storage does have drawbacks – all water catchment needs to be accounted for.

For example, storm water drains are calculated to operate with a certain flow-through of water each year, with a particular peak flow that cleans them out once in a while.15 If water is taken out of the system before it reaches the storm drains, cleaning them out may mean someone has to get in there and do it.

In some cases, water companies will continue to charge fees for this kind of service even if you don’t buy your water from them. It’s worth checking into with water supply companies and city councils in your local area.

Green roofs and walls

a green roof on a home

Green walls and roofs refer to gardens covering the roofs and walls of your building. The NSW Department of Planning, Industry and Environment notes that green walls have a range of benefits:

  • they can cool the air
  • provide insulation
  • block out sound
  • create additional gardening space
  • improve the efficiency of solar panels
  • reduce local flooding16

Geothermal heat pumps

a 3D illustration of a home with a geothermal heat pump

Also known as ground source heat pumps, geothermal heat pumps offer a more environmentally friendly heating option that reduces energy usage, making the home more sustainable. Geothermal heat pumps work by harnessing the heat underground through pipes connected to the heat pump that draws heat up from below the earth’s surface.17

Geothermal heat pumps can also be used to help cool the home too by using colder temperatures under the ground during hot days.

While they do cost more to install than other heating and cooling systems, geothermal heat pumps can help reduce electricity usage and have lower ongoing maintenance costs.

Growing your own vegetable garden

a woman and daughter picking vegetables in a garden

If you have a ‘green thumb’ and love to garden (or even if you don’t), growing your own vegetables at home can further improve your home’s sustainability. You put the soil to use and become more self-reliant and need to buy less food from the supermarket.

Not only does this help save you money but growing your own veggies can help reduce your family’s impact on the environment. This is because there is a lot of long-distance shipping involved in supplying supermarkets with fresh produce, which involves fossil fuels.

Finally, ask questions

When trying to source sustainable building materials for new buildings, or retrofitting old ones, the key is to keep asking questions. If you’re serious about sustainability, always find out where your materials come from, how they’re produced, how long they’ll last and what happens to them when they need to be replaced.

Perhaps most importantly, find a qualified builder you trust who is open to your feedback, just as you are open to theirs. Sometimes what appears to be a more expensive option in the short term becomes a better investment down the track.

One of the big motivating factors to build sustainably in today’s market is to approach energy use judiciously. Part of this process is to select an energy provider with competitive prices. Rather than sticking with a known entity or default provider, shop around and look at the finer detail of what’s available.

Need a place to start your search? Compare energy providers today with us for free – you’ll get to weigh up usage and supply charges, tariff types, discounts and more; all in the one place.

Sources

  1. Environmentally sustainable Building Materials – Selection. Department of Planning, Transport and Infrastructure, Government of South Australia. 2017.
  2. Environmentally Sustainable Building Materials – Selection. Department of Planning, Transport and Infrastructure, Government of South Australia. 2017.
  3. Chapter 6: Materials. U.S. Department of Energy, Government of the United States of America. 2013.
  4. Insulate weatherboard walls. Sustainability Victoria, Victorian Government. 2020.
  5. The double-brick house. Sustainability Victoria, Victorian Government. 2020.
  6. Earth wall construction issues. South Australian Government. 2020.
  7. Earth Building. Earth Building Association of Australia. 2021.
  8. Outside the Box, not Out-of-the-Box. Gayle Borst, Design Build Live. 2017.
  9. Can you really build a house with straw? Library of Congress, Government of the United States of America. 2019.
  10. The estate-style house. Sustainability Victoria, Victorian Government. 2020.
  11. Passive design in site and subdivision planning. City of Wodonga. 2021.
  12. Thing Green Energy: Passive Solar Design. City of Joondalup. 2020.
  13. Powering your new house for less – sustainable housing. Department of Mines, Industry Regulation and Safety, Government of Western Australia. 2019.
  14. Using your rainwater tank. Brisbane City council. 2019.
  15. Stormwater. Your Home, Department of Industry, Science, Energy and Resources. Australian Government. 2013.
  16. Green roofs and walls for nature. NSW Department of Planning, Industry and Environment, New South Wales Government. 2019.
  17. Answer to sustainable heating and cooling beneath our feet? ARENAWIRE, Australian Renewable Energy Agency, Australian Government. 2019.

Ready to look for a better deal? It’s easy to compare with us.

Compare energy plans
Or call us on1800 990 003