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3 Recycled Materials used to Build Sustainable Homes


You would have never imagined the amount of construction products that are manufactured from recycled materials nowadays. As our planet is facing its most devastating years of the effects of Global Warming, it is no surprise that we are littered with rubbish everywhere. We are producing more and more products than ever to satisfy the needs and wants of our increasing global population and as a result, our landfills are overflowing with rubbish and our atmosphere are polluted with greenhouse gases. It is these environmental effects that have inspired scientists and experts to implemented solutions and alternatives to help mitigate its impact on the environment. One solution in place is the recycle and reuse of rubbish such as plastic, by products etc. to produce “environmentally friendly products”. In the construction industry, environmentally friendly products are increasingly popular and are readily available. In this article, I will discuss three recycled ‘environmentally friendly products’ that are in use in construction today with the hope of increasing approval from future builders, clients, and contractors.

Geopolymer Concrete (Eco - friendly Concrete)

Concrete is the most sought after material used in construction since it was first discovered thousands of years ago. The annual global production of concrete is estimated at around 100 billion tonnes (Columbia University, Christian Meyer). Concrete is the finished product from the mixture of raw materials consisting of cement binder (Ordinary Portland Cement), aggregates (sand & gravel), and water. It is estimated that the annual global emission of Carbon Dioxide (CO2) from the cement industries contribute around 40% of the total CO2 pollution in the atmosphere.

In the past centuries, scientists have researched for an alternative material that could substitute the traditional Ordinary Portland Cement Concrete (OPCC) but obtain similar properties to OPCC in terms of strength, affordability, and availability with minimal carbon foot print. It was in the 1950’s that geopolymer concrete was first discovered by Russian scientists. In the late 1970’s the French scientist Joseph Davidovits renewed focus on geopolymer concrete produced successful outcome that paved the way for global production of geopolymer concrete as an alternative construction material to OPCC.

Geopolymer concrete or Eco friendly concrete is produced from the mixture of flyash, slag, alkaline activators and water. Flyash is a by-product of coal combustion in power plants and slag is a by-product of steel production, both recycled materials. The alkaline activator is a combination of solutions of alkali silicates and hydroxides. The mechanical properties of geopolymer concrete are either similar or better that OPCC. The concrete strength after 24hrs have been found to be more than 25MPa with better fire resistance than OPCC [1] and lower drying shrinkage and higher flexural tensile strength. [2]

Australia is well known for its contribution to the geopolymer concrete industry by establishing the world’s first geopolymer concrete structural building with the construction of the University of Queensland’s Global Change Institute (GCI), consisting of four storeys available for public use. “GCI was awarded the Green Building Council of Australia’s 6 Star Green Star rating and ranked 34th in the world’s 50 most impressive environmentally friendly university buildings” [3].

A main supplier of geopolymer concrete locally here in Australia is ‘Wagners’ a family owned company based in Toowoomba Queensland. Wagners is known worldwide for producing and supplying the world’s largest modern geopolymer concrete project containing absolutely no Portland cement for the aircraft pavements at Wellcamp Airport in Toowoomba. The total area of Earth Friendly Concrete (EFC) (Wagner’s product name for geopolymer concrete) covered 50,500m2 and it is believed that the use of EFC instead of conventional concrete reduced CO2 emissions by 6,600 tonnes across the project. [4]

Recycled Second Hand Bricks

Recycled bricks have been quite a popular product in the construction industry here in Australia for the past few decades. Scavenged bricks from demolition sites are recycled and sold at a much cheaper price than new bricks. These bricks are used as home features for character homes or for green building purposes.

A lot of companies supply recycled bricks here in Australia with even a few companies going the full extent of categorizing the brand name of the bricks. One company known to the market is ‘The Brick Pit’. This company have different classifications of bricks with prices installed for each type of bricks. The Brick Pit supplied recycled bricks for an Ispwich QLD project which was featured in Australia’s Best Houses. The project won multiple awards for the House of the Year in the 2014 Queensland Regional Architecture Awards and the Gold Award for Excellence in Design in the 2013 Ipswich City Council Awards [5].

Recycled Plastic Insulation

Recycled Plastic Insulation is a construction insulation product manufactured from recycled plastics. The product is relatively new to the construction market with only a few handy suppliers worldwide.

A main supplier of recycled plastic insulations in Australia is AUTEX. The company supplies recycled plastic thermal insulation under the product name ‘GreenStuf Home Insulation’. Their Thermal Batts can be used for thermal insulation of ceilings, internal and external walls, and mid-floor cavities.

Greenstuf is manufactured from 45% recycled PET plastics. Polyethylene Terephthalate or PET as known, are plastics such as clear water and soda bottle containers. “As a material, PET is globally recognized as a safe, nontoxic, strong, lightweight, flexible material that is 100% recyclable” [6].

-Naati Akauola 

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If you are looking to build and you want the job done right with the quality your project deserves please contact Carmel Homes. 


1129 Toorak Road

1300 79 28 29

[1] James Aldred & John Day

[2] Wagner -

[3] GCI, The University of Queensland -

[4] Wagner -

[5] Australia’s best houses,

[6] What is PET,, 19/04/17

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