A circular economy makes better use and re-use of materials, but what practical steps can be taken in the built environment? 

Dr Jeremy Gibberd, a professional architect with specialist expertise in sustainable built environments, discusses circular opportunities for built environments. His focus areas are methodologies for integrating sustainability into built environments and designing circular economy strategies for developing country contexts. 

Circular economy 

According to Dr Gibberd, there are three principles for designing a circular economy: 

• Eliminate waste and pollution by design. 
• Circulate products and materials at their highest value. 
• Regenerate nature. 

Circular products 

What are circular products? These are products that are usually made, maintained and repaired locally. They follow the principles outlined above and may be biobased and have recycled content (developed from grown materials and include materials that may have otherwise been directed to land fill).  

Mycelium building blocks. Image credit: MycoHab, Namibia

They aim to achieve high performance and have a long life. This is supported by being easily upgraded, maintained and repaired. With a local focus, circular products reduce reliance on imports and support the creation of local small enterprises and jobs.

Some examples are shared below: 

• Reused building materials and components from deconstructed buildings. 

  • Materials retrieved from buildings during refurbishment and demolition. These are sorted, repaired and made available for further use. 
  • Common materials include roof sheeting, sanitaryware, doors, windows, bricks, block, furniture and fittings. 

• Using agricultural waste for building materials. 

  • Agricultural waste from maize, sorghum, wheat and rice can be processed and used as building products. 
  • For example Strawtec uses compressed wheat and rice, wrapped in recycled paper, to form building panels. Panels can be used for external walls and internal partitions. 

• Bio-based products 

  • Bio based products are made from grown products.  
  • An example are the Mycelium building blocks (MycoHab, Namibia).Chipped wood dust of the invasive plant, Senegalia mellifera (previously Acacia mellifera), are used for fuel pellets and growing mushrooms. 
  • Mycelium is the living body of fungi. It can be pressed into blocks and fired to make bricks for housing.

• Recycling waste products 

  • Waste streams such as paper can be used to produce building products.  
  • An examples is cellulose fibre loose-fill thermal insulation, made from wastepaper. 

• Indigenous materials and skills. 

  • Materials and products used in indigenous natural buildings are usually highly circular. Examples include the thatch and earth-construction based buildings found in many Southern African villages.  

Some advantages are shared below: 

• Reused building materials and components from deconstructed buildings.

  • Reduced energy, carbon emissions, costs and waste associated compared with new products.  
  • Small enterprises can be created to survey, extract, refurbish and trade materials and products.
  • However, barriers to implementation include: 
    • In some cases, such as steel, salvage costs are so low that reuse is not economically viable.  
    • Some may not wish to purchase ‘second hand’ materials which are perceived to be inferior. 

• Using agricultural waste for building materials. 

  • Reduce waste: 70% of agricultural by-products are wasted – not used/fed to animals. 
  • Very low energy, carbon emissions and waste associated with the product. 
  • Small enterprises can be created to manufacture and install products. 

• Bio-based products 

  •  Supports biodiversity 
  • Reduces waste. 
  • Can be used to produce food (mushrooms) as well as building products (block). 
  • Small enterprises can be created to manufacture and install products. 

• Recycling waste products 

  • Cellulose fibre loose-fill thermal insulation can be blown into spaces such as ceiling voids of existing and new buildings to improve thermal performance. 
  • Very low energy, carbon emissions and waste associated with the product. 
  • Small enterprises can be created to manufacture and install products. 

• Indigenous materials and skills. 

  • Locally sourced bio-based roofing and structure. 
  • Locally sourced earth-based walls and floors. 
  • Local skills. 
  • Easily maintained. 
  • Affordable. 
  • Passive environmental control. 
  • Adapted to local culture, living and working patterns. 

Key statistics 

• Approximately 75% of all materials extracted from the earth’s crust are manufactured into construction materials and products. 
• Buildings and the construction industry consume 36% of global energy, and produce 37% of energy-related CO2 emissions in 2020. 
• 10-15% of building material is wasted during construction. 
• The embodied energy of materials is estimated to account for between 15% and 60% of a building’s lifecycle energy consumption. 
• 24-40% of energy in existing buildings can be profitably conserved. 
• A minority of new buildings includes passive building standards at or near profitability. 
• 54% of demolition materials is landfilled versus some countries where only 6% is landfilled. 
• 50% of most city land is dedicated to infrastructure. 
• Congestion costs 2% of the gross domestic product (GDP) in many cities. 

Issue: Building more sustainably. 

Solution: Circular materials offer sustainable solutions as well as broader benefits for communities. 

For more information, contact Dr Jeremy Gibberd:  

Tel: 082 857 1318  

Email: jeremy@gauge.co.za  

Website: https://jeremygibberd.com/