The Desert Rose’s second skin wall was designed and built by Team UOW students. The concrete wall is our second skin wall, it acts as a shading element to the regular cladding of the walls and absorbs the solar heat rather than the walls of the house. The wall has a series of holes in it and is open to the air both top and bottom to allow air to freely move around the wall and cool the concrete at night.

The second skin wall is made out of an innovative lightweight foamed concrete that uses recycled glass powder as a cement replacement – a mixture developed at UOW. Across the Desert Rose’s second skin wall 705kg of recycled industrial glass powder was used which is the same amount of glass as 3710 glass Coke bottles. Using the recycled glass mean there was a saving of 350kg of cement with no reduction in concrete strength. This proved to be an excellent use of a material that would have otherwise ended up as waste entering landfill.

To account for the loss of strength in the concrete due to this lightweight mixture the wall utilises Denso Australia’s carbon fibre grid reinforcement material. The grid reinforcement is an innovative engineering material that provides a means of stress transfer during concrete shrinkage, greatly enhances the ductility of the thin concrete elements and it extremely lightweight making it especially suitable for the Desert Rose’s main architectural feature. This carbon fibre grid is corrosion resistant which is crucial to allow the second skin wall to be only 50mm thick and avoid concrete damage from corrosion of reinforcement.

Approximately 292kg of CO₂ was saved through using recycled glass as a cement replacement in our second skin wall, this is a 10% CO₂ reduction when compared to a similar foamed concrete mix without glass. In addition to this, the decision to use the carbon fibre grid as reinforcement meant we were able to reduce the thickness of the wall by 33%. Combining these together resulted in a 40% reduction in cement required versus a conventional foamed concrete wall.