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Recycled polystyrene housing foundations to protect from seismic damage

Recycled polystyrene housing foundations to protect from seismic damage

A new Wellington housing development will use an innovative foundation design employing polysterene waste to ensure the houses can withstand seismic activity much better than homes built on traditional concrete slabs.

Poly Palace, a polystyrene recycler based at the Spicer Landfill in Porirua, has completed a contract that sees a large volume of the Wellington region’s polystyrene waste compressed and used to provide a better foundation for new council homes.

The plan is this: Before the concrete is poured for the foundation of these homes, Poly Palace’s 100 percent recycled polystyrene ‘pods’ are laid in a grid. The concrete is poured to form the floor then moulds around the polystyrene and reinforcing steel to form a ribbed raft waffle slab that is significantly stronger, and provides better insulation, than a traditional concrete floor slab.

Poly Palace’s owner and manager, Richard Moore, says the pod ribbed raft is unique because the solid polystyrene pods are entirely recycled from polystyrene waste, including consumer packaging and super market trays.

“We’re providing a stronger, safer and insulated foundation for a significant council housing project,” says Mr Moore. “But we’re also removing a large volume of polystyrene waste from landfills.

“If we took each house and filled its ground floor with polystyrene waste 1.2m deep, this is an indication of the volume of post consumer waste that is required to form the solid polystyrene ‘pods’.”

The use of Poly Palace’s solid pod system in the Regent Park development was investigated and compared to other ribbed raft systems, before being recommended to Wellington City Council. The development was designed by Designgroup’s Stapleton Elliott, project-managed by Spencer Homes and constructed by Hawkins Construction.

Poly Palace recycles waste polystyrene at its recycling plant at Spicer Landfill into two separate product lines:

• Clean building grade, flame retardant polystyrene is recycled into 50 percent recycled sheets and profiles, including an underfloor plank for new or retrofit wooden floors.
• All other polystyrene wastes are processed separately into 100 percent recycled products such as ‘Palace Pods’ for void forming in concrete floors, and Palace Porous for drainage applications.

The foundation ‘pods’ are produced in a moulding process in a factory on the Spicer Landfill site, which is jointly managed by the Porirua and Wellington city councils.

Porirua City Council’s Zero Waste Co-ordinator Tushara Kodikara, responsible for managing the council relationship with Poly Palace, says “'this is a great initiative, where polystyrene waste is up-cycled into products that provide real gains in terms of the long term sustainability of council housing stock.

“In a guaranteed long-life out of landfill these recycled pods achieve real gains in durability, insulation performance and CO2 mitigation. Poly Palace is an excellent example of Porirua City Council working with other councils in the region to lengthen the life of Spicer Landfill and assist businesses and the community to find alternatives to waste."

Poly Palace was a finalist in the Wellington Regional Gold Awards Inaugural Green Category in 2007, and won the Porirua Business’s Environmental Award that year for recycling waste polystyrene into home insulation.

“The polystyrene we take is typically short life, and destined for landfill, either from construction off-cuts or packaging from consumer appliances,” says Moore. “...We use it to make products that under the New Zealand Building code we guarantee as having a useful life of at least 50 years minimum.”

If a significant earthquake was to hit Wellington, the expectation is that increased use of the pods system will assist houses, such as those in this council development, get a green sticker and remain habitable.

The polystyrene packaging waste foundations can expect a future that extends generations beyond the life of the appliances that the polystyrene was originally created to protect, says the council.