Waste Plastic Composite Building Materials

The Institute of Applied Science and Technology has invested in an extrusion and injection line that produces roof shingles from virgin or recycled plastic resins and waste agricultural fibers.

Plastic composite materials are used in prefabricated, portable, and modular buildings. They can also be used for interior and exterior construction projects such as:

  • Exterior cladding and wall panels
  • Roofs and Ceilings
  • Decks and floor tiles
  • Windows and Doors
  • Crown mouldings and baseboards
  • Bath and shower enclosures and sinks
IAST produces plastic composite materials by thoroughly mixing natural, pulverized agricultural fibers with a thermoplastic resin (waste water bottles, HDPE, etc.) and additives (dyes, chemicals for UV and fire protection).

The mixture is extruded with a parallel twin screw extruder to form a homogenous melt strand that is converted to pellets.

The pelletized material is heated until it is sufficiently fluid to allow for pressure injection into the shingle mold where it solidifies quickly.

Sample Tiles:
 
Advantages of Roof Shingles
  • Less costly and a lower maintenance alternative to more expensive roofing styles e.g. asphalt, clay etc.
  • Lighter than conventional clay or concrete tiles and can be installed over standard roof structures
  • Can be made from recycled materials like plastic bottles and natrual waste fibers (sawdust, bagasse).
  • Projected to provide a long-lifetime roof (based on material property assumptions).
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The shingles assembled on a pilot project roof

IAST estimates a cost of G$280 to manufacture a 16″ (40cm) x 10″ (25cm) plastic composite roofing shingle.
 
Since 2014, significant effort has expended to engage the private sector in securing an investor to take this project to a commercial scale.