Discarded soda bottles made from plastic could prove to be the ideal green roofing material.
Engineers have devised a new method for converting an item as common to global consumer culture as the plastic soda bottle into an outstanding green building material for the construction of roofs in impoverished rural areas.
David Saiia, professor of strategic management and sustainability at Duquesne University, has developed his plastic thatch with the raw material provided by discarded soda bottles, which can be readily sourced just about anywhere on the planet.
The method entails first lopping off the tops and bottoms of the bottles to leave just the cylindrical torso. The body of the bottle is flattened out and sliced into strips, which are then fastened to a cross-strip by means of an ultrasonic sealing device.
The resulting plastic thatch serves as a superlative roofing material which combines waterproofing with ventilation. The plastic is as adept at preventing the ingress of water and noise pollution as metallic roofing, yet its transparency and diffuse arrangement in the form of a thatch permits the entry of light and air.
The thatch could prove to be the ideal roofing material for rural areas in developing countries, where traditional methods for the construction of roofs suffer from serious drawbacks.
While traditional thatched roofs made from grass provide ample ventilation, they are susceptible to water-logging and can even collapse during violent storms.
Corrugated tin roofs, which have become a staple of rural housing and shanty towns in the industrial era, are capable of protecting occupants from rain and hail, but convert homes into ovens because of their propensity to trap heat in torrid weather.
In addition to providing comfort and protection from the elements, the thatched roofs developed by Saiia are cheap and easy to source from local waste materials, and are available in a variety of colours depending upon the bottle types used.
The plastic thatch also provides a further remarkable benefit - it serves as a Naturally Occurring Green Roof once it accumulates a sufficient amount of dust and debris.
Dust-sullied roofs would normally be deemed a negative, yet the plastic thatch enables orchids and other plants to take root in any accumulated debris, creating a natural green roof which serves to mitigate the impact of direct sunlight and extend the structure's longevity.
Saiia has founded the Reuse Everything Institute with partner Vannah Le to promote usage of the material, which they envisage as having broader applications for the construction of other structures such as fences and greenhouses.