Plastics in the Construction
- As technology has developed, the use of plastics in construction has increased dramatically over the last 50+ years
- There are several different types of plastic used in building. Some are more envrionmentally damaging than others. All use oil resources.
- Around 1m tonnes of plastic is used by the sector every year.
- The industry is the second highest user of plastics after packaging (source: BPF)
- 25% of construction industry plastic is used in packaging- 3/4 of which goes to landfill
- CO2 emissions associated with construction industry plastics is around 3 Mt or 2% of all emissions from the construction product sector. (source: BIS, 2010)
- Overall, plastics are responsible for 10% of all oil consumption
- Environmentally, plastics can be a mixed blessing. When used appropriately, plastic can reduce the overall environmental impact - but otherwise its use can be unnecessary and damaging.
How plastics are used in construction
Insulation
Insulation to minimise heat loss from the house is found in the walls, roof and ground floor.
Walls:
Boards made out of Phenolic foam, Polyurethane (PUR), Expanded Polystyrene (EPS) or Extruded Polystyrene (XPS). Plastic based insulation boards are used because of their high efficiency to thickness ratio - leading to less space taken up within the thickness of the walls compared with fibre-based insulation materials such as glass wool or rock wool.
Roof:
Insulation boards are used in much the same way as in walls - sandwiched between, above or below the roof rafters. Again, plastic-based insulation represents and thinner section for the same amount of insulation value as the fibre-based alternatives.
Ground Floor:
Heat is lost downwards through the ground floor. Where a concrete slab floor is used, insulation must be load-bearing under the weight imposed on the floor as well as from the concrete. Although other materials are used, the most common ‘load-bearing’ insulation boards are made from Expanded Polystyrene (EPS), Polyisocyanurate Foam (PIR) or Extruded Polystyrene (XPS).
Environmental Impacts
All the above plastic insulation materials are derived from oil or natural gas - both diminishing resources. Much fuel energy is used in their production and air pollution is a necessary bi-product according to environmental pressure groups. The counter argument is that because these materials are highly efficient in producing insulation against heat loss, then they represent a proper use of oil where space efficiency is needed in a design.
One material though is widely considered as an environmental pollutant. Expanded Polystyrene (EPS) is a very common insulation material in floors, but most well-known as a packaging material. Nearly everyone will be familiar with the lightweight packaging accompanying things like computers and televisions as well as trays, cartons and disposable cups. It is theoretically recyclable, but in the UK the actual amount recycled approaches zero. Instead it is sent to landfill where, because of its bulk, it occupies a lot of space. We will be equally familiar with the way exapanded polystyrene breaks down into small pieces and individual beads - we now know through alarming reports from ocean research that polystyrene beads are readily found in the food chain. In view of this, many people aware of it’s pollution potential, would avoid using it where they can.
Alternatives
There are many options available to plastics insulation. Though none of the alternatives are as effective in terms of thickness, the environmental impacts are much less.
Alternative insulation materials will include mineral wool, wood fibre, sheeps wool, cellulose, hemp and cellular glass.
Windows and doors
Unless built in areas such as old towns subject to planning restrictions, nearly all houses built by developers include uPVC (un-plasticised Polyvinyl Chloride) windows and doors. So pervasive has the invasion of cheap plastic windows become, that a once varied urban landscape of painted coloured windows has been replaced by universal white plastic.
Environmental Impacts
PVC is made from a combination of Chlorine (from sea salt) and Ethylene (from oil or gas).
According to Greenpeace PVC is ‘… one of the most toxic substances saturating our planet and its inhabitants. PVC contaminates humans and the environment throughout its lifecycle: during its production, use, and disposal. Few consumers realise that PVC is the single most environmentally damaging of all plastics. Since safer alternatives are available for virtually all uses of PVC, it is possible to protect human health and the environment by replacing and eventually phasing out this poison plastic.’
Only about 25% of PVC is recycled. The remainder is either incinerated or goes to landfill. (source: WRAP, 2016)
Alternatives
Traditionally, the windows and doors to our homes were made from timber. Timber and combinations of timber and aluminium (‘composites’) offer up high performance and low environmental impact products.
Above and below-ground water and waste pipes
PVC and HDPE are used extensively for above and below ground drainage:
- Rainwater gutter and downpipes
- Waste water pipes from WCs, sinks, baths and washing machines.
- Below ground waste / sewage pipes.
- Water supply piping
Environmental Impacts
The impact of PVC is that described above for 'Windows and doors'; HDPE is far more benign but is also an oil-based plastic
Alternatives
Rainwater gutters and downpipes (aka ' rainwater goods'):
Use Aluminium, Cast Iron, Copper or Galvanised Steel products. They will be slightly more expensive, but more durable and easily recyclable.
If you need to use plastic, use High-density Polyethylene (HDPE)
Waste water pipes from WCs, sinks, baths and washing machines:
It's difficult to find a substitute for these pipes, but HDPE will be preferable to PVC
Below ground drainage:
Vitrified Clay or Ductile Iron pipes.
Water supply pipes:
These are set by your water supplier. The standard material (coloured blue) is Polyethylene (PE). There is no current non-plastic substitute.
Electrical Cables/Wiring:
PVC because of its electrical insulating properties has become a popular choice for electrical cables and wiring. So pervasive has PVC coating and shielding become, that alternatives have found it difficult to contest the market. However, they do exist.
The main alternative power cables, in the high and medium voltage range, use polyethylene as an insulation and sheathing material. Rubber sheathed cables are also available. For low voltage uses such as domestic wiring, the alternatives are polyethylene or rubber insulated halogen free cables.
Sheet and tile floor coverings
Floor coverings in kitchens and other high traffic areas has become one of PVC’s great success stories. It’s flexibility and durability combined with the potential of rendering an near infinite number of decorative options - including mimicking other natural materials have made it immensely popular with consumers.
Environmental impact
As per PVC materials above. In addition to which, because of vinyl flooring's close contact with humans, other issues have arisen, notably the use of oily liquids called plasticisers. Though the use of carcinogenic phthalates are being replaced as plasticisers, there is still a fear of the unknown qualities of their replacements. Furthermore, potentially hazardous Volatile Organic Compounds (VOCs) are emitted, particularly immediately after installation.
- Vinyl flooring decomposes and releases toxic gasses, mostly hydrogen chloride, long before bursting into flames. (NYS Office of the Attorney General)
- A study published in 2013 found vinyl flooring linked to asthma in children. (International Journal of Indoor Environment and Health.)
- Vinyl floors can be recycled, but currently almost never are.
Alternatives
Linoleum is made of renewable materials and consists mainly of vegetable linseed oil where a natural resin is added. Modern Lino has developed a wide range of decorative treatments to rival vinyl.
Cork, wood or ceramic tiles.
