Simon Corbey from ASBP shares some of his research into the costs and life cycle of plastic windows and suggests some considerations for self-builders.
Interview with Simon Corbey
Simon Corbey worked as a chartered surveyor in the ‘90s, and went on to become a specialist in natural paints for London's first eco builders' merchant, Construction Resources. He has also worked for BioRegional, the Sustainable Development Foundation, the Good Homes Alliance and the Alliance for Sustainable Building Products (ASBP). Last time we spoke to Simon, he talked to us about healthy building products.
We should question the chemicals in uPVC
Simon Corbey has been working on behalf of the ASBP to compare plastic and timber windows. Consumers tend to be more concerned with how windows will look and last than where plastic comes from and the issues around it. Simon remarks that plastic windows are manufactured widely in the UK, but these impacts are not really considered, adding, “I do think that there's an opportunity for the UK to develop their building physics and approaches to making windows.”
Simon notes that plastic windows appeal, as they are generally cheaper and available in a range of styles. He describes the marketing as aggressive, adding, “It’s well funded, of course. It’s the petrochemical industry.” Plastic windows contain a range of chemicals but no research has suggested a negative effect on indoor air quality. The window itself may be benign, but Simon has also been researching product manufacture and life cycle.
Manufacturing chlorine is hugely energy intensive
Simon explains that uPVC (unplasticized polyvinyl chloride) contains chlorine. Used in swimming pools and our water supply, it’s common enough to not raise concern. However, he explains that its manufacture has an incredible impact on the environment.
Simon estimates that producing 80% of the UK’s chlorine uses more electricity than Liverpool. Production of PVC in Europe in 2015 used 8.6 million tonnes of chlorine. “So it’s hugely energy intensive,” says Simon, adding, “From a life cycle analysis it’s a terrible, terrible thing.”
Simon’s research shows the hidden costs of uPVC windows
Simon has further researched Ineos, who produce most of the UK’s chlorine. Describing it as “a very murky world,” he says he feels motivated to bring this to people’s attention. The site of the Ineos plant in Cheshire is of particular concern. Simon describes how Ineos were caught dumping mercury into the Manchester Ship Canal in 2014 and the land contains a dump once used to “make everything from nuclear weapons to World War II stuff”.
Previously owned by ICI, the dump was linked to toxic chemical leaching and reports of ill health in the early 2000s. Today, explains Simon, if you look at the Land Registry, this dump apparently has no owner. “There is a completely toxic dump just there which the council don’t own,” he says. “Ineos have somehow redrawn the lines of their site and conveniently they don’t own it any longer.”
Timber windows struggle to compete on price and marketing
Despite their significant environmental price, plastic windows remain cost effective for manufacturers. The price of oil and gas is still low, making the raw materials cheap. The process of gathering timber, processing, sawing and milling it is quite energy intensive in comparison and the end product is heavier to transport. All of this adds to cost.
Simon further points out that the UK timber industry is quite fragmented, containing many different disparate interests. Conversely the plastics industry markets products with “one voice”, typified by slick campaigns, such as that for Everest windows. Moreover, Simon describes it as quite litigious, recalling a threat of court action when his former employer persuaded a Scottish Housing Association to cancel their order for plastic windows.
Plastic windows may not outlast timber
There is a perception that timber windows will rot, requiring repeated maintenance, while plastic is assumed to be tougher. Simon questions these preconceptions. While acknowledging that timber windows have a finite life cycle he points out that plastic windows are prone to yellowing after a while. Simon himself has 120-year-old timber windows, which are “going strong”. “They’re a bit leaky,” he says, “but they’re okay as far as I’m concerned.”
Other options for window materials do exist. Simon recommends considering factors such as product life cycle and building location. Aluminium is very durable but highly energy intensive; composite timber and aluminium windows are one alternative.
The quality of UK timber windows is improving
Windows are an essential part of the building fabric’s performance. With improvements in building science, double glazed and triple glazed windows are appropriate for new builds and both plastic and timber windows can achieve Passivhaus Trust certification.
Where good indoor air quality is maintained by natural ventilation, windows must function well, being easy to open and clean. There have been some issues of quality with some timber windows but Simon sees this improving, following the standard of European and Scandinavian manufacturers.
Recycling plastic windows involves additional expense, chemicals and risks
The Scottish Civic Trust suggests that the recycling rate for windows might be 3% and according to the Green Guide, BRE suggest that the UK average is about 15%. However, Simon suggests the many issues with recycling, such as the chemicals and risks involved, make that figure optimistic.
The formulation of plastic has changed quite a lot since the ‘60s and the industry has made great attempts to clean itself up. Substances considered by REACH to be of very high concern, such as lead and cadmium, are being phased out although tiny quantities are still allowed.
Plastic is worse than wooden windows in a fire
Simon believes that toxicity is a huge issue. He confirms that plastic windows pose a greater risk than wooden ones in the event of a fire and believes that more research is needed. However, currently all the testing institutes are very busy “as a result of Grenfell”.
Simon notes that in the USA, The Healthy Building Network has liaised with the Fire & Safety community to argue for a complete halt to use of plastic products. Likewise, the ASBP has initiated contact with Kent Fire and Rescue and the London Fire Brigade. As Simon explains, “there is some research underway but it’s early doors, I would suggest, this type of testing.”
Industry and consumers are moving away from plastic
Techniques and attitudes continue to change. Acetylated wood is an example where window science has improved. This process basically uses vinegar to extend the maintenance life of timber to over 60 years.
Simon notes a growing interest in health and wellbeing, as well as a global campaign against plastics. He summarises, “I think at ASBP we’re trying to suggest that as a society we’ve just got to start using less plastic through and through, in all the things that we do and windows being one of those things.”
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