Environmental impact of timber hoarding and how to reduce it
On average building a house can produce 1000kg of waste wood(1). A large proportion of this waste is contributed by single use timber hoarding. But construction companies are obliged to secure sites from unauthorized access by the Health and Safety at Work Act 1974. No work is permitted to take place until a secure barrier is in place around the site. The act states the qualities of that barrier, but not the material. The question is what is the environmental impact of using timber hoarding and does using plastic hoarding stack up as an alternative from an environmental impact view point?
What is the source of the environmental impact of timber hoarding?
The traditional timber hoarding is made with particle board or plywood. Particle board is made of pressurized woodchip and glue. Ply is made of sheets of wood glued together under heat and pressure. Upon installation, hoarding is painted and nailed or screwed to solid wood posts around the site boundary to secure site access.
The exposure of timber boards and supporting framework to weather, over time causes buckling that leaves the edges of boards exposed. This in turn presents a easy entry point for water to penetrate the structure of the board. Eventually such exposure is what causes the delamination characteristic of timber hoarding. In the British weather, one can see substantial degradation in timber hoarding in under a year for these reasons. For sites with longer on-going construction, it may be necessary to replace boards part way through construction to preserve the security of the site. And that takes us to what happen to timber boards at the end of use.
What is the scale of the environmental impact of timber hoarding?
Due to weathering and other damage (e.g. fixing screws and nails) timber panels cannot be systematically be reused. Unfortunately timber hoarding panel board is largely not recycled due to its mixed composition (glue, metals, paint and wood). Also use of timber hoarding in biomass is also not possible due to the mix of materials presenting a risk of creating noxious fumes upon incineration. So at end of use at a particular site, particle board and ply hoarding is mostly sent to landfill.
When a new site is established, the cycle is restarted with its negative environmental impact. With timber panels largely imported to the UK, with the carbon emissions associated with that transport. Once installed, the boards deteriorate until they are eventually sent to landfill. And this isn’t a minor issue. DEFRA(2) and Bovis(3) give total particle board waste generated annually from UK construction sites in the region of 100,000 tonnes(4).
Environmental impact reduced with Perimeters hoarding
But how could this impact be reduced? To start with Perimeters sources its reusable puPVC hoarding exclusively from UK manufacturers. This reduces transport emissions not only as Perimeters boards have a shorter journey than imported timber(6). But because Perimeters boards are used and reused multiple times, that advantage in reduced transport emissions is multiplied. And not just for the end product, the materials needed to make the timber boards are also transported to their factory. By using Perimeters’ reusable hoarding all these transport emissions are avoided. In addition Perimeters hoarding is 30% lighter per linear meter than timber hoarding, further reducing transport emissions.
But the biggest improvement in environmental impact is reducing the material sent to landfill. Here using Perimeters reusable hoarding would represent at least an 80% reduction over a typical board’s lifespan(5).
(2) Wood waste: A short review of recent research. Refer to figure 2: Composition of construction wood waste (DEFRA, 2011)
(3) EcoBoard RePlaS: Reducing the amount of plastic sent to landfill, to reduce the carbon footprint of temporary works (2007)
(4) Given the lack of reuse, annual waste will approximate to annual consumption
(5) EcoBoard RePlaS: Reducing the amount of plastic sent to landfill, to reduce the carbon footprint of temporary works (2007) cites a study by Environmental Recycling Technologies plc showing that per life cycle kg CO2 efficiency of hoarding made with 100% recycled materials is approximately 500% greater than particle or ply hoarding (8kg vs 40kg/38kg respectively).
(6) www.globalwoodmarketsinfo.com 25/1/2016 “Timber and woodbased panel imports boom in UK ”. Also UK Timber Trade Federation (TTF) Statistical Review 2015 notes 60% of panel is imported