Specifying truly sustainable materials that tick every box is a specialism in itself – but Katie Puckett has canvassed the experts to find out what should be on the list.
When it comes to sustainable building, the march of progress is less a straight line than a meandering path with many forks, frequent hairpins and quite a few dead ends.
The result is that 2015’s product landscape is an unlikely combination of the very new and the very old. High-tech solutions such as LED lighting and 3D scanning will reduce the energy use of buildings, whereas low-tech materials such as clay and wood will enjoy a renaissance as people search for renewable materials with low embodied carbon.
Considering how far the construction industry stills needs to go – the government’s Construction 2025 strategy is seeking a 50% cut in emissions – it can’t afford to leave any stone unturned. “We need innovation across the board,” says Kristian Steele, senior materials consultant at Arup. “Every material used in a building needs to be developed to reduce its impact, and I think we need change across all of the supply categories.”
As for what makes a sustainable product, Steele identifies two categories: “First, it’s got to do the job it was specified to do, whether in a column, a wall, a lighting system or as a flooring material. If you get that wrong, it will burn, crack, fade, fail and you will need to replace it before its time is out.” This is familiar territory for specifiers and it’s the side of sustainability that the industry generally does well.
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The second aspect – and it remains a distant second – is the effect a product has on people and the environment over its lifetime. Manufacturers have already begun to decarbonise their supply chains, and to compile environmental product declarations (EPDs), a harmonised EU standard for life-cycle assessments. “But there’s a long way to go before we have all of the information we need about all of the impacts of all of these products,” says Steele. “In Europe as a whole, there are millions of products on the market, but only about 2,000 EPDs so far.”
Sustainable building technologies may have come a long way in a short space of time, but even the latest innovations are just small steps towards the goal of a radically different industry. For example, today’s zero carbon new builds and green retrofits are not end products in themselves, but stages towards the much more ambitious goal of buildings as components of integrated energy networks – a point made by Professor Chris Gorse, who leads the building performance and sustainability research unit at Leeds Beckett University. “Before we can get there, we’ve got to have greater control of the building stock. We need to know how buildings behave and how to control them, how quickly they heat up and down, how much heat energy they can store and how much energy they can generate. The building fabric is critical – buildings can’t be draughty or simply react to the external environment.”
Another ambitious goal is a shift towards a “circular economy”, in which everything is reused or recycled. For construction, the transformation would take many decades, but there are already initiatives at a European, UK and industry level to develop more resource-efficient materials and processes.
There is also a growing “healthy buildings” movement. A World Green Building Council report was published last March, and the newly formed Building Biology Association UK brings a long-established German discipline here for the first time.
The BBA was set up by Devon-based architect Gale & Snowden. “We have strict criteria when selecting materials, based on building biology principles,” says director David Gale. “We’re looking for healthy materials that work dynamically with the building.” On the building biology scorecard, top marks go to timber and earth materials, while PVC comes bottom.
All of these focus on fabric performance over renewables introduced by the 2013 iteration of Part L – and are driving a back-to-basics approach for building materials and technologies, and perhaps a greater scepticism towards solutions that sound too good to be true. “Quite often new things are untested and don’t perform as well as they should,” says architect and sustainability consultant Bill Gething, citing the example of condensation and overheating in highly insulated buildings. “Most of the time, we don’t need a new product – rather, we need to use the products we already have better.”
Radical inventions may grab the headlines, but innovation is more usually a gradual process, agrees Jane Thornback, sustainability policy adviser at the Construction Products Association. “You do occasionally see a step-change, but that tends to be with the introduction of materials or processes that were developed outside construction, such as nanotechnology or BIM. But innovation is going on all the time among manufacturers, either through continuous improvement – the “men in sheds”
effect – or in response to a challenge. That’s what manufacturers love.”
Given the scale of the challenge ahead, that’s probably just as well…