There are some quick fixes to make your building sustainable, but they can have high carbon costs that aren’t immediately obvious. Time is the key
Should we design buildings for a 60 year or 200 year life? How good is our data, and how good does it need to be if we are to cut the whole life carbon of our buildings? These were some of the questions tackled in a round table discussion chaired by RIBA Journal’s Eleanor Young, with representatives from manufacturers, architects, materials suppliers, the construction team and the education sector. They were looking at building longevity, at how we should design buildings that will last longer, spreading the cost of embodied carbon over a longer (more realistic) period and – ideally – employing materials that can be re-used at the end of life. The talk ranged from the larger scale of buildings down to the details of materials.
While all the speakers agreed on the importance of longer-lived buildings, there were different approaches. Zoe Watson, sustainability specialist at Levitt Bernstein, said: ‘A big thing we have done is to change policy to design Passivhaus as default. Our designers are educated in passive design. Even if clients opt out later, it means that the actual design is energy efficient from outset.’
But others were doubtful. Simon Sturgis, of carbon consultancy Targeting Zero, asked, ‘Is Passivhaus the best thing? What about all those tapes, how long do they last? I have a sneaking suspicion that something slightly lower than Passivhaus may be the best whole-life carbon solution. If those tapes that are invariably buried in the fabric of building are impossible to get to, do they last 200 years?’
Louisa Bowles, partner and sustainability lead at Hawkins\Brown, saw ‘interesting tensions in embodied carbon measurements. There is a big focus on getting to 2030, and reducing carbon emissions now. But a lot of materials that enable us to massively reduce our embodied carbon emissions now don’t last that long or will need to be replaced several times over the length of the building’s life, increasing the embodied carbon emissions dramatically. Play with the data and some interesting things come out.’
Sarah Le Gresley, marketing director of brick-maker Michelmersh, which convened the discussion with the RIBA Journal, was particularly concerned about this. She felt that EPDs (environmental product declarations) often skewed the advantages of materials like clay brick, because they last so much longer. ‘You often hear the brick industry say that clay products last 200 years,’ she said. In fact, ‘We have brick buildings that have lasted 6000 years and clay brick has zero operational carbon, so taking a 60 year lifespan means you cannot accurately compare material whole life carbon cradle-to-grave for the realistic life span of our built environment We need a longer study period.’ Put simply, if you calculate the carbon cost of long-lived materials over too short a lifespan, you penalise the durable products that are less carbon intensive over the full lifespan of a building and beyond.
John Cave, executive director of materials supplier EH Smith, said, ‘We have continually been looking for products that can solve some of the issues. We have been involved with Passivhaus since it first came over. How do you make buildings more airtight, how do you improve ventilation, reduce thermal bridging? We are working with established manufacturers such as Michelmersh to see how industry can rise to meet the challenge.’
It is not just the materials that will give buildings a long lifespan. They must also continue to be liveable over a long period. Alex Lifschutz, director of Lifschutz Davidson Sandilands, has long been a proponent of ‘long-life loose-fit’ as a way of making durable buildings. He said he is concerned by standards that make new homes too small. ‘We always try to extend the scale, size and volume of apartments,’ he said. For instance, he believes that external balconies are rarely useful, especially above six or seven storeys. Instead they should be incorporated in the volume of the home.
Mike Leonard, chief executive of the West Midlands based Buildings Alliance, agreed. ‘The golden word is resilience,’ he said. ‘We are very much of the view that we must design for longevity, with buildings that are adaptable, flexible, not subject to over heating and resistant to fire.’
He warned: ‘We have to be very careful of unintended consequences. Governments and others are making decisions based on rhetoric rather than evidence. If we are shipping things halfway across the world and replacing them four or five times, is that really the solution to the challenges ahead of us?’
One answer is to ensure that we have valuable data, that we make decisions on the basis of knowledge rather than hunch. This can, however, be a minefield.
James Fiske, global director of data and information products at RICS, said: ‘We are trying to encourage the likes of QSs that when they measure for cost, they should measure for whole-life carbon at the same time.’ But, he warned: ‘Without data and consistent data we shan’t make the right choices. We need a way to share our experiences. The context behind that data is important as well – we need to tell what is and isn’t included.’
Sturgis worked with James Fiske on the RICS professional statement on whole-life carbon assessment, which is being updated, and also on the London plan. ‘I was very keen that we should ask for the most we could possibly get,’ he said. ‘If people didn’t quite understand, they would at least start to think about it.’ This meant including all the modules that define the life of a building, including Module D, which is the future life of elements after demolition. He said, ‘The opportunity for gaming that and cooking the figures is very high. But you need to start thinking about it.’
He also discussed the industry proposal to introduce a Part Z to the building regulations, which would cover whole-life carbon. ‘Part of the equation,’ he said, ‘is to get government to buy into this. As a special advisor to the Environmental Audit Committee, I am trying to convince them that whole-life carbon is sufficiently mature to be picked up and used by government. It’s a developed methodology. I have been speaking to a number of government departments who realise that they need to know more.’
Governments and others are making decisions based on rhetoric rather than evidence
Le Gresley said, ‘One of our biggest problems is the transparency, quality and accuracy of that data.’ The latest clay brick EPD includes Module D [cradle to grave] and is collated from a wide variety of manufacturers data, but she is concerned that manufacturers of other materials do not follow the same transparency. Therefore the data is not comparable for architects and specifiers. And it is vital, she argued, that data can be updated rapidly as companies like hers make significant steps to decarbonise processes.
Dr Solomon Adjei, senior lecturer in quantity surveying and construction management at Birmingham City University, said: ‘Regulation is great, but to what extent does it cover everybody down the supply chain? How does it translate to the people on site? For example, RICS Module C [design for deconstruction] is never in the thinking of people on site. How do we ensure that we cover everybody within that?’
The discussion also covered the massive question of retrofitting existing buildings. As Alex Lifschutz said: ‘Refurbishment is where the battleground is. We have 25 million dwellings. How do we upgrade and make sure they last another 200 years?’
This was a wide-ranging discussion, which showed both how much interest, concern and knowledge there is – and how much further we need to go. Fast. It is not just students who need to step back and think about how long their buildings and materials will last, architects and the whole construction industry need to think longer. The last statement should come from Simon Sturgis. When asked what was the most important move for the future, he said: ‘Education, education, education.’
Long term benefits
Brick is non-toxic and made from natural raw materials which are locally sourced. It requires little to no maintenance, is non-combustible and improves indoor air quality – and it contributes to the building’s thermal mass performance and acoustic insulation values. It can also be recycled and re-used at the end of the building’s life, going on to benefit multiple generations.