C O N T E X T 1 1 2 : N O V E M B E R 2 0 0 9 7 The first of the afternoon case studies was the regeneration of the Ebbw Vale Old Steel Works, incorporating a group of listed buildings on the land. PierreWassanaar of Stride Treglown Davies Architects presented this mixed-use scheme. The main theme was the fact that you could not put a price on the social and cultural value of a building. People just wanted to be a part of historic buildings. This was evidenced by the Gwent Record Office choosing to relocate to the completed scheme, largely because of the quality of the listed building. The second case study was Cardiff Castle, where conservation, economics, use of the site and access had been carefully balanced to achieve a successful heritage attraction. Advice from John Edwards, chair of the CIOB’s conservation group, was that the use of specially skilled people always pays off, in terms of longevity and, with new design, enhancing places and conserving value. Sioned Lewis of Arad Consulting had led on the Valleys Built Heritage Project, highlighting the economic benefits of a conservation-based approach to traditional buildings and streetscapes in theWelsh valleys. The study was commissioned by the Heritage Lottery Fund, Cadw and conservation professionals. Lewis concluded that economic benefit could accrue from an investment in heritage, as an amalgamation of a number of small benefits. The story of the restoration of Great Milton Hall was presented by Richard Spencer Dean of Page and Dean Consulting. This Grade II listed historic house was in a dangerous state of repair and the interior had been lost. The aim of the restoration was to provide an energy-efficient building. The key was calculating the embodied energy, to offset any differences between the heat loss of the restored building against the building regulations requirements for acceptable heat loss. Using the embodied energy calculation for conversion, the energy of Great Milton Hall could buy 1.1m kWh of electricity. ‘The value of embodied energy saved can be seen or expressed to offset extra heating costs for over 50 years,’ Dean said. Professor TomWoolley of the Centre for Alternative Technology argued that sustainability was about getting priorities right. He pointed to too much emphasis on micro-renewables and gadgets, and not enough on the building fabric and the benefits of leaving building fabric in place. New build generated carbon dioxide and squandered resources. Each cubic metre of concrete used created at least 0.37 tonnes of carbon dioxide emissions. Around 10 billion tonnes of concrete was used globally each year. So re-using existing building fabric was more sustainable by reducing the consumption of new materials. The green claims of signature and iconic buildings proved to be ‘greenwash’,Woolley claimed. Many in the industry were interested in ticking boxes rather than understanding environmental principles.We were currently handicapped by inadequate standards and science, a lack of good data and poor methodologies to define sustainable building. Carbon neutral claims were based not on the neutrality of the materials themselves but on carbon offsetting. Specifiers often choose to ignore the impact of the production of materials and building products. Most modern building methods relied on foams and chemicals, glues and sealants. These were bad for the environment and our health, and might not be sustainable. Woolley believed that fundamental mistakes were made when such toxic and synthetic materials were used in building renovation. It might be years before the problems became evident. Polymer renders and styrene insulations were already the subject of court cases in the USA. Buildings using synthetic materials had an increasingly damaging effect on health. Brominated fire retardants (polybrominated diphenyl ethers) and other toxic chemicals used in building had serious health and environmental impacts. Studies showed there were high levels of these contaminants in our blood. These chemicals had spread throughout the planet, and were even affecting the health and the hormones of people in the Arctic. By contrast, natural materials such as hemp were able to absorb a great deal of water and release it again without damage. It could control internal humidity, and bonded with existing masonry and other natural materials. It provided good insulation and had thermal mass, so it stored warmth. It was breathable, so it was moisture permeable. It insulated without isolating existing thermal mass. Due to the effect of lime, it was durable and resistant to rot, mould and insect attack. Natural materials provided a viable alternative way to build. They could be robust, economical, locally sourced, breathable, good insulators and could even lock up carbon in the building. They provided a real solution to sustainable building problems. Natural materials were better for the environment, whether they were nonrenewable like earth, or renewable like timber, hemp and wool. They could be good for the economy by creating local jobs, boosting agriculture and reducing road miles. Natural materials could perform better in buildings, buffering moisture, bonding better with existing building fabric and reducing levels of toxic chemicals, improving indoor air quality. Debbie Maltby, conservation and built environment officer with Derby City Council Cardiff Castle (Photo: Fiona Newton)
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