12 C O N T E X T 9 1 : S E P T E M B E R 2 0 0 5 and local residents, and this can only be gained through discourse. David Armitage is chairman and managing director of the York Handmade Brick Company, which is one of the leading UK specialist suppliers of bespoke handmade and extruded products. His presentation took us back again to the practicalities of supply and sourcing. Armitage outlined the issues that underpin the brick industry – the availability of raw materials, sustainability, working within the minerals framework and environmental considerations – and how each of these is approached by his company. He discussed the production process and product, illustrating his talk with photographs of the products in use. Choosing, specifying and using brick for conservation work can be successful only if the texture, colour mix and size of the brick are carefully considered. But he was quick to point out that the bond pattern and mortar mix are also essential elements. This led neatly into the third session of the day, which concentrated on lime. Lime The opening presentation by Richard Smith, a recent MSc graduate of Oxford Brookes University and editor of The Building Limes Forum Journal, dealt with the basic principles of lime, what it is and how it is used. His presentation is printed on p17. Mike Farey, founder member of the hydraulic lime research team at the University of Bristol, and Daryl Birden, sales director of Singleton Birch, spoke on the topic of hydraulic lime, the history of its development as a product and the future. Farey spoke about the situation within the conservation industry regarding the historic positions of fat limes, fat limes with pozzolans such as brick dust, and hydraulic limes – and the distrust towards hydraulic lime shown by the profession over the years, some even equating it with Ordinary Portland Cement. In Farey’s view the situation was now very different, both as a result of practical experience using hydraulic limes over the past 10 years and following extensive research by English Heritage and the University of Bristol team. Farey summarised the current state of historical knowledge of hydraulic lime, and discussed the development of Singleton Birch and the threat posed to the homegrown industry by imports. Singleton Birch was founded in Manchester and moved to its present site at Chalk Hill in 1850. The company began making hydraulic lime in 1964 and has developed an expertise in its production. Daryl Birden was implicit in recognising that the success of the business and its future growth is dependent on the availability of raw materials, knowledge of the product and the market. The final presentation for the session was fromNigel Gervis and Jim Wrigley of Ty-Mawr. The company provides traditional lime-based building materials to most of the large building conservation companies in Wales and the borders, Cadw, the National Trust the larger jobs require even shapes and sizes, and once the stone is extracted the land is returned to nature. Jewett’s quarry has the laudable accolade of having the highest number of nightjars in the north of England, demonstrating that industry and conservation need not always be considered such odd bedfellows. The third talk of the day, by Graham Lott on petrography, is published on p16 of this issue. Brian Marker, based in the minerals policy branch of the ODPM, completed the presentations on stone sourcing and use. Marker explained the current planning system and its implications for conservation materials. Beginning with a brief outline of the policy framework, he spoke about the issues that often inform a decision for planning permission – for example, the requirement to safeguard resources for the future and to consider other land use issues. Economically the small-scale extraction that is often required for conservation purposes may not be viable, so large-scale extraction, with the material also used for new build, may be required to support the industry. Marker also explained that it is not as simple as re-opening historic quarries, as these have naturally regenerated and often become protected themselves as habitats for wildlife or for their geological importance. One message to come from the presentation was that there needs to be a clear understanding of the needs and wants of all interested parties, including the quarry company, English Heritage, English Nature JohnYates, IHBC chair, breaks for an informal lunch with fellow delegates at the ‘Material Matters’ Day School JohnYates (chair),Terry Hughes and Brian Marker at the session on stone slate roofing
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