C O N T E X T 1 3 3 : M A R C H 2 0 1 4 11 Recent significant long dry periods, or long wet periods, possibly associated with climate change, also cause problems. Although many foundation stratas may not be significantly affected, buildings on clay strata are vulnerable. Sections of buildings may articulate due to the drying out, shrinkage and swelling of the clay in these changing conditions, allowing walls to settle and move away from other more solid parts of the building that may not be affected, perhaps because of shielding from the weather. Experience over the last three years of significant cracking occurring to buildings on clay sites has caused the Morton Partnership to call in geotechnical engineers to establish the depth of desiccation (drying out) of the clay below the surface.This has undoubtedly caused, for example, chancels of churches to move away from the main body of the building.The geotechnical surveys have shown that, in the 14-month dry period a little over two years ago, clay was drying out to a depth of four metres, causing considerable settlement of the comparatively lightweight structures. In acting for the DACs in clay areas, and experiencing three church chancels moving away from the chancel arches, there is difficulty deciding on what action to take. This is because, although it would not be unreasonable to consider underpinning a structure to a depth of just below two metres, a depth of four metres would not be reasonable in terms of viability for the church. In one case the damage was so great that there was a suggestion MSc Conservation of Buildings Anglia Ruskin University, Chelmsford Are You… • A Property, Surveying, or Architecture Graduate? • A Non Cognate Graduate with Heritage Experience? • A Professionally Qualified Property Specialist? • Passionate about Heritage and developing your Career in Conservation? Our two year part-time course includes: • Conservation & Legislation (Philosophy and Implementation) • Facilities Management of Heritage Buildings • The Science & Economics of Historic Buildings • Surveying the Historic Building (Interpretation of Architectural Evolution) • Research Methods and Major Project (Dissertation) Start January or September Tel: 0845 271 3333 Email: FST-Answers@anglia.ac.uk Visit: www.anglia.ac.uk/conservation14 that the chancel arch should be blocked up because of the cracking.We have simply made good the cracks and the building remains stable. At the time of all this occurring, I offered to write a paper discussing the situation, but I decided not to recommend any action until we had assessed the situation historically over the centuries. I indicated that perhaps if we had a lot of rain fairly quickly, no further movement would occur. Amazingly it then rained after this long dry period for about six weeks.The result was that movement to these chancel structures stopped and we recommended that the cracks should be simply made good. It became apparent following research that such variation to the climate had not been unusual over past centuries. Most of our churches were built at least 700 years ago, and would have experienced many variations in dry and wet periods, surviving quite satisfactorily, so I recommend that it is reasonable to repair the cracks and leave it to the next generation to continue to look after the building by crack repairing. I have concentrated on the stone buildings because they demonstrate the philosophy that I have set out, but exactly the same philosophy can be adopted for domestic buildings of much lighter construction. In this case there are ways of flexibly strengthening cracks in brick walls by re-stitching across cracks to ensure continuity in the structure, assisting in laterally restraining this element of the building. Brian Morton MBE is a consultant to the Morton Partnership, a practice he formed in 1966. Join our world-leading Department of Archaeology and choose from an unrivalled range of courses: • Carry out cutting edge research at some of the most significant archaeological and historical sites in the UK, on your doorstep • Ranked in the top 10 of the University league tables, we are also recognised as a Centre for Excellence and were awarded the Queen’s Anniversary Prize in 2011 Conservation at the University of York Contact: Janine Lyon, Postgraduate Administrator Tel: +44 (0)1904 323963 Email: Janine.lyon@york.ac.uk Web: www.york.ac.uk/archaeology • York is the UK’s archaeological capital. It has probably the largest per capita population of archaeologists, conservators and heritage professionals anywhere in the world. • The University offers several bursaries for home students and a range of scholarships for overseas students. Conservation & Heritage
RkJQdWJsaXNoZXIy MjgyMjA=