Journal of Architectural Conservation
Volume 4 Number 3 November 1998
The Treatment of Timber Decay into the 21st Century Brian Ridout
Letting the Building Speak An Interview with Sir Bernard Feilden Derek Linstrum
Cathedral Care and the Influence of Funding Michael O'Connor
Algal and Lichen Growth following Chemical Stone Cleaning Maureen E. Young
Urban Conservation Policy Development: Character Appraisal and
Much of the work that is currently being undertaken on historic buildings and monuments attempts either to follow craft precedents or else to reinstate or restore original fabric using modern materials and methods of construction. At the same time, techniques of repair and maintenance continue to rely on principles and practices that have remained unchanged and often unchallenged for generations.
As architectural conservation, in all its guises, develops and grows as a recognized profession, it is important for all of us to reassess some of the approaches that have been taken in the past and to ask questions such as why, when and how our actions should be proposed, planned and implemented today and in the future.
In Algal and Lichen Growth Following Chemical Stone Cleaning, Dr Maureen Young of the Masonry Conservation Research Group, Robert Gordon University, presents the results of recent research undertaken to assess the relationship between chemical cleaning and the appearance of biological growths on certain Scottish sandstones. The results of this work indicate the need for caution when using particular chemical cleaning methods on porous stone types, and provide practical guidance to practitioners involved with such matters.
Repairing and maintaining large and often complex buildings of international significance make demands on all those who are responsible for planning and implementing such works. Dr Michael O'Connor, Deputy Clerk of Works and Foreman Mason at Lincoln Cathedral, has had many years' experience of such responsibilities and draws on them to outline some of the difficulties faced in carrying out works under current funding arrangements. Cathedral Care and the Influence of Funding makes an important statement that should be heeded by all those who have authority in such projects.
Research into the effects and subsequent treatment of beetles and fungi that affect our buildings and monuments has been going on for much of the twentieth century. In recent years, however, attention has been given to reassessing this work in the light of changing expectations and construction or conservation practices. Dr Brian Ridout, a well-known practitioner in this particular field, presents in The Treatment of Timber Decay into the 21st Century a summary of his work and offers a personal view on how attitudes are changing with regard to the specific treatment of historic fabric.
For those who work in town planning and urban design, Dr Andrea Mageean's paper entitled Urban Conservation Policy Development: Character Appraisal and Analysis should be of particular interest. In this, consideration is given to both conceptual and practical issues relating to reconciling conservation with pressures for change. The case for undertaking morphological analyses of conservation areas as part of the management of conservation and design processes is well argued and presented.
The occasional interviews published in the Journal are a means by which the views and opinions of those who influence, through word or action, the practice of architectural conservation can be shared with the readers. In this issue, Professor Derek Linstrum, himself such an influential person, presents an interview with the Patron of the Journal, Sir Bernard Feilden. Entitled Letting the Building Speak, it presents some of the achievements of this remarkable man, and at the same time provides a glimpse of the astute and quick-witted personality that has been an inspiration to so many students and practitioners from around the world.
The Treatment of Timber Decay
into the 21st Century
The treatment of timber decay during the past 50 years has frequently been destructive and usually required large volumes of biocides. This phenomenon belongs to the twentieth century. Now that public opinion is veering away from the use of biocides in buildings, there is a desire to return to philosophies developed 200 years ago. This 'new' approach will only be accepted if we understand why the twentieth-century 'biocide revolution' occurred.
Brian V. Ridout MA, PhD, AIWSC
Letting the Building Speak
An Interview with Sir Bernard Feilden
The Joumal's Patron reminisces about his professional life and interests, which became increasingly international following his much-publicised work on three English cathedrals, most notably York Minster. He reflects on the opportunities that have come his way, in England and abroad, revealing a special feeling for India, which had its beginnings during his wartime service.
Derek Linstrum DiplArch, PhD, FSA, ARIBA
Cathedral Care and the Influence
Costly cathedral works departments exist for the continuity of the building fabric so that its functions are assured. Priorities in maintenance are determined by public safety and the long-term well-being of the building, from which an operable programme is developed. This should address the needs of the building and be independent of the way funding is secured. If technical and philosophical conditions are adamantly laid down by a majority funding source, conflict is likely to arise within the routes of decision-making and conservation practice. Where funding is conditional on work being executed within a limited time scale, subtle archaeological and architectural historic detail runs the danger of being overlooked. Productivity ought not to be a feature employed in the raising of funds, but should be related to work that is necessary. Where funding is not available in sufficient quantities to guarantee a quality response to the ailments of the building, a reduced response is preferable in all cases to a poor one.
Michael O'Connor BA (Hons), PhD, AIQ
Algal and Lichen Growth
Following Chemical Stone Cleaning
Chemical cleaning methods have commonly been used to remove soiling from sandstone building facades. There has been anecdotal evidence suggesting that algal regrowth on facades can be increased following cleaning. It is shown here that both algal and lichen growths on sandstones may be substantially increased following chemical cleaning if the cleaning agents leave residues of phosphate (a nutrient normally in limited supply) in the sandstone. The growth of algae and lichens on samples of chemically-cleaned sandstones has been followed over five years. The effects of chemical residues with respect to biological growths were found to vary substantially depending on the characteristics of the sandstone. Phosphate may be chemically bound to iron compounds in sandstones. Iron-rich sandstones can therefore retain more residual phosphate than iron-poor sandstones. The duration of increased algal growth was found to vary from two years (iron-poor sandstone) to over five years (iron-rich sandstone). Where the sandstone was of low porosity and algal growth was consequently slow to become established, increased algal growth could be delayed until three years following cleaning. Lichens appeared to be stimulated by lower amounts of phosphate, and increased lichen growth was found to be of longer duration than increased algal growth. Biological growths can be disfiguring, may encourage soiling and some are capable of causing damage to stone. These results indicate that phosphate-bearing chemical cleaning methods should be used with caution on porous stone types in situations where biological growths could cause problems.
Maureen E. Young BSc, MSc, PhD, FGS
Urban Conservation Policy Development
Character Appraisal and Analysis
This paper addresses the widespread concern regarding the need to achieve a reconciliation between the desire to conserve our historic cities and the pressures for change that they face. It considers the nature of the recent responses to this situation and concludes that they can be criticized both conceptually and practically. An alternative approach drawing on techniques of urban morphological analysis is suggested and demonstrated using a case study of Chester city centre. This focuses on an analysis of three-dimensional urban form and the interacting social, economic and historical processes involved in its generation. Whilst testing and refinement of this postulation is required before its use in practice might be considered, the benefits of adopting such a structured and rational approach should be considerable.
Andrea Mageean BA (Hons), BP1, PhD (Man), MRTPI
Donhead Publishing 2013