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Journal of Architectural Conservation

Volume 13 Number 3 November 2007

Editorial
Vincent Shacklock

Professionals engaged in the management and repair of historic fabric strive to make decisions informed by thorough surveys, analysis and planning, all underpinned by philosophies appropriate to the task. In this way risk to the building, project and client is minimized. It is worth looking at the five papers in this issue from the perspective of risk.

A large proportion of Journal readers permit, design, manage or undertake interventions intended to sustain historic buildings, structures and spaces. We all wish to believe that our building interventions are justified in philosophy, science and craft. We draw upon guidance set out by national and international conventions, professional codes of practice and so on, and we commit to keeping ourselves abreast of issues and developments relevant to our research or teaching. But professional life is never so straightforward as to deal us tasks and projects, one after the other, all well within the comfort zones of our professional or intellectual home ground. Whether we are scientists, craftsmen, architects, technologists or conservation officers, the next project to appear at our door can present complex issues of philosophy, technology or context, capable of resolution only with the benefit of research and reflection. Of course, one might have undertaken something very similar elsewhere, and with very good results, but the vagaries of historical architecture usually conspire to ensure each feature, material etc., almost certainly, causes shifts in plan as the project unfolds.

There are seldom, if ever, projects where the practitioner can rely entirely on past experience for guidance. Some detail, material, disturbing historical complexity, or specific site feature inevitably requires the amendment or modification of a previously tried method, device or technique, or the creation of a new process, tool or rationale. It is only in this way that practitioners can satisfy themselves that they are giving their utmost in search of a measured and justifiable solution. Almost every intervention carries risk and uncertainty. Despite superficial similarity, the different locations, histories, materials and contexts of historic buildings can define a contract so that it is unlike any other. Far more than with recently constructed buildings, each time we intervene, we do so with uncertainty. Historic buildings are replete with risk.

Our first paper, courtesy of Dr David Yeomans, ‘Appropriate Technologies for Conservation’, takes a critical look at some conservation principles which have emerged over time, becoming accepted by many as the foundations of repair strategy. Helpfully timed to inform the debate subsequent to English Heritage’s recent consultation paper, ‘Conservation Principles’, I find his observations helpful and constructive. Some readers will take issue with certain of his contentions, but this is an intended purpose of publication and scholarly debate. A civil engineer with a PhD in structural carpentry, he asks us to examine notions relating to conservation/repair philosophy, and draws upon well-chosen materials and cases. He argues that any principles adopted should be appropriate to the technology of construction, partly to preserve the integrity of the original design, and partly for sound practical reasons. I admire the paper for its provocativeness as well as its clarity of observation.

In this issue, John Earl and John Muir take us through a significant restoration of the Grade II*, Moderne/Art Deco Apollo Victoria Theatre, London, which, for reasons peculiar to the economics of the theatre industry, had to be compressed into a frighteningly short, sixteen-week period. Designed by Ernest Wamsley Lewis and Gaumont’s in-house architect, W. E. Trent, the theatre received approving comment in the architectural press following its opening in 1930. The foyer was dressed in black, red, pink, emerald and jade with burnished aluminium leaf. With its even more spectacular auditorium, the building as a whole was a work of startling freshness and originality. Needless to say, countless alterations and additions occurred in the decades that followed, including regrettable obliterations by overpainting, removal of decorative features, addition of ever more set lighting with its associated paraphernalia, and unsightly attempts to modify acoustics.

The particular fascination in this case lies in the approaches to project management that were essential. A theatre is either working or ‘dark’ and, in this case, economics demanded no more than sixteen weeks to the next rise of curtain. This short period, through the closest of cooperation between the local council, architects and contractors, including the adoption of novel procedures in relation to listed building consents, saw remarkable achievements in the conservation and restoration of features and decoration.

Our third paper, ‘Roman Cement: Stucco and Decorative Elements, a Conservation Strategy’ by David Hughes, Simon Swann and Alan Gardner, is the second half of the two-part review from the March 2007 issue. The writers, whose coming-together appears to have been courtesy of connections through the Building Limes Forum, appear admirably suited to the project for which they have been funded. An academic, a practical conservator and a materials specifier have worked with the support of an enlightened research funding body on a project where there is a clear need for practical research, and huge potential benefits to be gained. How unusual this research team must have first appeared, and how admirable to see the end use of research investigation so well reflected in the team’s make-up. A risk often associated with research at this level – that science is separated from practicality – has been managed from the outset. We must still wait a number of years for such testing to yield quantifiable results, but this is a research funding exemplar and the benefits might one day turn out to be substantial.

Although thatch fires are not a common occurrence in the UK, there are 50–55,000 thatched properties, nearly half of them listed. While admittedly rare, a fire outbreak in thatch is nearly impossible to extinguish, and so owners and other stakeholders must properly understand the risk. Fire is the greatest single threat to a thatched building, and authors Roger Angold and Marjorie Sanders have set out for us an informative update in ‘Managing Fire Risk in Historic Thatched Buildings’. There are 70–100 thatch fires each year, most often causing the total loss of roof material and huge additional repairs (averaging £200,000 per building). A majority of these fires are chimney-related, and an increasing number are specific to multi-fuel appliances. Since thatch fires are notoriously difficult to contain once started, it is essential that prevention measures be well understood. The paper explores the causes of thatch-ignition, considers heat conductivity, discourages multi-fuel appliances, and comments on the practice of ‘over-thatching’ of roofs so that roof-depth becomes very great, with additional implications for risk.

The final paper, by Dr Pance Velkov, ‘Preserving Historic Churches and Monasteries in the Republic of Macedonia’, brings into focus (notable exceptions apart) the continuing relative disparity between the capacity of Western and Eastern European counties to cope with investment needs in historic fabric. With the collapse of Yugoslavia, Macedonia became an independent nation, its remarkable sacred heritage escaping as a uniquely well-preserved whole, reflecting the country’s multicultural character. Unlike other communist countries, Macedonia evaded the wilful destruction of religious heritage during the communist period. Here, some of the most valuable frescoes in the world are found in churches and monasteries dating from the Byzantine and post-Byzantine periods. This paper considers the alarming threat to these frescoes, many of which are inadequately documented. Impoverished and caught in a peculiarly slow process of transition from communism, this heritage is under severe threat. It is painfully ironic that the most likely cause of widespread fresco deterioration is the well-meaning replacement of roofs of these churches in the communist period. These conservation measures, using concrete, steel and other ‘superior’ materials, are now apparently causing damaging humidity shifts in summer and winter. Clearly, there had been no risk assessment. Why is this so unsurprising?

Vincent Shacklock

Appropriate Technologies for Conservation
David Yeomans

Conservation principles rarely consider the technology of either the historic artefact itself or of the technologies to be used in conservation. This paper argues that the principles adopted should be appropriate to the technology of the construction, partly to preserve the integrity of the original design, but also partly for sound practical reasons. This is particularly true of more recent and somewhat transient technologies. It also considers the advisability of using some sophisticated techniques to stabilize existing structures when more traditional repair methods, even perhaps including rebuilding, might be more appropriate. This requires a more flexible approach and a clearer evaluation of the historical significance of the existing fabric. Moreover, for sensible judgements to be made and appropriate methods of repair to be selected, it is necessary that the technologies of construction be understood.

David Yeomans BSc(Eng), PhD, AIWSc

David Yeomans practices as an engineer specializing in the repair of historic timber structures, teaches regularly on the MSc in Timber Building Conservation at the Weald and Downland Museum and is secretary of the International Committee for the Analysis and Restoration of Structures of Architectural Heritage (ISCARSAH).

The Apollo Victoria Theatre
Conservation Against the Clock
John Earl and John Muir 

The Apollo Victoria Theatre is an architecturally outstanding work of its time. With a seating capacity of 2572, it has been in recent years one of the most successful musical houses in the West End of London, but its original architectural and decorative character had become severely eroded over the years. This paper describes how conditions peculiar to theatre work dictated that major restoration works, from confirmation of instructions, through detailed planning to execution, had to be completed within a rigidly defined period of 16 weeks, allowing no scope for overruns or failure to deliver.

John Earl FSA, MRICS, IHBC, FRSA

John Earl, author of Building Conservation Philosophy (Donhead, 2003), worked from 1956 to 1986 with the LCC’s, later Greater London Council’s, historic buildings division and later became director of a statutory body, the Theatres Trust, retiring in 1995. He is now a conservation consultant working exclusively on historic theatres.

John Muir RIBA FRSA

John Muir has worked as an architect in private practice since 1964 and for the last 25 years has specialized in theatre work, primarily in the commercial sector. He served as a trustee of the Theatres Trust from 1995 to 2004.

Roman Cement

Part Two: Stucco and Decorative Elements, a Conservation Strategy

David Hughes, Simon Swann and Alan Gardner

Roman cement had a short period of significant use in comparison to lime and Portland cement. Despite this, there is a legacy of fine buildings about which conservators need to be informed. Part One of this paper (published March 2007) provided a brief history of the material, its characteristics and the mortars used for stucco and cast decorative elements, with due recognition given to the surface finishes which were required. In this paper, a conservation strategy is proposed which includes reference to the EU funded ROCEM project through which small-scale production of Roman cement has been recommenced. It is determined that further research is required before the impact on the consolidation of the historic fabric from the use of silicate paints can be fully understood.

David C. Hughes BSc (Hons), PhD

David is a senior lecturer in construction materials with particular interests in mortars using cements, limes, hydraulic limes and pozzolanas. He is currently investigating the use of rapid prototyping technology for the production of moulds to yield cast elements from existing decorations and historical drawings.

Simon Swann BA (Hons), ACR

Simon is an architectural conservator specializing in mortars, plasters, stucco, stone and related materials. He has been involved in several major conservation projects involving the conservation of Parker’s Roman cement and was a member of the ROCEM project. 

Alan Gardner BSc (Hons), MRICS, SPAB Lethaby Scholar

Alan is a chartered building surveyor in private practice, accredited in conservation, who has been involved in providing consultancy advice, specification writing and contract administration on a number of Roman cement repair and redecoration projects.

Managing Fire Risk in Historic Thatched Buildings

Roger Angold and Marjorie Sanders

Every year, between 70 and 100 thatched properties will experience a serious fire. In addition to the irreplaceable loss to the built heritage, the financial cost of reinstatement is now in excess of £200,000 per building on average. The majority of thatch fires are chimney related, and are most often associated with the installation and use of modern multi-fuel appliances. The potential for a fire is entirely dependent on understanding and managing the risks during the design and installation process, and on the subsequent usage patterns of appliances. There are a number of risk minimization construction strategies that can be used in old properties that will not compromise conservation principles. However, when a fire does occur, it is important that firefighters are familiar with the pattern of fire spread in a thatched roof, and know how to recognize the roof construction details designed to protect the rest of the property. Unfortunately, once started, thatch fires are almost impossible to control; therefore, prevention is essential, as if one relies on detection, it is almost always too late to save the property.

Roger Angold PhD, MA, BSc, CBiol, MIBiol

Marjorie Sanders MPhil, CBiol, MIBiol, Churchill Fellow

Between them, the authors have experience in botany and cereal science, agriculture and food research. For the past 15 years, they have been active leaders in both academic and practical research into the major causes, management and control of fires in thatch.

Preserving Historic Churches and Monasteries in the Republic of Macedonia

Pance Velkov

Some of the most valuable frescoes in the world can be found in the churches and monasteries in the Republic of Macedonia. Painted mostly in the Byzantine (eleventh to fifteenth centuries) and post-Byzantine periods (fifteenth to eighteenth centuries), these frescoes are now under threat, presumably due to the fact that the original roofs covering the churches were replaced by modern ones. The new roofs, made of aggressive materials such as cement mortar and reinforced concrete, have very low air permeability and do not allow sufficient drying of the fresco layers during the humid periods in winter and cause over-drying of the fresco layers during the hot and dry summer periods. This phenomenon is believed to be the main cause for the frescoes’ degradation. This study examines some recent interventions to Macedonian church buildings and what appears to be consequential damage to the fresco paintings, which in some cases is already irreversible. It also proposes possible approaches which could help to save this important element of world heritage and preserve it for posterity.

Pance Velkov PhD

Pance Velkov  is a permanent member of the committee of experts on heritage education of the Council of Europe, and president of the Macedonida Foundation for Heritage Education, Promotion and Valorization.

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