Contents:

Limes and Lime Mortars - Part Two David Carrington and Peter Swallow

St John's Cathedral, Brisbane: The Completion of Pearson's 'Last and Greatest Work' Arthur J. Grimshaw

Reconciling Authenticity and Repair in the Conservation of Modern Architecture Susan Macdonald

A Field Investigation of Algal Growths and Biocide Efficacy on Sandstone Buildings and Monuments D.C.M. Urquhart, M.E. Young, R.D. Wakefield, K. Tonge and K. Nicholson

The Green Way out of the Water: Issues Raised by the Conservation of the Luisenstadtischer Kanal in Berlin Volker Schirner and Judith Roberts

Editorial
International Conservation
David Watt

At a time of rapid and widespread change, it is all too easy to lose sight of those deserving causes that warrant attention and the allocation of scarce resources, amid the clutter and confusion of late twentieth-century living. Conservation, like so many other activities, is under pressure to deliver a product that will satisfy the twin masters of economic development and cultural tourism. It is therefore reassuring to see that the growing awareness of international issues coupled with the increasing level of co-operation between countries and organizations is informing the ways in which we approach our own problems. This, in time, may help to increase our perspective towards long-term solutions.

Following the review of traditional lime production and preparation given in the first part of Limes and Lime Mortars (Vol 1, No 3), David Carrington and Peter Swallow have turned their attention to the practical issues of slaking and preparing limes, selecting appropriate sands, and gauging and mixing traditional lime-based mortars, renders and plasters. What makes this paper so valuable is the clear and authoritative manner in which the authors deal with the basic processes and the current issues of hydraulic limes, cements and pozzolanic additives. The final section, concerned with the determination of appropriate repair mortar compositions, provides practical instruction through three differing case studies.

The work of the Masonry Conservation Research Group at the Robert Gordon University in Aberdeen will already be known to those concerned with the care and conservation of masonry structures. In A Field Investigation of Algal Growths and Biocide Efficacy on Sandstone Buildings and Monuments Dennis Urquhart and his colleagues provide clear and useful guidance on the characteristics of algal growths, their effects on various sandstones, and the results of recent tests concerned with the use of biocides.

It is a measure of the way in which conservation (whether of the built or natural environments) brings people together and fosters links across the world that we have a paper from Australia concerned with the work of the nineteenth-century English architect, John Loughborough Pearson, and the building of a cathedral in Brisbane. The Very Reverend Arthur Grimshaw, Dean of Brisbane Cathedral, has provided a paper that is alive with the meaning of great architecture in the lives of those who use this building. In it he tells the story of its construction in a way that does justice to Pearson's 'last and greatest work'.

In The Green Way out of the Water Volker Schirner and Judith Roberts provide a fascinating insight into the practical and philosophical issues raised by the conservation and restoration of the Luisenstadtischer Kanal in Berlin. It is clear that there is much to be learnt from the ways in which this work has been organized and implemented, particularly for countries or regions seeking to unite, or reunite elements of their history and culture.

Susan Macdonald's paper entitled Reconciling Authenticity and Repair in the Conservation of Modern Architecture provides a timely and thought-provoking look at the problems to be faced in conserving our twentieth-century heritage. Increasing concern for the damage done to the design statements and material challenges of modern architecture have fostered an important international debate. Papers such as this, and the English Heritage Modern Matters conference from which it has been drawn, are essential in raising the awareness of those who own or look after such buildings.

Finally, it is appropriate in this particular issue to acknowledge the support and assistance of the Getty Grant Program in the publication of the Journal. This comes in recognition of its value to international conservation.

Limes And Lime Mortars - Part Two
David Carrington and Peter Swallow

This paper deals with limes and lime mortars and is presented in two parts. Part One (Volume 1, Number 3) identified the sources and qualities of limes in England and Wales, and traced the burning of lime, the development of kiln design and the search for hydraulic cements from ancient times up to the end of the nineteenth century. Part Two examines the slaking and use of lime for mortar mixes and compares the qualities of lime-based mortars with composition and ordinary Portland cement mixes. General advice is offered on mortar mixes for the repair of historic fabric and three case studies are provided to illustrate the importance of determining appropriate mortar compositions for repair work.

David Carrington BSc, MA
David Carrington trained initially as an archaeologist and later developed an interest in architectural conservation. He is a Senior Conservator and Contracts Manager with Hirst Conservation, based at Laughton in Lincolnshire.

Peter Swallow Dip Surv, Dip Cons Arch, FRICS, FBEng, FRSA
Peter Swallow is a chartered building surveyor and engineer. He is Professor of Building Surveying and Head of the Department of Building Surveying at De Montfort University, Leicester.

St John's Cathedral, Brisbane

Arthur J. Grimshaw

Dean Arthur Grimshaw of Brisbane reflects on the continuing task of building a Neo-Gothic cathedral in the antipodes. The project, initiated more than a century ago, is now in the process of being completed.

The Very Reverend Arthur J. Grimshaw BA, ThL
Arthur Grimshaw, born 1933, was for five years a chorister in the William Butterfield cathedral of St Paul's, Melbourne. He was ordained deacon at the same cathedral in 1957 and priest in 1958. Since 1985 he has served as Dean of Brisbane, and was the initiator of the present phase of completion, which was set in motion in 1987.

Reconciling Authenticity and Repair in the Conservation of Modern Architecture
Susan Macdonald

This paper is a precis of that presented at the Modern Matters conference organized by English Heritage in October 1995. The conference, subtitled Principles and Practice in Conserving Recent Architecture, sought to address some of the current issues faced by those involved in the care and conservation of buildings from our twentieth-century cultural heritage.

The present paper attempts to outline some of the apparent Philosophical difficulties raised by the conservation of modern buildings, which arise largely from specific practical or physical issues. The current interest in authenticity in relation to the conservation of historic buildings is particularly relevant for buildings from our more recent past, forcing us to reassess existing principles and approaches. It is modern architecture's characteristic utilization of new technologies, together with the use of innovative materials and construction detailing, that makes the reconciliation of material and design, or aesthetic authenticity, problematic.

Increased understanding of the many technical issues and the development of economically viable repair techniques will clarify some of the controversial philosophical issues. Changing attitudes to our twentieth-century heritage will, no doubt, ensure that current opposition to the retention of important modern buildings will subside as understanding and appreciation for modern architecture grows. Investigating solutions to some of the key problems of deterioration can also inform current building practice and assist in achieving sustainable development in the future.

The proceedings from the Modern Matters conference will be published in full by Donhead Publishing and will be available later this year.

Susan Macdonald BSc (Arch), BArch (University of Sydney), Architectural Conservation Cert (ICCROM, Rome), RIBA
After completing her architectural studies at the University of Sydney, the author practised as an architect, specializing in architectural and landscape conservation. Since 1988 she has worked in various conservation practices in the United Kingdom, including Peter Inskip and Peter Jenkins, Architects, before joining the Architectural Conservation Branch at English Heritage in 1994. The author completed the architectural conservation course at ICCROM in 1991 and is currently completing her MA in conservation studies through the ICCROM/Institute of Advanced Architectural Studies, York, joint programme.

A Field Investigation of Algal Growths and Biocide Efficacy on Sandstone Buildings and Monuments
D.C.M. Urquhart, M.E. Young, R.D. Wakefield, K. Tonge and K. Nicholson

This paper reports on recent research, sponsored by Historic Scotland, which investigated the problem of algal growth on sandstone buildings and monuments in Scotland and the efficacy of various biocides under field conditions. Factors influencing the growth of algae on building stone were assessed and related to a field survey of urban buildings and historic properties in mainly rural locations throughout Scotland. The work compared both cleaned and uncleaned stone facades. In parallel with the field survey work, and forming the major part of the investigation, a series of experiments were set up in the laboratory and in the external environment to determine the efficacy of a selected, representative range of biocide treatments when applied to six different sandstones. To determine biocide efficacy, a specially designed field exposure test rig was developed on which the sandstone samples were exposed. The test results show that there are considerable differences between the effective lifespans of the different biocides tested. As a result of this work it is possible to predict the susceptibility of sandstone structures to soiling by algae, and to offer guidance to those charged with the care of historic property on the efficacy of biocide treatment.

Dennis Urquhart BSc, MSc, FCIOB
Building scientist, Director of the Masonry Conservation Research Group and Reader in the School of Surveying. Has extensive experience in the direction and conduct of research in the field of masonry conservation, with recent work including biological growths on and the biocide treatment of sandstone, cleaning of granite, stone cleaning, stone decay and easy access to historic properties.

Maureen Young BSc, MSc
Geologist, geochemist and Research Associate in the Masonry Conservation Research Group, Faculty of Design. Currently conducting research into biocide applications to sandstone.

Rachael Wakefield BSc, PhD
Microbiologist and Research Associate with the Masonry Conservation Research Group, based in the School of Applied Sciences. Currently working on research into biological decay mechanisms of sandstone.

Kenneth Tonge ARCST, PhD
Chemist and part time lecturer (formerly senior lecturer) in the School of Applied Sciences.

Keith Nicholson MSc, PhD, CChem
Geologist, geochemist, Reader in Environmental Geochemistry in the School of Applied Sciences and senior member of the Masonry Conservation Research Group.

The Green Way out of the Water

Issues Raised by the Conservation of the Luisenstadtischer Kanal in Berlin

Volker Schirner and Judith Roberts

This paper looks at the Luisenstadtischer Kanal in Berlin as an example of historic park and garden conservation in urban areas. The history of the site and the development of the surrounding area is described and the practice of conservation in Berlin following the collapse of the Wall is reviewed. From the starting point of this case study, some of the broader issues of park and garden conservation are examined and the need for area-wide strategic planning is assessed.

Volker Schirner Dipl Ing
Volker Schirner is landscape architect at the Landesdenkmalamt of Berlin. He leads projects dealing with the research, archaeological investigation and restoration of Berlin's historic squares, public parks and gardens.

Judith Roberts BA(Hons), MA (Conservation Studies), PhD
Judith Roberts is Senior Research Fellow and Associate Director of the Centre for Conservation Studies at De Montfort University, Leicester.