The removal of soiling from a building can be achieved using water, chemicals, poultices, lasers, and also mechanical cleaning methods. Mechanical cleaning requires the use of force using hand-held tools such as brushes, sponges, scalpels etc. or with equipment such as vacuums, or dry air-abrasion. Mechanical cleaning can be low-impact, and is often used where water or chemicals are not suitable. However, stone can easily, immediately and permanently be damaged by mechanical cleaning.
Abrasive cleaning systems direct particles onto soiled masonry in a stream of compressed air of between 1.5 and c.7bar. The systems work by Continue reading
Aerial photography, and increasingly aerial remote sensing data captured by satellite, provide a high-resolution view of the ground that can be relevant at all stages of an archaeological study, including reconnaissance, identification, analysis and, of course, as illustrations in a publication. Many new archaeological sites, especially those that survive as earthworks, have been discovered with the use of aerial photography, both from desktop studies of existing photographic records and from new reconnaissance. Aerial photography is also useful for Continue reading
“Unchallenged, the natural world soon asserts control over the works of human kind. No longer buildings, not yet wholly a natural landscape, ruins provide a specialised environment which plays host to a wide range of flora and fauna“, Sara Ferraby, Conservation of Ruins
Dublin Bay was designated as a biosphere by UNESCO in 2015 which comprises a core of the Tolka and Baldoyle estuaries, North Bull Island and Howth Head, Ireland’s Eye, Booterstown Marsh and Dalkey Island. Historic places and natural heritage are often Continue reading
The existing literature and knowledge across many disciplines, including stone conservation and heritage management, is founded on an ability to react and adapt to changing situations, based on the knowledge and experience gained through past and current events. However, both reactive and anticipatory responses to threats to buildings are largely based on the premise that the past is the key to the future. predicted rapid changes in climatic conditions anticipated throughout the 21st century, results in a situation where past events can no longer be relied upon for driving future decision-making. Many of the established truisms and work practices of stone decay, cleaning and conservation may have to be amended, altered or abandoned when confronted with new challenges.
The existing stone conservation literature is too-often centered on understanding stone deterioration and providing appropriate solutions on a very simplisitic basis. Stone conservators are focused on solutions for ‘limestone’ problems and ‘sandstone’ problems, though these are very complex materials, containing sub-types of widely varying stone properties, durabilities, and responses to soiling and new environmental conditions. As the 21st century progresses, heritage professionals will see more complex interactions between stone decay and soiling processes and changing environmental conditions. There is a need for growing interaction between heritage professionals to respond to increasingly complex future architectural conservation problems. There will be a number of key shifts, which cannot currently be accurately quantified, but can be flagged as areas of concern. These include: Continue reading
Stone in buildings is exposed to natural patterns of weathering, varying urban conditions, a legacy of repair and change, building quirks and outside events that interact in complex in complex and sometimes unpredictable ways to produce new patterns and new rates of stone decay. Stones can also have a ‘memory’ of the legacy of structural and chemical changes it has undergone since before it was quarried – legacies which can explain why stone continues to deteriorate long after air pollution levels have improved. Further, different stones react differently to different stresses, and require different solutions. A necessary part of building the knowledge to make informed decisions to conserve stone buildings is to understand why and where stone decay can and does occur.
The aim of this stone conservation research project was to gather information on the degree of degradation and erosion of stone monuments in the Republic of Ireland dating from the Neolithic through to the nineteenth century. The study examined 112 archaeological monuments in 14 counties, identifying and assessing the most significant forms of decay and impacts to stone monuments based on factual up-to-date information gathered through fieldwork and laboratory analysis. The archaeological monument types dated from the Neolithic to the nineteenth century and included megalithic tombs, cashels, Anglo-Norman castles, medieval tower houses, post-medieval buildings, and ecclesiastical heritage including churches, abbeys, round towers, high crosses and a range of smaller stone monuments including crosses, a cursing stone, leachta and grave slabs.
The most significant results and conclusions of the study are: Continue reading
The conservation of stone is one of the most complex and challenging areas in architectural conservation, involving a detailed understanding of a wide range of materials, how they respond to weathering, how they interact with other historic building materials and interventions over time, and the repercussions of maintaining, cleaning and conserving architectural and archaeological building fabric. Ireland has a particularly rich heritage of building with local stone. Historic buildings and archaeological monuments may be constructed from a wide range of stone types including limestones, sandstones, conglomerates, granites and other igneous, metamorphic and sedimentary rock types.
Detailed knowledge of Irish building stone has been developed since 1997 through desktop research, fieldwork and laboratory analyses. Analytical services to advise on the weathering, conservation and repair of stone include:
- Characterisation of Stone
- Diagnosis of Weathering and any other Deterioration
- Identification of Type and Impact of Soiling Deposits
- Sourcing of Suitable Replacement Stone
- Testing & Comparison of Conservation Treatments
- Overseeing & Monitoring Cleaning & Conservation
- Design of Replacement Mortars for Stone Conservation
- Recommendations for Conservation, Cleaning & Repair and Preparation of Specifications
Discovering Historic Fingal a Guide to the Study of Monuments, Historic Buildings and Landscapes was commissioned in Summer 2006 by Fingal County Council, in association with The Heritage Council, as an action of the Fingal Heritage Plan 2005-2010. The purpose of the guide is to provide a practical, comprehensive and user-friendly reference book to all available archaeological and architectural source material for Fingal. The concept of an area of “Fingal” begins in the early medieval period, with the land known as Fine Gall or “territory of the strangers” referring to establishment of Viking settlers. The guide is intended for a wide range of users, including the general public, professional users, those in formal education at all levels, policy and decision makers, and the wider archaeological and architectural communities.
The guide introduces the essential source material for researching the built heritage of the county including textual information, maps, photographs, illustrations, models and artefact repositories. In order to provide the necessary context, researchers are also guided towards national repositories and general sources of Irish archaeological, architectural and art historical source material which may be relevant. The guide is not intended as an exhaustive work or a bibliography, but is instead intended as a practical reference book to guide researchers to where useful information can be found.
New researchers should approach the information contained in both primary and secondary sources with a degree of caution, and develop an understanding of “source criticism”, or the strengths and weaknesses of historical material. Historical sources are not infallible, are unlikely to be wholly accurate or truthful, and researchers assessing the significance and value of source material would be wise to be aware of Continue reading
Historic graveyards provide us with landscapes of cultural, historic and natural interest, and often remain in use. Irish historic graveyards may contain a wide range of monuments such as headstones, ledger slabs, box tomb chests, allegorical sculpture and mausoleums. Many graveyards are also archaeological monuments, retaining much earlier burials and structures and so require special consideration and consents for necessary repair and conservation works.
Deterioration and weathering are inevitable parts of the history of a monument, and the principles and techniques Continue reading
This blog is now changing to become an accompaniment to my professional services website http://www.boltonconsultancy.com and should soon contain a more interesting array of case studies reflecting the range of professional work I carry out. The advice notes and information for students will continue. However, as I only give a relatively small amount of lectures and public talks during the academic year on architectural conservation and archaeology, this re-purposing of the blog will allow it to be updated more frequently and the scope expanded to include a much wider range of conservation topics.
It will therefore include discussions of conservation plans, research into stone decay, experimental work on the conservation of materials, condition surveys, heritage impact assessments, archaeological assessments, historical research, Continue reading