The online resource for the historic environment

3.04 Investigation and survey

To assist your understanding of this Unit see BS 7913: 2013:
Section 4: "Heritage Values and Significance"
Section 5: "Using Significance as a Framework for Managing the Historic Environment"
Section 6.3: "Assessment of performance and pathology"

“In order to manage the historic environment effectively we need to know its condition and how it is changing” Power of Place.
English Heritage (2000)

“A thorough understanding of the historic development of a building is a necessary preliminary to its repair.
…in addition to analysis the detailed design of repairs should be preceded by a survey of… structural defects and an investigation of the nature and condition of…materials and…the causes and processes of decay.”
English Heritage

“Before the design and specification of repairs can be determined it is essential to fully assess the nature and condition of the structure and building materials and the causes of defects to these factors in an historic building… Any exploratory investigation… should be carried out with the greatest care in order to prevent further damage.”
Pickard, R. D. (1996)

"[You should demonstrate ]… an ability to adopt an analytical and self-critical approach in the search for defensible solutions to …problems… It is sometimes better in conservation terms to do nothing or nearly nothing.“
Earl, J. 2000

Simply because an asset is old and does not comply with modern standards, or technology, does not imply that it has limited value. All too often our historic environment is adversely affected by inappropriate intervention based on the premise that it does not comply with modern standards.

Why is there a need to investigate prior to intervention? What, in broad terms should be the purpose of investigating and surveying a site, monument or ensemble (SME)?

In simple response it is to establish clarity of understanding about the SME, its cultural significance and processes of decay to ensure that best possible or optimal solutions to intervention are proposed in order to protect significance.

The asset will, over the course of its existence, have been subject to interventions of all kinds. Some will have been damaging to the asset, its fabric, structure and cultural significance but all might have significance in terms of its historical record - its palimpsest. Therefore, care should be taken in assessing previous interventions to ensure that any proposed new work does not adopt a subjective or conjectural approach in respect of previous periods of development. Knowledge and understanding is probably the best tool in structuring appropriate change rather than inappropriate intervention. Therein lies the most persuasive argument for a pre-intervention investigation in order to inform work and to identify and protect significance.

“Archaeology can preserve intimate pictures of the everyday lives of those who shaped the places we occupy today. This irreplaceable resource represents the endeavours of past communities and yet it is of relevance to us and will continue to have relevance for future generations.”
Development & Archaeology in Historic Towns & Cities. Historic Scotland 2005

Increasingly within the investigative process the role of the building archaeologist has gained importance in clarifying the historical progression of an asset’s development. Traditionally the role of the archaeologist has been associated as a sub surface discipline based on stripping down layers to gain understanding. Advances in technology has allowed the process of archaeological analysis to be undertaken without loss of overlying layers of development, use of photomodelling software and laser measuring techniques has facilitated three dimensional deconstruction without physical damage to historic fabric. Such technology is extremely useful in trauma situations such as fire damage. In the fire that occurred in the Cowgate of the Old Town in Edinburgh, technology was used to accurately analyse the burnt structure and facilitated a detailed clarification of historic progression that informed interventive processes and guided understanding of both the damage and helped with identification of important structural features that might otherwise have been lost in the reconstruction process. Such information coupled with detailed documentary evidence and research has proved invaluable in the post trauma evaluation process of one of Edinburgh’s most historic sites. The principles of archaeology, based as they are in detailed, even microscopic evaluation of evidence will assist the process of understanding a site’s significance and historical progression.

The adoption of point cloud laser scanning of interior and exterior detail can provide a greater understanding of the fabric, spaces and forms in consequence of the accuracy it provides.

An exhibition piece of stonework clearly showing masons’ Marks, used to assist assembly of the completed masonry.
The role of the archaeologist in recording and analysing historical development has increased over recent years, particularly in area redevelopment when otherwise historic progression might otherwise have been lost through redevelopment.

“At the heart of any judgement about significance lies understanding. We need to know why what is there is there. We need to know how it was constructed, altered and used through time; what survives and what has been lost.”
Cossons, N, Sir. Foreword to Informed Conservation (2001)

Planning the manner and method of investigative operations should be a primary focus for you as a conservation practitioner. Much initial information may be obtained by simple observation of the asset, coupled with research of documentation and records covering the asset.

“The essential basic tools for… investigation remain good eyes, an open mind and profound knowledge and understanding of both original construction methods and historical repair techniques.”
Demaus, R.

A great deal of information may be gleaned from archives both local and national.

Consider where such documentary evidence might:
  • be sourced and,
  • be archived in respect of a Scheduled Monument in a location close to where you are

A condition survey of the asset, its fabric and structure might be a secondary action. Such survey would need to address issues of:

  • Fabric deterioration
  • Materials decay
  • Weathering
  • Assessment of structural condition
  • Prognosis of likely effects of deterioration processes

From such physical investigation and coupled with the results of the documentation research, you will be able to make informed decisions about what, if any further investigation is necessary to facilitate an informed and properly structured intervention strategy.

“Where observation is concerned, chance favours only the prepared mind.”
Louis Pasteur 1822 - 1893

You will need to be able to plan an investigative survey methodology that will have minimum effect on the fabric in order to protect significance. Any further physically invasive survey proposals must allow for the minimum damage necessary to provide sufficient information to proceed to plan intervention strategy.

Further investigation might involve specialist in the field of asset deterioration and you should be able to demonstrate an ability to determine the need for and briefing of specialist consultants.

“Non omnia possumus omnes." [We can’t all do everything].
Virgil 70 - 19 BC

In respect of an SME in your area that has been subject to a period of neglect, consider what methods might be adopted to investigate and survey the structure prior to planning a programme of rehabilitation?

Non-invasive, non-destructive methods should be adopted in all but exceptional circumstances.
You may wish to consider some of the following options:

  • Photogrammetry
  • Point cloud laser scanning
  • Thermal imaging
  • Dendrochronology
  • X-ray analysis
  • Impulse radar
  • Endoscopy
  • Ultrasonics
  • Micro-drilling
  • Damp, fungal and insect damage investigation
  • Moisture measurement
  • Measured and levelled surveys
  • Geological record search
  • Archival document search
  • Simple photography, rectified photography
  • Building archaeology

See also Demaus, R (1996) Non-Destructive Investigations Building Conservation Directory, Tisbury

What additional information might an archival search provide to assist your understanding of a site’s context and how that context has changed/developed over time.

Below are some basic questions to ask yourself to help in developing your understanding of an asset:

  • What is the cultural significance of the asset, both historical and aesthetic
  • What was the social, cultural, technological, economic and political context in which the asset was originally conceived constructed and subsequently changed and how has its importance changed/developed as a result of changes in use or appearance
  • What is the date of the asset, originally and by subsequent periods of development (and what was the date/effect of subsequent periods of development)
  • Who was the patron or original client and subsequent clients/patrons and their involvement
  • What was the original brief for the asset and any subsequent works
  • Who was the architect or designer and who built it
  • How was it constructed/altered
  • What was its original and subsequent function(s)
  • Which parts are original and which alterations
  • What are the materials and methods of construction and what is their condition
  • What is the form and style and what was its meaning
  • What was the original context and how has the asset’s landscape or setting changed/developed
  • What was the public response to the building in its original form and as a result of subsequent changes: How has that assessment/understanding changed
  • What is happening to the building in terms of deterioration and how might this be affecting significance
  • What is the structural condition and is it stable

(after Conway & Roenisch)

In light of the above, suggested format, critically assess your previous investigative methodology in respect of a project on which you have recently worked

“The more answers, and the fuller they are, the more the researcher can build up a picture of why the building came to be…the characteristics and significance…and the context in which it was produced, used and evaluated … Documents and written evidence offer insights into …but in practice much research involves a mixture of reading, searching … analysing plans and illustrations and surveying the fabric”
Conway and Roenisch 2005/

A useful source of information detailing methods and processes of investigation and recording is ICOMOS (1996) Principles for the Recording of Monuments, Groups of buildings and Site ICOMOS, Paris

“We cannot care for the historic environment, or direct resources effectively, unless we understand what it is, what its condition is and how it is changing. We need continuous, thoughtful and well-targeted research to enable us to identify significance and potential.”
Power of Place. English Heritage (2000)/