Jason Wood

Clear, accurate records of historic buildings, their condition and the conservation work carried out are essential.

Lancaster Castle: photogrammetric surveying of the exterior walls of the 13th century Witches' Tower for Lancashire County Council in advance of repairs and refurbishment.

A record of a building or site is an essential aid in the planning and implementation of conservation projects. A good record enables better analysis and interpretation of the historical and archaeological resource preserved in every old building and sheds light on the processes of development and decay. A poorly understood resource cannot be conserved, protected, or managed effectively.

For repair and maintenance programmes it is often necessary to document both the original state of the object being conserved and the conservation process itself to provide a record, particularly where a component or structure is deconstructed, repaired and then reassembled as part of the conservation process.

Known as 'intensive' record making (as opposed to 'extensive' record making which is a more descriptive assessment), this type of documentation should be considered indispensable in all conservation work, and the costs involved should be treated as a legitimate element of the project budget. Indeed, grant aid and planning consent for works to historic buildings and monuments may be conditional on recording and understanding.

Planning Requirements
Provision for record making at nationally important sites such as scheduled ancient monuments, cathedrals and other Grade I or II* (Grade A in Scotland) listed buildings, is relatively well established in the United Kingdom through the procedures operated by the relevant national conservation bodies. Following the publication in 1994 of the Government policy guidance PPG 15 Planning and the Historic Environment, the importance of recording for all classes of listed buildings was reinforced and formally integrated into the English planning process. Under this guidance the new provisions now require that alteration and demolition work affecting listed buildings is assessed prior to planning decisions, and "exploratory opening up" can now be required where the local authority suspects that hidden features such as fire places, panelling or wattle-and-daub partitions may be affected (para. 3.24). If appropriate, applicants may be required to arrange "suitable programmes of recording of features that would be destroyed in the course of the works" (para. 3.23). Thus developers are expected to assess and justify the impact of their proposals by making provision for record making, and demonstrating an understanding of the significance of the architectural or historical interest of the building and its setting.

Documentary Research
Preliminary desk-based research should be undertaken to assess any relevant documents relating to the building and its environs. There is little point in duplicating work; relevant information should therefore be referred to or appended to the final report. Sources may include both primary and secondary written accounts, early maps, photographs and drawings or prints, and particularly any survey records dealing with past works of repair. Where appropriate, oral testimonies should be obtained from any current or former owners or tenants, and transcripts of the interviews made.

Survey for Conservation Works
A variety of different methods, equipment and related software packages are available to capture, manipulate and output survey data. The choice of the most appropriate and reliable methodology will depend on the scale, accuracy and level of recording required.

Photographic and instrument surveys are essential for large-scale recording programmes and for recording all but the most simple structures. Options include conventional and rectified photography which record dimensions in a single plane, and three-dimensional recording using photogrammetry. Photography and photogrammetry enable fine details to be recorded such as decorative embellishments or the shape of each stone and its surface markings. For rectified photographs the plane of the film is aligned to produce an image in which all parallel lines on the building or structure remain parallel, thus 'rectifying' the divergence of lines in perspective. This enables details to be reproduced to scale, and each photograph should include a rule or measuring staff. A mosaic of detailed shots may be assembled to create an entire elevation, and oblique views may be used to give some idea of depth. However, the technique remains essentially two-dimensional, providing useful information to supplement (but not replace) more precise measurement.

Photogrammetry provides more detailed information by recording 'stereo-pairs' of photographs using cameras with near distortion-free lenses. A stereo-pair consists of two photographs with the same area of elevation being imaged on each. From this is established a three-dimensional stereo-model or photographic replica in miniature of the original. The stereo-models can be digitised and scaled against measurements taken on site ('control' data) to produce accurate drawings for use with CAD (Computer Aided Drafting) software. The recent development of high resolution digital cameras simplifies the process, with wider applications for all aspects of record making, ensuring greater accuracy, security, flexibility, and economy.

Instrument surveys are typically undertaken using a total station which consists of a theodolite incorporating an electronic distance meter. Distance measurement is obtained by analysis of an infra-red beam reflected off a small prism held on the point of detail. The facility enables the capture of digital, three-dimensional data, logged on a small computer attached to the total station. Specialist survey software then enables the formatting of the data for transferral to a CAD system for manipulation into working drawings. Both this method and photogrammetry are invaluable for measuring remote objects or points which might otherwise only be reached with scaffolding. However, whichever method is chosen, the survey data will require field verification before final drawings can be produced.

Recording and Analysis
The different types of drawn, photographic, and written records for a major building conservation project include:

• base records (plans, elevations, cross-sections, and details)
• intervention records (before and during works)
• analysis and interpretation records (material type, surface finish, building periods, construction phases, occupational detail, and evidence for abandonment, demolition, reconstructions, and projections).

Records made before work commences may be required for selected areas of fabric to serve as an aid to rebuilding. Where, for example, it is necessary to deconstruct the timber frame of a listed building to repair decay, or where partial demolition of its masonry to remove rusting metal cramps cannot be avoided, consent for the work will usually be conditional on the production of accurate records. These records will be essential for reassembling the structure. Particular attention should be paid to such hidden features as carpentry joints, setting-out lines, moulding profiles, inscriptions, tooling, nail positions, masons' and carpenters' marks, and graffiti.

Further records will be required to document the repair and conservation work and the finished result, so that it is clear which elements are original. Such documentation allows repairs, alterations and preventative measures to be monitored, and any recurrence of deterioration may be identified more clearly as a result, allowing further action to be taken immediately. Where repairs are no longer obvious, for example, where original and repaired areas have been painted over or gilded, photographic records backed up with precise measurements may be the only way to identify which elements are new. If this work has to be redone, accurate and comprehensive records will be vital.

Scope and Level of Recording
The scope and level of recording will be dependent on a number of factors, including relevant planning policies and research agendas, the type and complexity of the building, site logistics, and the nature of proposed works or potential threats. In some the resources available may be limited, not only where ownership is private, but increasingly with public ownership also. It should be emphasised, however, that in most instances an initial assessment is not an expensive exercise and can be well worthwhile for the applicant and local authority alike, assisting in both the formulation of proposals and in obtaining consent. Assessments may also lead to greater understanding of the structural and material performance of the fabric, thus avoiding irrevocable damage and allowing appropriate preservation.

Recording programmes must be carefully tailored to the particular circumstances of each project and the overall objective. Ideally therefore, strategies should be developed in advance of works and in conjunction with all the other professional groups involved. Clearly not all structures need to be recorded in the same detail: different circumstances will demand different responses. Levels can range from comprehensive recording of complex buildings and their environs, to selective recording of structures of more regular or repetitive construction, concentrating on those elements which are affected by proposals or which are particularly vulnerable.

Standards and Guidance for Record Making
With the increased emphasis on record making within PPG 15, there is a need for information on these various processes to be made available to local authorities and practitioners, so that common standards can be developed. Accepted guidelines for recording need to be established and a range of relevant extensive and intensive recording procedures and planning scenarios needs to be made available to illustrate good development control and building recording practices.

The increasingly important role of record making offers the prospect of greater integration between those bodies responsible for the protection and management of the historic built environment, and improved links within the planning, conservation, architectural, and archaeological professions. It is only by working in close partnerships within multi-disciplinary teams that the historical and archaeological value of buildings and sites can be fully appreciated and preserved.

Further Reading

• Andrews, D, Blake, B, Clowes, M, and Wilson, K, 1995, The Survey and Recording of Historic Buildings and Monuments. Oxford, Association of Archaeological Illustrators and Surveyors
• Buchanan, T, 1983, Photographing Historic Buildings for the Record. London, Her Majesty's Stationery Office
• DOE/DNH, 1994, Planning and the Historic Environment, Planning Policy Guidance Note 15, London: Department of the Environment/Department of National Heritage
• EH/CFCE, 1995, Cathedrals Fabric Records, London, English Heritage/The Cathedrals Fabric Commission for England
• ICOMOS, 1990, Guide to Recording Historic Buildings. London, Butterworth
• IFA, 1995, (Draft) Standard and Guidance for the Archaeological Investigation and Recording of Standing Buildings or Structures. Birmingham, Institute of Field Archaeologists
• Letellier, R, 1994, (Draft) Recording, Documentation and Information Management Guidelines for World Cultural Heritage Sites Rome, ICCROM
• RCHME, 1991, Recording Historic Buildings: A Descriptive Specification (2nd ed), London: Royal Commission on the Historical Monuments of England
• Rodwell, W, 1989, Church Archaeology London, Batsford
• Swallow, P, Watt, D, and Ashton, R, 1993, Measurement and Recording of Historic Buildings. Donhead, Shaftesbury

• Wood, J, (ed.), 1994, Buildings Archaeology: Applications in Practice Oxford, Oxbow Books

IFA Buildings Special Interest Group
The Buildings Special Interest Group of the IFA exists to further awareness of the methods and practice of archaeological work on buildings and of the value and importance of recording and analysis of buildings in advance of development, particularly within the construction industry and local government.

To have your name added to the Group's mailing list please advise the membership secretary, Janet Miller, Gifford and Partners, Carlton House, Ringwood Road, Woodlands, Southampton SO40 7HT.