Building archaeology is the discipline of reconstructing the history of existing buildings using direct observations. Archaeologists can trace a structure’s past by analysing data such as materials, building techniques, how elements connect with one another, and so on. In a similar way to architectural conservation, building archaeology uses scientific and analytical techniques to describe, assess and date structures.
The main difference between building and excavations archaeology is that the latter requires invasive digging procedures in order to make visible the sources of data, whereas on the whole, a building can be analysed by observation of its exposed surfaces, materials and building techniques without impacting upon the structure itself.
Establishing timelines may not always be the main point of interest for the archaeologist, but it may be necessary to understand dates to obtain an accurate and thorough description of a building’s development, as well placing data within some kind of historical context, which can help identify explanations for the building.
Some of the methods that an archaeologist can use are set out below.
The representation technique is based on the ‘stratigraphical unit’ (SU) concept, that is, a part of the building that was the result of a single action of construction. Archaeologists try to pinpoint ‘positive SUs’ (additions) and ‘negative SUs’ (deletions) on the timeline of the building.
Chrono-typology is a dating method based on identification of architectural features from different historical periods rather than on the building itself. It involves using a reference database that assists with the identification of particular construction elements and associating them with the relevant period.
- Establishing the geographic context for the research.
- The filing and indexing of a large number of items of a particular architectural element.
- Classification of the element’s distinctive features.
- Identification of the group of instances in the building that share the same distinctive features.
- Identification of the date period for the group itself.
Dendrochronology, also known as ‘tree ring dating’, is a technique that involves reading the sequence of ring thickness values of a timber element. This can identify the date that the timbers were felled.
A tree gains another ring each year as it grows, with the thickness depending on the amount of growth. All the same trees in a region are likely to display the same chronological growth pattern. Therefore, by plotting the relative thickness of these rings, a clearly identifiable sequence of variations may emerge which can act like a date stamp for each period.
The advantage of dendrochronology is its objectivity. Where analysis results in a clear match with the master chronology the results are completely accurate and reliable.
Rectified photography is a method of recording a high level of detail on flat objects. The effects of distortion as a result of perspective are removed, and the image scaled upon one or more principal planes of the object.
Equipment required includes a compact digital camera, perhaps tripod-mounted, and a tape measure; or more specialist distortion-free cameras with high quality lenses, measured control points and dedicated software.
Each photo should be taken square on to the object, with the effects of perspective removed if possible by shifting the lens accordingly. Effort must be made to work in good lighting conditions, as shadows can result in a loss of information.
Surface areas requiring repair or conservation can easily be measured and calculated from the images. For example, rubble-built walls can be costly to have drawn stone-by-stone, but individual stones will be clearly visible in a rectified photograph and areas requiring repointing, consolidation or replacement can be marked up on the image and measured.
Photogrammetry is the practice of obtaining information about physical objects through the process of recording, measuring, and interpreting photographic images. It is most commonly associated with the production of topographic maps through aerial survey, but may be used in any situation that requires accurate three-dimensional data or precise drawings, and is ideally suited to the survey and measurement of buildings and monuments.
Suitable photographs, usually stereoscopic, are taken on site, with a ‘control’ network established to determine the photographs’ scale and orientation. Photographs are taken using precision cameras, usually known as metric cameras, and full stereoscopic coverage of the building is produced. Control information may be either taped distances on the building façade, or the establishment of 3D coordinates of either target markers or identifiable points of detail.
The usual end-product of a photogrammetric survey is the production of either digital data or a line drawing. The data may be formatted for use in CAD systems, offering the advantage of flexibility. As the process requires photography, this may become the end-product itself, either archived as they are, or as a rectified mosaic composed of a number of scaled photographs joined together.
 Related articles on Designing Buildings Wiki
- Archaeology in the built environment.
- Archaeological officer.
- Architectural photography.
- Building archaeology and conservation.
- Building pathology.
- Building survey.
- Designated areas.
- Desk study.
- Digital mapping and cartography.
- Listed buildings.
- Recording old industrial sites.
- Restoring Charles Drake's concrete house.
- Scheduled monuments.
- The Archaeology Data Service.
 External resources
The IHBC’s latest Toolbox Guidance Note, on ‘Alterations to Listed Buildings’ has been issued following UK-wide consultation.
The ruins of Ousdale Burn Broch, north of Helmsdale in Caithness, had fallen into further disrepair over the past 130 years.
Europe’s largest air museum and Britain’s best-preserved Second World War airfield – has been included in Grade II* listing, even though technically too recent.
The College of Arts and Conservation has won the award for a for a project which provides or improves facilities for the community, including a £5.8M restoration of the College’s 126-year-old roof.
Completion of the restoration of Stowe House’s North Hall, largely funded by World Monuments Fund (WMF), came a step closer this summer with the installation of a statue of Mercury opposite the imposing Laocoön group installed last year.
The CREATIVE Conservation Fund helps the IHBC generate and distribute funds exclusively to deserving causes in built and historic environment conservation.
For years, there have been rumours whispered around Plymouth and Cornwall about so-called ‘nuclear tunnels’ that exist beneath the Tamar Valley.
Just under half of England’s busiest bridges are severely defected or damaged, but have remained open due to concerns about an influx of traffic should repairs be ordered, it has been revealed.
The issue focusses on the future of an historic city – Oxford – and includes an introduction by Layla Moran MP, Chair of the new APPG on Conservation, People and Places which has the IHBC as its Secretariat.
Opponents of the Stonehenge Tunnel have instructed lawyers to examine the legality of transport secretary Grant Shapps’ decision to give the scheme the green light.