This year the annual ISG Committee Away Day was held at the brand new Historic Environment Scotland facility, The Engine Shed in Stirling, a centre for education and conservation of the built environment.
In his introduction, Brian Wilkinson the Activities and Events Manager, explained that there are around half a million traditional buildings in Scotland, i.e. those that pre-date 1919. Changes in building construction after the First World War led to a gradual loss of historic practice, a skills shortage and inevitably the use of inappropriate materials resulting in preventable damage to our built heritage.
One of the prime functions of this new centre is to redress the balance by providing the skills and material knowledge to care for our traditional built heritage and to disseminate this through the building industry and the wider population: from an Advanced Professional Diploma in Technical Building Conservation [awarded by the University of Stirling], individual modules which can be utilised for CPD training to visits from primary school groups and free publications.
A traditional building itself, the Engine Shed was built somewhere between 1890 and 1910 in the former 40 acre military re-distribution complex; the precise date of construction is unknown due to the absence of military information on contemporary maps.When the military left the site in the 1990’s the building fell into disrepair and stood empty until acquired by HES in the early 2000’s. On the completion of a ten-year project, funded by HLF, it was officially opened on 3rd July 2017. It embodies the principles that HES are duty bound to uphold in that it is sustainable, environmentally sound, utilises only biodegradable, recycled and recyclable materials, many of which are sourced locally: Glulam beams, sheep wool insulation, ground source heat pumps, clay mortar and zinc cladding to name a few.
On our tour of the facilities, conservation scientist Callum Graham highlighted some of the non- destructive analytical techniques employed by HES and their multiple applications. An interesting example was the use of the portable XRF machine to examine fragments of the Glasgow School of Art library lights to identify the precise nature of the materials used by Macintosh in their construction…the presence of specific concentrations of copper and zinc indicated a particular grade of brass and a lead and tin solder. It was also interesting to discover that this technique can be used to determine the age of glass e.g.- the presence of strontium indicates a specific period when kelp was used in glassmaking.
Another valuable portable examination technique was the handheld thermal imaging camera. The camera detects IR radiation and is used to locate issues with historic buildings such as heat loss and water ingress.
Callum explained the use of microwave moisture sensors to measure the moisture content within the walls of buildings and the necessity of accurate stone matching in building conservation. Petrographic microscopy is an essential technique in the identification of grain structure and mineralogy in stone as an incompatible stone repair within a building can accellerate the decay of original, historic material.
The work of the Digital Documentation Team was introduced by surveyor and spatial analyst, James Hepher and digital documentation intern, Marta Pilarska. The team use photographic, photogrammetric and 3D laser scanning surveys to record the contours and topography of both the monumental e.g.- castles and coastlines to the miniature e.g. tooled leather book covers, coins and wax seals.
Different techniques are used to serve many purposes, for example: 3D laser scanning of landscapes allows the creation of a baseline record from which to map erosion, compare future data sets, to inform on the effects of interventions and to plan new conservation approaches. For smaller scale objects, digital photogrammetry utilises stereo imaging software to transform 2D images into 3D information which can then be used in the 3D printer to create scalable facsimiles, which in turn have multiple applications.
3D prints -some reduced in scale
RTI [Reflectance Transformation Imaging] is, on the face of it, an affordable and accessible technique which creates a synthesised 2D image capturing a high degree of detail of the surface contours of an object. Marta explained that using a stationary, securely mounted SLR camera, a good, portable light source and free software from ‘Cultural Heritage Imaging’ it is possible to record astonishing topographical detail that would otherwise not be immediately visible.
The Gigamacro photogrammetry imaging system
Icon Scotland Group Committee would like to thank all of the HES staff at The Engine Shed for a very informative and enjoyable day.