Improving the evaluation of conservation treatments for deteriorating sandstone in built heritage (Spotlight on SEAHA)

Our third ‘Spotlight on SEAHA’ guest post comes from Richard Grove who outlines his research into finding out whether sandstone treatments are providing the protection that was intended.

This research sets out to create practical guidance for assessing the effectiveness of historic stonework treatments. Many sandstone structures, artefacts, and archaeological sites have been treated with some sort of consolidating coating where the surface or structure has been eroded by time, weather or the action of humans or animals. As yet, there is no standard procedure for assessment, meaning there is no way of telling if the treatments currently used are helping or damaging the thing they are meant to protect.

The guidance resulting from this project can be adopted by both academic and commercial conservators, as it will be applicable to a wide range of treatments across the world, and not just a single type. It will change the way all who work on sandstone heritage understand how the treatments they use interact with the stone, by using heritage science to answer complex questions on historic materials.

Image of Oxford's Rock Breakdown Laboratory
Part of Oxford’s Rock Breakdown Laboratory where samples will be treated (image (c) Richard Grove)

The project will combine a range of laboratory based tests combined with simulated and real world case studies. There will be samples taken of sandstone types commonly used in conservation works, and found on historic buildings around the world. Samples will be weathered in our laboratory, to emulate the advanced decay of some of the most iconic sites globally. These samples will then be treated with a range of commercially available solutions; after which they will be subjected to some further accelerated weathering.

Image of stone samples undergoing internal testing
Stone samples undergoing internal testing (image (c) Richard Grove)

The samples will be subject to a range of tests throughout this process, from their ability to absorb and let out moisture (see image of the Karsten Tube Experiment below), to their strength under a range of forces such as compression and twisting. These tests will provide us with a range of measurements from which we can assess the performance of all available treatments in a range of situations, and help us design a model for testing on site without the need to take samples from the vulnerable sites themselves.

Image of stone sample undergoing Karsten Tube testing
Karsten Tube Testing, measuring the moisture uptake of the stone samples (image (c) Richard Grove)

This research is intended to benefit anyone who has an involvement in the maintenance and repair of sandstone in a range of settings, from archaeological sites such as Palaeolithic cave sites in the Near East, to modern municipal buildings in the UK. The range of situations where sandstone is employed is vast, and everyone involved in its maintenance or care will be able to benefit from the findings of this research.

Watch this space! Keep an eye on the SEAHA website and for information on the project as it develops.

The 3rd International Conference on Science and Engineering in Arts, Heritage and Archaeology (SEAHA) will take place on 19-20 June 2017 at the University of Brighton. Click here to view the programme of themed sessions and flash presentations, and here to register.

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