MCRG Research Areas

This page contains abstracts on areas which have been or are being researched by the Masonry Conservation Research Group.
Further information and, in some cases, summaries of results are available.

Stonecleaning: Effects of stonecleaning methods on Scottish sandstones

Uncontrolled stonecleaning in the past has caused severe damage to a number sandstone buildings in Scotland. Damage occurs through a lack of understanding of both the immediate and long-term effects that stonecleaning treatments can have on stone. This research investigated the effects of physical and chemical stonecleaning methods on building sandstones and determined which tests should be performed on the sandstone prior to cleaning to choose a stonecleaning method which will not result in excessive damage to the stone.
For more information follow this link
Last updated March 2003

Following this research programme, in 1994 the MCRG and Historic Scotland published "Stonecleaning: A Guide for Practitioners". This book summarised the research results in a form which will be useful to stonecleaning practitioners.

Aesthetics of cleaning of building sandstones

One of the aims of researchers in the field of experimental aesthetics in relation to facade soiling and cleaning has been to develop a model which predicts the change in ascribed aesthetic value of building facades as they progress through cycles of soiling and cleaning.
For more information follow this link
or contact Dr Chris Andrew at c.andrew@rgu.ac.uk
Last updated 13 February 2001

Stonecleaning: Effects of stonecleaning methods on Scottish granites

Granites are used as building stones in and around Aberdeen and in south west Scotland. This research continued from that done with sandstones, however, due to their much lower permeability, the response of granites with respect to cleaning can be very different to the behaviour of sandstones. This research determined the effects of physical and chemical stonecleaning methods on building granites and which tests should be performed on the granite prior to cleaning to choose a stonecleaning method which will not result in excessive damage to the stone.
For more information follow this link
See also details of a Technical Advice Note on stonecleaning of granite.

Value assessment of stonecleaning

The cleaning of stone facades can affect the built environment in a number of ways. In addition to changes in the physical state of the stone, the process might also influence:

• the visual perception of the built environment
• associated property market values
• related industries e.g. stone supply, stone repair
• wider environmental values

This research has investigated these areas in some depth, providing an insight into how they might relate to one another.
For more information follow this link

Stonecleaning and stone decay

This research project aimed to gather objective and statistically valid data to determine the negative, or indeed positive, effect that the cleaning of sandstone has had on the incidence of stone decay affecting a building facade, when compared to stonework which has not been cleaned. The ultimate aim of the research was to provide an indication of the cost of stone repair as a consequence of cleaning. The research report builds upon and develops an undergraduate honours degree project in the Scott Sutherland School undertaken by Marion Roberts.
For more information follow this link

Long term consequences of stonecleaning

Over the past 20-35 years cleaning of stone facades of buildings has been a significant activity, both in terms of financial outlay and the effect on the built heritage of our cities. Removal of the soiling layer has been perceived by the general public and building owners as a "good thing" because of the simplistic notion that a clean, bright facade reflects well on the urban environment in general and on the image of the building occupier in particular. It is now known that much of this past stonecleaning intervention has been carried out in ignorance of the effects and consequences that this work has had on the stone. The need for objective and quantifiable evidence on the impact that stonecleaning has on the incidence of stone decay and stone replacement is now urgently required if proper guidance is to be provided, to both practitioners and the stone industry on the scale of the problem.
For more information follow this link
Last updated 12 February 2001

Algal growth and effects and efficacy of biocides on building sandstones

Extensive green algal growths on sandstone buildings may be considered disfiguring. Biocides are sometimes used to control algal growth on building stones. The effectiveness and the effective lifespans of these biocides varies depending on the composition of the biocide and the characteristics of the sandstone.
For more information follow this link
See also details of a Technical Advice Note on the control and treatment of biological growths.

Factors affecting growth of algae on sandstones after stonecleaning

It has been reported anecdotally that following stonecleaning algal growth or re-growth on buildings occurred very rapidly and in greater abundance than was present prior to stonecleaning. This research investigated how physical (e.g. grit blasting) and chemical stonecleaning methods can influence the rate of algal growth on sandstones.
For more information follow this link
Last updated 29 May 1998

Biodeterioration by algae at Hermitage Castle, Scotland

For more information contact Dr. Rachael Wakefield at r.wakefield@rgu.ac.uk

Salt decay in building sandstones

Follow the link below to see the salt weathering connection section-page, I hope you find it so interesting you cannot leave it until the very end, if not, please send me your comments anyway. I am doing my PhD within the Masonry Conservation Research Group in Aberdeen. My project is looking at the mechanisms of salt weathering decay in sandstone buildings in Scotland. I would be very keen in establishing contact with research partners or groups working in sandstone weathering all around Europe, so any of you reading this page please take note!!
For more information follow this link

Consolidants and water repellents on sandstones

Water repellents and consolidants are used to minimise the rate of stone decay or biological colonisation and to strengthen decayed stone where there has been a failure of the natural stone cohesion. In the past 20 years many materials have been used with varying degrees of success and no single method has been found to be successful on all stone types. The aim of this research programme was to examine the effects of various consolidants and water repellents on Scottish building sandstones.
For more information follow this link
Last updated 15 March 1999

Scottish Market Crosses: The Development of a Risk Assessment Model

This research is concerned with analysing the erosion and conservation of Scottish market crosses and recommending management strategies based upon this. A mapping methodology has been developed to record in detail the condition of the stone surfaces for these monuments. The data values collected during fieldwork and archival research were analysed and a risk assessment model developed for Scottish market crosses.
For more information follow this link, or contact Lindsey Thomson at m.young@rgu.ac.uk
Last updated 14 February 2001

Impact of oil pollution from Braer Wreck on Historic Scotland Monuments in Shetland

Follow this link for more information, or contact Dr Keith Nicholson at k.nicholson@rgu.ac.uk

Access to the built heritage

There are special problems associated with the provision of access for visitors with disabilities at historic buildings and ancient monuments that are open to the public. A balance must be struck between accessibility and the preservation of the character of the site. Accessibility should not threaten or destroy features and materials that convey the property's significance. In order to achieve the greatest possible level of accessibility, imaginative solutions must be sought which incorporate an integrated review of access and which do not diminish the value of the monument. In the end, however, physical access may not always be possible. However, in the assessment or management of a building or site in respect of access, it is important to recognise that disabled people have a right to expect, where possible, dignified and easy access to and within historic buildings and sites.
For more information follow this link