Climate change and the greening of masonry: implications for built heritage and new build
Lead Research Organisation:
University of Oxford
Department Name: Geography - SoGE
Abstract
Abstracts are not currently available in GtR for all funded research. This is normally because the abstract was not required at the time of proposal submission, but may be because it included sensitive information such as personal details.
Publications
McCabe S
(2011)
The 'Greening' of Natural Stone Buildings:Quartz Sandstone Performance as a Secondary Indicator of Climate Change in the British Isles?
in Atmospheric and Climate Sciences
Smith B
(2010)
A commentary on climate change, stone decay dynamics and the 'greening' of natural stone buildings: new perspectives on 'deep wetting'
in Environmental Earth Sciences
Cutler N
(2014)
The spatial organization and microbial community structure of an epilithic biofilm
in FEMS Microbiology Ecology
Cutler N
(2010)
Eukaryotic Microorganisms and Stone Biodeterioration
in Geomicrobiology Journal
Viles H
(2012)
Global environmental change and the biology of heritage structures
in Global Change Biology
Cutler N
(2013)
The characterisation of eukaryotic microbial communities on sandstone buildings in Belfast, UK, using TRFLP and 454 pyrosequencing
in International Biodeterioration & Biodegradation
Cutler NA
(2012)
Non-destructive sampling of rock-dwelling microbial communities using sterile adhesive tape.
in Journal of microbiological methods
Smith, B J
(2011)
Climate change and the investigation of complex moisture regimes in heritage stone: preliminary observations on possible strategies.
in Materials Evaluation
Cutler NA
(2013)
Algal 'greening' and the conservation of stone heritage structures.
in The Science of the total environment
| Description | Algal greening and moisture regimes in sandstone walls have been found to be complex and dynamic. Using a combination of field measurements on historic sandstone walls in Belfast, monitoring of test walls at Derrygonnelly and a series of small-scale field and laboratory experiments we have investigated the nature, dynamics and impacts of algal greening and deep-seated wetness on the deterioration of a range of building sandstones. Using innovative 2D resistivity surveys of historic sandstone walls in Belfast we found very patchy coverage of algal greening, and no evidence that such greening is correlated with, or causes, wetter conditions in the immediate sub-surface zone. State-of-the-art molecular methods have been used to characterise the biological communities within the green areas - finding higher diversity than expected, with a relatively homogeneous group of algae and considerable fungal diversity across different walls and sample areas. Slow development of algal greening on the Derrygonnelly test walls precluded more detailed observations within the timeframe of the project, but the developing communities can be studied in future. Field experiments using smaller blocks and architectural elements (balusters) illustrated the importance of aspect and slope angle to the rate of greening. Laboratory experiments under highly controlled conditions showed how algal greening is 'fine-tuned' to the amount of surface moisture present - both too much and too little moisture retards growth. 2D resistivity surveys of Belfast walls also revealed several instances of deep-seated wetting, with areas 20-30cm inside the stone surface appearing highly wet. Patchy moisture regimes were the norm. Monitoring of wetting and drying on the Derrygonnelly test wall site further illustrated the importance of aspect, and the non-linear progress of wetting. Only after long wet periods did the moisture front penetrate far (> 20cm) into the walls, predominantly on the exposed, SW-facing side, with very slow drying. Statistical downscaling of GCM data shows that such wet periods are projected to increase in the coming century, though the magnitude of this increase varies across NW UK. Laboratory experiments, carried out over 2 month periods, show the importance of diffusion of ions under saturated conditions and the complications introduced when mixed salt solutions are used. Very high pHs were found in some experiments (> 10), indicating that mobilisation of silica could be an important weathering process under conditions of deep-seated wetness. In sum, our multidisciplinary, multi-method study has demonstrated the complexity of responses of sandstone facades (historic and new build) to prolonged heavy rainfall. Algal greening has not been found to directly influence surface deterioration, but may act as a signal of altered moisture regimes which in turn have the potential to induce deep-seated chemical transformations likely to make sandstone more vulnerable to deterioration (because of mobilisation and patchy re-precipitation of silica). Our research has involved the development of many innovative techniques for monitoring moisture in walls and characterising algal communities and their impacts (several of which are available to view on the internet as a result of additional EPSRC Pathways to Impact funding). There are several practical implications of our research, which have been discussed with our external advisory panel and further disseminated through two linked EPSRC-funded Knowledge Transfer Scheme activities. Firstly, algal greening has been shown to be less directly damaging than commonly thought, and KTS work with Historic Scotland has included this information in improved INFORM guidance notes for practitioners. Secondly, KTS work with S McConnell & Sons Ltd on surface treatments has shown some to be effective on porous sandstones, delaying water uptake, and potentially reducing moisture-driven decay. |
| Exploitation Route | Both algal greening and deep seated wetting can cause problems for conservators and architects managing sandstone buildings. Our findings can help their decision-making, by providing advice based on our integrated field and laboratory programme. Furthermore, our findings can be taken forward by those wishing to develop optimised techniques for measuring moisture in walls and determining its impacts on deterioration and algal colonisation. |
| Sectors | Construction,Environment |
| URL | http://www.qub.ac.uk/schools/ClimateChangeandthegreeningofmasonryimplicationsforbuiltheritageandnewbuild/Project/ |
| Description | Our research findings have been used by a KE project with Historic Scotland to develop updated briefing on greening and deterioration; and as the basis of a workshop on non-destructive techniques for diagnosing moisture and other problems in masonry walls. Furthermore, our findings have led to longer term collaborations with Consarc Design and Historic Scotland, to provide better toolkits for monitoring moisture dynamics in masonry walls. |
| First Year Of Impact | 2012 |
| Sector | Construction,Culture, Heritage, Museums and Collections |
| Impact Types | Policy & public services |
| Description | Consarc and Stone Conservation Services |
| Organisation | Consarc Design Group |
| Country | United Kingdom |
| Sector | Private |
| PI Contribution | Research on the implications of climate change for algal greening and deep wetting of stone masonry |
| Collaborator Contribution | Contributing design and conservation advice, including designing the test walls; providing access to database of stone deterioration acorss northern Ireland; advice on how to make our findings relevant to practitioners |
| Impact | Project workshop April 2012 and associated online resources. Collaboration is multi-disciplinary, involving architects, engineers, geologists, geomorphologists, climatologists and ecologists. |
| Start Year | 2009 |
| Description | Consarc and Stone Conservation Services |
| Organisation | Stone Conservation Services |
| Country | United States |
| Sector | Private |
| PI Contribution | Research on the implications of climate change for algal greening and deep wetting of stone masonry |
| Collaborator Contribution | Contributing design and conservation advice, including designing the test walls; providing access to database of stone deterioration acorss northern Ireland; advice on how to make our findings relevant to practitioners |
| Impact | Project workshop April 2012 and associated online resources. Collaboration is multi-disciplinary, involving architects, engineers, geologists, geomorphologists, climatologists and ecologists. |
| Start Year | 2009 |