Although mould growth is usually associated with non-insulated houses, this study has shown that mould can also occur in well-insulated modern dwellings.
However, this is usually due to the combined effect of a few factors, most notably thermal bridging coupled with high moisture generation and/or insufficient ventilation. It is significant that thermal bridging is usually coupled with insufficient ventilation and that higher moisture generation is the most likely reason for mould contamination in the studied Milton Keynes houses.
Figure 9.9 Detail of mould growth by window frame (a) and IR image of the same area (b) indicating
thermal bridging in the same area
Table 9.1 Four dwellings with mould and the presence of factors for mould growth
Influencing Dwelling Dwelling Dwelling Dwelling
Parameters A B C D
Internal – Yes – –
temperature
Thermal Yes Yes Yes Yes
bridging
Moisture Yes Yes – Yes
generation
Building form – Yes – –
Ventilation Yes – – Yes
(a)
(b)
Although not all of the main observations required of a mould study were available from MK1, it has still been possible to develop a new methodology that includes the calculation and simulation of new parameters. This accounts for the deficiency of the building envelope in localized areas (i.e. the accurate modelling of fluctuating temperature conditions at the
‘deficient’ building surfaces), which significantly increases the likelihood of mould growth. This detailed case study analysis based on the monitored data in real dwellings, the physical surveys and the consequent modelling work has provided insight into identifying the parameters of most importance for mould growth in buildings. Alongside the results of other studies, it will help to inform guidelines for avoiding mould in well-insulated UK dwellings.
Discussion
More than just a case study, the MK0 study has been a highly invaluable sample to select for follow-up research.
This specific group of dwellings represented best practice in the UK domestic sector for the symbolically important year – in Kyoto Protocol terms – of 1990 and which were roughly a decade ahead of their time with respect to building regulation standards. As a result, they also provide an indication of what might be expected a decade from then, from dwellings of an equivalent standard. Our results found no evidence for any decline in the building fabric that has significantly affected building energy performance, though there was evidence of construction issues and thermal bridging in places, particularly around window frames – leading in some dwellings to mould growth. The general increase in gas use for space heating was accounted for by the increased floor space in the MK1 sample, but specifically in the top third of energy users in 1990. These tended to be larger dwellings and were where extensions had been added.
This high group also had a substantial rise in electricity usage, and by 2005 they used more energy than the other two groups combined. Although not representative of the UK dwelling stock, this work has pointed to the need for further research to help policy-makers refocus specifically on where energy is used and where change is occurring the most.
With the supplementary research, the MK1 study has also proven its usefulness for research on mould growth on UK dwellings. A methodology that combined modelling with detailed data of temperatures
and RH has clarified the role of four factors, including thermal bridging and moisture production. This information will contribute to the analysis and results for other studies and, ultimately, improve guidelines for avoiding mould. It is also the case that with some minor additions and improvements on the initial data collection methodology for MK1, it would have been possible to investigate mould growth with an even more sophisticated and informative analysis.
In summary, the MK0 and MK1 studies provide a useful illustration for some of the issues and possibilities of energy and environmental research in the domestic sector. We have outlined the various considerations that need to inform the planning process for the study, while ensuring that the primary research objectives are met and being aware of the potential that good research methods have in enabling supplementary work to add value to the original data set. We have also highlighted the importance of referring to existing standard methodologies of data collection and classification to maintain compatibility and permit the results to be set within an appropriate scientific context. By describing in some detail the range of options associated with even the basic objectives, such as monitoring temperature and RH, we have endeavoured to portray the numerous considerations to be addressed, from maximizing reliability and accuracy to minimizing costs and occupant disturbance. Complex or even chaotic it may be on a large scale, but worthwhile research in this field must cope with the unpredictable and messy world of people and buildings as they are, rather than just how we imagine things should be in a laboratory or computer simulation.
Acknowledgements
We would like to acknowledge the support provided by Les Shorrock at the Building Research Establishment (BRE), who provided access to the original 1990 data set from Milton Keynes Energy Park, and to the residents who participated in the follow-up study.
References
BRE (Building Research Establishment) (2005) The Government’s Standard Assessment Procedure for Energy Rating of Dwellings, 2005 edition, BRE, Watford, UK
BSI (2002) BS EN ISO 13788:2002: Hygrothermal Performance of Building Components and Building Elements, BSI, London
Burr, M. L., Matthews, I. P., Arthur, R. A., Watson, H. L., Gregory, C. J., Dunstan, F. D. J. and Palmer, S. R. (2007)
‘Effects on patients with asthma of eradicating visible mould: A randomised controlled trial’, Thorax, vol 62, pp766–771
Bush, R. K., Portnoy, J. M., Saxon, A., Terr, A. I. and Wood, R. W. (2006) ‘The medical effects of mould exposure’, Environmental and Occupational Respiratory Disorders, Journal of Allergy and Clinical Immunology, vol 117, no 2, February, pp 326–332
Denning, D. W., O’Driscoll, B. R., Hogaboam, C. M., Bowyer, P. and Niven, R. M. (2006) ‘The link between fungi and severe asthma: Summary of the evidence’, European Respiratory Journal, vol 27, no 3, pp615–626 DETR (Department of Environment, Transport and the
Regions) (1991) English House Condition Survey 1991 Energy Report, DETR, London
DETR (1996) English House Condition Survey 1996 Energy Report, DETR, London
DTI (Department of Trade and Industry) (2007) Meeting the Energy Challenge: A White Paper on Energy, DTI, Government Stationery Office, London
Edwards, J. (1990) ‘Low energy dwellings in the Milton Keynes Energy Park’, Energy Management, vol 26, pp32–33 Fowler, F. J. (2008) Survey Research Methods, fourth edition,
Sage Publications, Thousand Oaks, CA
Hong, S. H., Oreszczyn, T., Ridley, I. and the Warm Front Team (2006) ‘The impact of energy efficient refurbishment on the space heating fuel consumption in English dwellings’, Energy and Buildings, vol 38, pp1171–1181 Janson, C., Anto, J., Burney, P., Chinn, S., de Marco, R.,
Heinrich, J., Jarvis, D., Kuenzli, N., Leynaert, B., Luczynska, C., Neukirch, F., Svanes, C., Sunyer, J. and Wjst, M. (2001) ‘The European Community Respiratory Health Survey: What are the main results so far?’ European Respiratory Journal, vol 18, pp598–611
Leaman, A. (2008) ‘Building performance: Research methods’
Monitoring: Proving Carbon Reductions and Informing the Path to a Low Carbon Future, Good Homes Alliance
Workshop April 2008, London, www.goodhomes.
org.uk/library_files/43, accessed May 2008
Mazur, L. J., Kim, J. and the Committee on Environmental Health (2006), ‘Spectrum of non-infectious health effects from moulds’, Journal of the Academy of Paediatrics, vol 118, pp1909–1926
ODPM (Office of the Deputy Prime Minister) (2003) English House Condition Survey 2001, ODPM, London ODPM (2006a) The Building Regulations, Approved
Document F1 – Means of Ventilation: 2006, OPDM, NBS, London, UK
ODPM (2006b) The Building Regulations, Approved Document L1a – Conservation of Fuel and Power in New Dwellings: 2006, OPDM, NBS, London, UK
ONS (Office of National Statistics) (2004) Harmonised Concepts and Questions for Social Data Sources Primary Standards, ONS, www.statistics.gov.uk/about/data/
harmonisation, May 2008
Oreszczyn, T. (1993), ‘The energy duality of conservatory use’, in Proceedings of the 3rd European Conference of Architecture: Solar Energy in Architecture and Planning, Florence, Italy, pp522–525
RSHA (Regional Strategic Housing Authority) (2001) Northern Ireland House Condition Survey 2001 Final Report, RSHA, UK
Sanders, C. H. (1989) ‘Dampness data in the 1986 English House Condition Survey’, International Energy Agency – Annex XIV: Report UK-T7-35/1989, Building Research Establishment Scottish Laboratory, East Kilbride, Glasgow, Scotland
Sanders, C. H. and Cornish, J. P. (1982a) ‘Dampness: One week’s complaints in five local authorities in England and Wales’, Building Research Establishment Report, HMSO, London
Sanders, C. H. and Cornish, J. P. (1982b) ‘Dampness complaints’, Building Research Establishment News, vol 58, pp2–3
Summerfield, A. J., Lowe, R. J., Bruhns, H. R., Caeiro, J. A., Steadman, J. P. and Oreszczyn, T. (2007) ‘Milton Keynes Energy Park revisited: Changes in internal temperatures and energy usage’, Energy and Buildings, vol 39, pp783–791
Introduction
The aim of this case study is to describe in detail the development of the Domestic Energy and Carbon Dioxide Model (DECARB), a physically based model of the UK housing stock that is capable of forecasting the energy use and CO2emissions attributable to this sector under a range of possible futures. This model has been used to develop a number of illustrative scenarios for the UK housing stock in order to explore the technical feasibility of achieving CO2 emission reductions in excess of 60 per cent within this sector by the middle of this century. Reductions of this order are likely to be required across industrialized countries in order to stabilize the atmospheric CO2 concentration and mitigate the effects of climate change.