Alternative, more sustainable, wall construction techniques than brick and block, for new housing in England and Wales

There is a need to reduce the emissions of the country as a whole, to limit the risk of climate change due to Global warming and to meet targets set by the Kyoto agreement and the Climate Change Act. The large number of houses constructed annually in England and Wales have an important role to play in this. By reducing emissions, resulting from both the manufacture of construction materials and the energy used by house occupants, housing can help achieve the necessary emissions reductions. Alternative construction methods can contribute to this, either by having a lower embodied energy or by demonstrating good thermal properties to limit heat loss and hence operational energy. However, it is essential that both the construction industry and the public accept the alternative construction methods for them to be economically viable. In addition, there should be no loss of performance as a result of using alternative construction methods. Six methods of construction were studied in depth, including generating embodied and operational energy requirements and identifying their performance in terms of airtightness, wall thickness, and fire resistance. Public and industry acceptability were examined by use of questionnaires. A comparison of the data collected showed that identifying the best, or optimal, option visually is a challenging task as no single method of construction is best in all areas. A methodology was created to aid the selection of a wall construction method. The methodology is capable of examining multiple variables, in this work it is demonstrated with construction method and front building dimension. To identify the optimal method, optimisation by genetic algorithms is used. Use of the methodology was demonstrated with a case study based on the most frequently constructed housing type for England and Wales. The importance of weighting was demonstrated with the use of weightings based on concerns held by different parties. It was found that minimising the external wall area gives the optimal solution as less material is needed and there is less opportunity for heat loss. For the situation examined in the case study, Structural Insulated Panels (SIPs) were identified as having the potential to reduce the environmental impact of housing construction in England and Wales without impacting saleability or performance.