No-fines concrete in the UK social housing stock: 50 years on James Sommerville, Nigel Craig and Antoinette Charles Glasgow Caledonian University, Glasgow, UK Abstract Purpose – No-fines concrete (NFC) is an open textured cellular concrete obtained by eliminating either fines or sand from the normal concrete mix. Research in the 1950s showed this material to be capable of energy and cement savings and worthy of being seen as a material that would revolutionise the way affordable homes could be built. In today’s context, it may be argued that homes built using this material suffer from fuel poverty as a result of their thermal performance characteristics. This paper seeks to discuss the performance characteristics of NFC in social housing by identifying the nature of the material and the influence of pore structure on heat loss through the fabric of the building. Design/methodology/approach – Exploratory work was carried out to determine the build and performance characteristics of NFC as used in a range of social housing units. The work includes both laboratory tests and site investigations to identify the physical, thermal, visual and quality characteristics of NFC in cores taken from existing housing units in Irvine, Scotland and units cast in the lab. Findings – The findings from the tests are used to discuss the actual characteristics of NFC and highlight the nature of pores in NFC and, their influence on heat loss through the external fabric. Practical implications – Identifying the nature of pores in NFC helps provide approaches towards optimising solutions aimed at improving the thermal performance of the building. Originality/value – This paper is the first to discuss the on-site build and performance characteristics of NFC and the nature and influence of pores on the thermal performance of NFC. Keywords No-fines concrete, Social housing, Performance characteristics, Energy loss, Fuel poverty, Energy management, Cement and concrete technology Paper type Research paper Use of no-fines concrete (no-fines) (NFC) construction in social housing As everyone may be aware, if you trap air pockets in a material then they tend to act as insulation. NFC is a non-traditional form of construction adopted in the UK prior to 1980, to build a variety of house types, i.e. detached, terraced, semi-detached and multiple storey. Moss (1979) described the structure of NFC as an open textured cellular concrete. This cellular structure is formed as a result of the absence of fine aggregate and lack of compaction (Concrete Construction, 1961; Williams and Ward, 1991). NFC is cast in situ by pouring cement and coarse aggregate slurry into steel forms. In theory, the absence of fines/sand in the structure, would lead to the formation of voids which would act as insulation and prevent the flow of air, water and heat through the structures: walls could be cast 7.5 metres high and 18 metres long, speeding up the overall construction process. Concrete Construction (1961) noted the only compaction required in NFC construction is a light rodding to ensure the form is filled without bridges around obstructions; the storey height of the formwork playing an important part in providing sufficient compaction, by gravity alone. The number of NFC units built in the UK can be estimated at around 300,000, over a period of 30 years from the 1950s to the 1980s (Ross, 2002). After communicating with the 32 Scottish Local Authorities; data from them suggest that there are circa 33,000 NFC homes in Scotland whose external walls (and internals) were constructed from NFC (see Figure 1). Since no standard approach was adopted in the casting of The current issue and full text archive of this journal is available at www.emeraldinsight.com/0263-080X.htm Structural Survey Vol. 29 No. 4, 2011 pp. 294-302 r Emerald Group Publishing Limited 0263-080X DOI 10.1108/02630801111162369 294 SS 29,4