Key stakeholders’ perspectives towards UK new-build housing defects

Purpose: Research on housing defects has limited its enquiry to the classifications of defects, potential impact of defects, and their detection and remediation during construction and the builder’s liability period, without considering the warranty period. This paper aims to better understand which impacts of defects are perceived as important by the key stakeholders involved in their detection and remediation over the construction, builder’s liability and insurer’s warranty periods. Design/methodology/approach: The questionnaire survey approach was used. The questionnaire distribution list was drawn from the UK’s largest warranty provider and approved inspector’s records. The questionnaire was distributed to 2003 people, receiving 292 responses, a response rate of 15%. Findings: This research challenges the assertion that the house building industry (i.e. house builders, building inspectors and warranty providers) is predominantly cost focused and finds that the potential impact of defects on home occupants are their primary concern. In contrast, the home occupants’ appear solely focused on the disruption defects caused on their daily lives and perceive a lack customer focus in the house building industry. Originality/value: This study provides empirical evidence of the contrasting view of the house building industry and home occupants with respect to the prioritisation of the impacts of defects. Further, this research offers house builders an alternative approach to determine which defects should be targeted for reduction purposes which may lead to improved levels of customer satisfaction

Resilience, redundancy and low-carbon living: co-producing individual and community learning

There is an acknowledged need for buildings and communities to be more resilient in the face of unpredictable effects of climate change, economic crises and energy supplies. The notion and social practices involving redundancy (the ability to switch between numerous available choices beyond optimal design) are explored as an aspect of resilience theory. Practice and Social Learning theories are used as a lens through which to explore the available redundancy in housing and home environments to help prevent performance failure through unexpected circumstances or in response to varying user needs. Findings from an in depth UK housing case study show how redundancy is linked with the capacity to share resources and to learn both individually and collectively as a community. Such learning in relation to resilient low-carbon living is shown to be co-produced effectively through participatory action research. The benefits of introducing extra redundancy in housing design and community development to accommodate varied user’s understanding and preferences are discussed in relation to future proofing, value and scalar issues. Recommendations include better understanding of the design, time and monetary contribution needed to implement social or technical redundancy. These costs should be evaluated in context of savings made through greater resilience achieved

Managing the extent of tree removal from railway earthwork slopes

Trees cover the slopes of many earthworks (embankments and cuttings) supporting the UK’s rail network. Trees provide ecological and slope stability benefits to earthwork slopes but they can also cause seasonal shrinking and swelling of the soil. Seasonal shrink-swell movement in earthworks can affect the level and alignment of the track, causing delays for rail passengers and a substantial cost for infrastructure owners. Guidance is required to identify and manage the removal of problematic trees, while avoiding full tree clearance on earthworks slopes.A study was undertaken on behalf of London Underground Ltd (LUL) to assess whether the National House Building Council (NHBC) guidance, considering tree species and the ratio of the distance of the tree from the track, D, to the mature tree height H, might be applicable to trees located on railway earthwork slopes. Excessive seasonal track movement was shown to correlate with the presence of high water demand (HWD) tree species located within a certain D/H ratio of the track, but not other tree species.Soil heave was measured on the slope of an instrumented railway embankment following removal of trees from the embankment slope. The rate and magnitude of soil heave was estimated from five years of pore water pressure data, using a one dimensional settlement/heave calculation based on a linear swelling index. It was found that while the removal of HWD trees reduced seasonal shrink-swell movement, soil heave and upward track movement continued for at least 4 years after tree felling

Pile heat exchangers: thermal behaviour and interactions

Thermal piles – that is structural foundation piles also used as heat exchangers as part of a ground energy system – are increasingly being adopted for their contribution to more sustainable energy strategies for new buildings. Despite over a quarter of a century having passed since the installation of the first thermal piles in northern Europe, uncertainties regarding their behaviour remain. This paper identifies the key factors which influence the heat transfer and thermal–mechanical interactions of such piles. In terms of heat output, pile aspect ratio is identified as an important parameter controlling the overall thermal performance. Temperature changes in the concrete and surrounding ground during thermal pile operation will lead to additional concrete stresses and displacements within the pile–soil system. Consequently designers must ensure that temperatures remain within acceptable limits, while the pile geotechnical analysis should demonstrate that any adverse thermal stresses are within design safety factors and that any additional displacements do not affect the serviceability of the structur

Optimising construction with self-compacting concrete

Winner of the 2018 ICE Publishing Awards (Thomas Howard Medal) for the best paper of the year in the Construction Materials journal. Permission is granted by ICE Publishing to print one copy for personal use. Any other use of these PDF files is subject to reprint fees.Self-compacting concrete or self-consolidating concrete (as it is known in North America) (SCC) is used on the basis of its unique properties of flowability, passability and resistance to segregation. It requires no external energy to achieve full compaction, so is advantageous on site, but there is evidence that its higher cost is a significant barrier to greater adoption. The research entailed work measurement of 14 UK single-family home residential projects (eliciting data on construction time and labour productivity) and cost modelling of three slab scenarios (exploring the relationship between material and labour costs). The study found SCC was placed up to 73% faster than conventional concrete and, when labour and material costs are included, the supplier is able to price SCC to closely match conventional concrete, hence making SCC more viable for the contractor. This relationship between as-built costs for SCC and conventional concrete is clarified by developing Pmax, providing a new mechanism for understanding project profitability and viability of SCC

An evolutionary innovation perspective on the selection of low and zero carbon technologies in new housing

The Code for Sustainable Homes (the Code) will require new homes in the United Kingdom to be ‘zero carbon’ from 2016. Drawing upon an evolutionary innovation perspective, this paper contributes to a gap in the literature by investigating which low and zero carbon technologies are actually being used by house builders, rather than the prevailing emphasis on the potentiality of these technologies. Using the results from a questionnaire three empirical contributions are made. First, house builders are selecting a narrow range of technologies. Second, these choices are made to minimise the disruption to their standard design and production templates (SDPTs). Finally, the coalescence around a small group of technologies is expected to intensify with solar-based technologies predicted to become more important. This paper challenges the dominant technical rationality in the literature that technical efficiency and cost benefits are the primary drivers for technology selection. These drivers play an important role but one which is mediated by the logic of maintaining the SDPTs of the house builders. This emphasises the need for construction diffusion of innovation theory to be problematized and developed within the context of business and market regimes constrained and reproduced by resilient technological trajectories