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Thermography is a non-destructive testing technique used to evaluate the thermal performance of buildings, typically post-construction. However, establishing objective criteria for the interpretation of test results is not straightforward and the process can appear subjective. In building design, computer modelling may be used to analyse the thermal performance of construction details, including the expected distribution of surface temperatures at junctions and openings. The objective of this paper is to explore how the two techniques may be used together to support the identification and assessment of insulation defects in the construction of building façades. Firstly, a literature review identifies the main parameters relevant to modelling heat transfer through construction details and also the parameters that influence the assessment of surface temperatures by thermography. Combining the two techniques can support thermal image interpretation and the assessment of defect severity.Procedures to ensure a consistent approach between the two techniques are developed. Two case studies demonstrate the application of these procedures and illustrate the complementary use of modelling and thermography in a practical context. The approach discussed in the paper could help to verify the as-built energy performance of new buildings by linking design predictions of thermal performance with thermographic testing.

Purpose -The purpose of this paper is to discuss the methodology and results of using thermography for pre-retrofit (pre-R:T) and post-retrofit (post-R:T) surveys undertaken to qualitatively assess retrofitted external wall insulation (EWI) on pre-1919 existing dwellings with solid exterior walls. Design/methodology/approach -This study involved undertaking qualitative thermography surveys before and after installation of EWI at two mid-terrace dwellings in Swansea (UK). One dwelling was part of a whole-street approach and the other was an isolated installation. Findings -The two case studies have provided evidence of potential thermal bridges created as a result of an incomplete covering of EWI. Whilst overall heat loss appears to have been reduced, further evidence is required to establish the extent to which these thermal bridges reduce overall thermal performance.Research limitations/implications -Only two schemes undertaken in Swansea (UK) are represented in this study and are therefore not a reflection of EWI installations generally. Nevertheless, the study suggests more general concerns with the installation of EWI where a continuous covering of insulation cannot be achieved. Further research is required to assess the long-term implications of thermal bridges on the condition of the dwelling and the health of occupants. Originality/value -This paper has introduced and tested a pre-R:T and post-R:T methodology for assessing the thermal performance of deprived dwellings, which have had EWI retrofitted to solid exterior walls. By using the pre-R:T and post-R:T methodology the paper has demonstrated a visual method for illustrating problems in retrofitting EWI and highlighted improvements in thermal performance, which can be used by stakeholders involved in the maintenance and improvement of existing dwellings.

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