The thermal conductivity and diffusivity of un-fired clay bricks, a straw clay mixture and straw bales have been measured using a thermal probe technique, with an iterative method for data analysis. The steady-state air-to-air thermal transmittance, or Uvalue, and the time-dependent thermal properties of some proposed sustainable earth wall constructions are presented. Sustainable cavity walls of un-fired clay bricks with paper, straw or wool cavity insulation have thermal transmittances less than 0.35 W/m 2 K, and therefore meet the current United Kingdom Building Regulations. A review of possible methods for thermally up-grading existing earth walls, by adding an internal insulated timber frame construction, again demonstrates possible compliance with the current UK thermal regulations.

Thermography is becoming more widely used amongst construction professionals for energy related defect detection in buildings. Until quite recently, most of the research and practical use of building thermography has centred on employing a building walk-around or walkthrough methodology to detect sources of unacceptable energy use. However, thermographers are now creating new building thermography methodologies that seek to address some of the known limitations, such as camera spatial resolution, transient climatic conditions and differences in material properties. Often such limitations are misunderstood and sometimes ignored. This study presents a review of the existing literature, covering both well-established and emerging building thermography methodologies. By critically appraising techniques and observing methodology applications for specific energy related defects, a much clearer picture has been formed that will help thermographic researchers and thermographers to decide upon the best methodology for performing building thermography investigations and for the invention of new approaches. Whilst this paper shows that many of the different passive building thermography methodologies seek to address particular building issues such as defects and energy use, it has also demonstrated a lack of correlation between the different methodology types, where one methodology is often chosen over another for a particular reason, rather than making use of several methodologies to better understand building performance. Therefore this paper has identified the potential for using several passive building thermography methodologies together in a phased approach to building surveying using thermography. For example, a less costly and faster survey could be conducted to quickly identify certain defects before enabling more time consuming and expensive surveys to hone in on these with greater detail and spatial resolution if deemed necessary.

The application of Microsoft Excel Solver routines to analyze data from a thermal probe placed in a number of samples is described. The successful application of the Solver routine to the thermal probe temperature time data requires the selection of an appropriate time interval. The various critical times are discussed and a method is proposed for selecting the appropriate Solver routine and the time interval over which the experimental data must be analyzed. Values of the sample thermal conductivity, the thermal diffusivity and the probe to sample conductance are reported for a stainless steel probe in unused mineral oil, and paraffin wax and for a copper probe in Magna904 and PTFE. The results for a commercial probe in agar agree with accepted data for water and the results for a claystraw mixture demonstrates the method applied to a good insulator.140 words

This paper examines the use and accuracy of a moisture probe used in the walls of a straw-bale building. The performance of the moisture probe is assessed against laboratory based measurements. The measurements from a number of moisture probes placed in the walls of a case study straw-bale building over a two-year period are presented. The moisture content measurements from the building are discussed in the light of laboratory findings and the condition of the straw in the lower part of the most exposed wall. Potential influences upon the readings obtained from the moisture probes along with possible alternative assessment methods are discussed.

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a b s t r a c tMany buildings suffer from defects in the building envelope, such as missing insulation, thermal bridging, cracks and moisture problems. Thermography is one technology that can help to identify such defects. However, there are different approaches towards assessing the building envelope. Pass-by thermography is an emerging method, which is used to capture single thermal images of external building elevations. Compared with traditional walk-through thermography, it is much quicker and cheaper to perform. Yet it is currently unclear how successful this methodology is at detecting building defects. This paper qualitatively compares pass-by thermography and walk-through thermography. A set of 122 residential dwellings in South West England was inspected using the both methodologies. Results show that substantially more defects were detected using walk-through thermography, with internal inspections yielding the greatest number of detected defects. Significant constraints with walk-past thermography were identified, such as unknown occupancy behaviour, transient climatic conditions, fixed viewing angles and spatial resolution limitations, which were all found to have a greater impact on image results than during walk-through thermography.Although trends in conductivity defects were found from target comparison analysis between similar dwellings, viewing single external elevations under walk-past thermography was found to miss many different defect types, which would have normally been discovered during traditional walk-through thermography.

a b s t r a c tBuilding thermography traditionally captures the thermal condition of building fabric at one single point in time, rather than changes in state over a sustained period. Buildings, materials and the environment are, however, rarely in a thermal equilibrium, which therefore risks the misinterpretation of building defects by employing this standard methodology. This paper tests the premise that time-lapse thermography can better capture building defects and dynamic thermal behaviour. Results investigating the temporal resolution required for time-lapse thermography over two case study houses found that under typical conditions small temperature differences (approximately 0.2 K) between thermal areas could be expected for 30-min image intervals. Results also demonstrate that thermal patterns vary significantly from day-to-day, with a 2.0 K surface temperature difference experienced from one day to the next. Temporal resolutions needed adjusting for different types of construction. Time-lapse experiments raised practical limitations for the methodology that included problems with the distance to target and foreground obstructions. At the same time, these experiments show that time-lapse thermography could greatly improve our understanding of building transient behaviour and possible building defects. Time-lapse thermography also enables enhanced differentiation between environmental conditions (such as clear sky reflections), actual behaviour and construction defects, thereby mitigating the risk of misinterpretation.

Geopolymers are a novel class of inorganic polymers, which have the potential to replace Portland cement in a number of different applications. Geopolymers can utilise a higher level of industrial by-products than Portland cement blends and numerous studies have concluded geopolymer concretes have significantly lower embodied carbon dioxide than Portland-cement-based concretes. This paper examines the potential for the use of geopolymer binders as a Portland cement replacement in the UK. The quantities of material required, the major sources of these materials, the environmental implications and the barriers to implementation are discussed. Construction Materials Volume 166 Issue CM4