Sustainable bio & waste resources for thermal insulation of buildings

A growing awareness of the environmental impact of construction materials is leading to development of more sustainable building products, with particular attention focussed on bio-based resources and circularity. In recent years the market share of bio-based building products has grown significantly, supported by research on materials such as wood fibre, hemp, and straw bale. At the same time there has been growing awareness of the potential for greater circularity in construction, prolonging the life of existing products and materials, thus minimising embodied carbon emissions of future projects, as well as reducing reliance on primary resources and impact on landfill. This paper presents results of an investigation into the thermal and hygric characteristics of three novel insulation prototypes developed from bio-based or waste-stream materials. The experimental development and characterisation of insulation using maize pith, recycled bedding (polyester duvet) materials, and wheat straw insulating prototypes are presented. Hygric and thermal performance are compared to a mineral wool insulation product. As part of this work a series of large-scale thermal conductivity and hygric investigations were also conducted in which the performance of each insulation product with a timber framed wall was studied under steady state and variable environmental conditions. This work was part of a larger international research project aimed at developing insulating materials from bio-based and waste streams and will support market development of novel materials and products into mainstream construction.