Thermal insulation performance assessment of agglomerated cork boards

Over the last few years, the building industry has been focusing on research, on the construction of passive houses and on the use of natural, local materials that are non-toxic, recyclable and can assure high thermal insulation. Cork is a natural material whose qualities have been known since ancient times and which fully meets sustainability requirements. High quality cork is mainly used to produce bottle stoppers. Owing to the manufacturing process, over 75% of it becomes a waste product. Furthermore, a large amount of waste cork comes from industry, from forest cleaning and pruning and from waste selection. Such a material is then recycled and triturated to obtain cork granulate. Cork granulate is a sustainable solution that recycles a waste product, which substantially keeps the characteristics of the original material, and turns it into a resource for manufacturing new products, such as insulating boards made up of cork agglomerate that are increasingly used in the building sector. In this paper, certain thermophysical parameters of six agglomerated cork boards are evaluated. Different constituent characteristics of the boards, such as grain size distribution, density and thickness, were taken into account in order to evaluate how they may influence insulating performances. The tested agglomerated cork boards showed thermophysical characteristics similar to those of the cork bark and even highlighted a higher diffusivity value than natural cork. Ultimately, it may be assumed that the agglomerated cork boards are a suitable and sustainable solution particularly for the thermal insulation of buildings in hot climate areas and where a healthy environment is required.