The role of natural materials in low carbon architecture

Justification of paper: The majority of research on natural materials is specific to a single material and solving a particular technical challenge. This paper takes a much wider scope and questions the overarching role... [ view full abstract ]

Justification of paper: The majority of research on natural materials is specific to a single material and solving a particular technical challenge. This paper takes a much wider scope and questions the overarching role natural materials could play in constructing lower embodied carbon buildings.

Purpose: This paper debates the role that natural materials could play in forming the built environment.

Theoretical framework: Research has shown that embodied carbon can typically account for 30% of the whole life emissions of a house and 45% of whole life emissions for an office (Sturgis & Roberts, 2010). This percentage contribution will only increase as legislation moves buildings towards lower operational energy. Embodied carbon is therefore the next likely target for reduction. Reducing this will require using less energy intensive materials within construction (Allwood & Cullen, 2012); one option to achieve this is to replace these with natural, low carbon materials. However, in the UK, construction with natural materials is far from mainstream, this paper explores if they have the capacity and potential to become a common building type.

Results and Conclusions: The following natural building materials are explored: timber, straw-bale, hemp-lime and rammed earth. Different material properties and embodied carbon are compared and contrasted, leading to a discussion on the building or component type they are best suited to. The availability and potential competition for land-use is also considered, with the implications this might have for significantly scaling up the use of these materials debated. Finally the architectural quality and phenomenological feel of these materials is pondered.

Implications for Tipping Points: To effectively reduce carbon emissions the whole building life cycle should be targeted, including embodied emissions. One solution is to increase the use of low carbon materials. This paper explores the extent to which natural materials could form a part of the built environment, moving the built environment towards a sustainable future.

Key words: Timber, straw-bale, hemp-lime, rammed earth