Jim Hart SBE0089

Written evidence submitted by Jim Hart


Alongside my work as a sustainability consultant I am also a PhD candidate at Edinburgh Napier University, researching the role of biogenic (or nature-based) construction materials in a low carbon economy, so my answer mainly focuses on that question.

Questions & Responses

What role can nature-based materials can play in achieving the Government’s net zero ambition?

Nature-based materials undoubtedly have a role to play, and should be supported, but it is easy to overstate the extent to which material switching can solve our problems. Furthermore, complacency about the benefits of nature-based materials has the potential to lead to some negative outcomes, as a number of traps lie in wait, as follows.



Should the embodied carbon impact of alternative building materials take into account the carbon cost of manufacture and delivery to site, enabling customers to assess the relative impact of imported versus domestically sourced materials?

Yes absolutely. It is essential that as full a carbon account as is practicable is produced for all materials and products under consideration. In some cases this may uncover some unpalatable truths that need to be considered, such as shipment of materials (both biogenic and mineral materials) from Europe to the Far East for processing, and back again.


How should we take into account the use of materials to minimise carbon footprint, such as use of water harvesting from the roof, grey water circulation, porous surfaces for hardstanding, energy generation systems such as solar panels?

In the context of a whole-life carbon account of a building, the embodied carbon of solar panels needs to be evaluated just as the embodied carbon of insulation is. The challenge is the lack of data on the subject, and work is evidently required here. The other features identified (water harvesting, porous paving etc.) should also be included in the account: in such cases the environmental benefits associated with water resources will subjectively outweigh the carbon cost in the better designs, but – either way – the carbon cost should not be swept under the carpet. It would be difficult to quantify the indirect carbon benefits associated with such measures (e.g. the contribution to flood prevention and the destruction of property / resources), so there should always be room for discussion of such points alongside any quantitative analysis.


What can the Government do to incentivise more repair, maintenance and retrofit of existing buildings?


May 2021