James Wilson                            SBE0085

Written evidence from James Wilson

 

  1. To what extent have the Climate Change Committee’s recommendations on decarbonising the structural fabric of new homes been met?

 

The CCC recommends that reduction in energy use can be achieved by shifting heating demand and preheating homes. This can only be affective by closing the performance gap currently seen in thermal performance in new & existing buildings. Studies show that bio-based/ecologically sustainable materials closer match the manufacturers test data than their high embodied energy equivalents (Walker & Pavia, 2015).

Robust & long term training is required for the construction industry along with policy that supports the use of low embodied energy (from manufacture) building materials. Policy should support primarily generating “negawatts” – energy not used, rather than focusing on decarbonising heat.

 

 

2. How can materials be employed to reduce the carbon impact of new buildings, including

efficient heating and cooling, and which materials are most effective at reducing embodied

carbon?

 

With an increase focus on airtightness & thermal performance comes an increased risk of moisture related problems within a building. Increased moisture can lead to an underperformance of the building fabric especially if using vapour tight building systems. Bio-based and ecologically sustainable building materials offer mechanisms to buffer moisture with the building fabric helping to maintain year round as designed performance levels. Thus reducing heating & cooling loads.

 

For a given U value of 0.15 W/m2K expanded polyurethane foam insulation emits over seven times the amount of CO2 as a flax fibre insulation. Polyurethane foam +150 kgCO2e, Flax 20 kgCO2e (Greenspec, 2021)

 

 

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

 

Reduce whole life cycle embodied energy of buildings, create jobs through new product development and production and installation. Improve indoor air quality reducing respiratory illnesses reducing demand on NHS.

 

 

4. What role can the planning system, permitted development and building regulations play in

delivering a sustainable built environment? How can these policies incentivise developers to use low carbon materials and sustainable design?

 

Building regulations & planning policy should support the use of nature based materials. The example of the building regulations that require a minimum of 50% of materials to be of timber and other natural materials is a good example. This should also be supported by materials passports & buildings being designed for deconstruction and reuse to maintain the highest value for materials being recovered on demolition.

 

 

5. What methods account for embodied carbon in buildings and how can this be consistently

applied across the sector?

 

There are a number of quantitative assessment tools for measuring embodied carbon in buildings BREEAM, ICE, EPD etc. There needs to be a standard method for assessment, that is independent of influence from product developers. Grassroots organisations such as AECB have developed tools for assessing whole life embodied carbon. These organisations should be involved in the development of such sector wide tool.

 

6. 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?

 

There is no reason why the UK needs to rely on imported natural building materials to meet demand. An increase in the use of bio-based natural materials can support a new building component manufacturing industry. Policy should also support the use of materials close to the site of end use. This is well demonstrated with the use of earth building. Marginal land can be used for growing crops for this new industry (Aberystwyth University, 2017).

 

The UK is already reliant on imports of building products from Europe. Imports of plasterboard in 2017 showed a 3:1 import to export ratio (Monthly Stats of building materials and components, BEIS, 2018)

 

https://www.aber.ac.uk/en/news/archive/2017/09/title-206144-en.html

 

7. How well is green infrastructure being incorporated into building design and developments to achieve climate resilience and other benefits?

 

There needs to be more focus on the use of circular, natural materials & their benefits. The use of natural materials to build & retrofit schools & public buildings should be a prerequisite. VAT incentives for using materials with low embodied energy that increase biodiversity, create healthy indoor environments.

 

 

8. 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?

 

Avoid building on high risk sites. Considered design for water attenuation & recirculation. Heat recovery from waste water. Create urban waterways as part of pedestrianisation plans, incorporate SUDS into parkland in urban areas.

 

 

9. How should re-use and refurbishment of buildings be balanced with new developments?

 

Demolition should be a very last resort. The refurbishment of existing buildings should be considered first.

 

 

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

 

0% VAT on deep retrofit as is the case for new build this could be run with the aid of PAS2035.

 

May 2021