Supporter's Column: Stephen King

How do we deliver housing at pace whilst fundamentally changing the mode of delivery to achieve net zero?

Housing and Delivery


Our professional leaders have strong aspirations; following the Paris Agreement the RIBA set out the 2030 Climate Challenge and the IStructE made the commitment to treat sustainability and the climate emergency with equal importance to life safety.

However we have not seen a change in the way housing infrastructure is delivered, instead we have seen the cancellation of sustainability codes, collapse of offsite manufacturing firms, reactive policymaking, and the concentration of housebuilding with larger firms. We are currently relying on voluntary design choices to reduce the impact of development, which are often sidelined for ‘traditional methods of construction’ (business as usual). The problem being there is no framework regulation for embodied carbon in the built environment, only the operational carbon through Part L.

Critically, two groups are attempting to establish this framework, through a proposed amendment to the Building Regulations; a new ‘Part Z’, and the UK Net Zero Carbon Building Standard (NZC).

Requiring whole life assessment and limitations on ‘carbon intensity’ in construction, the proposed ‘Part Z’ is a fantastic proposal to bring the industry in line with the 2050 roadmap.  Reintroduced into parliament earlier in 2023, it will hopefully be a success story for the UK, as the global community recognises that addressing embodied carbon is crucial for achieving carbon neutrality and mitigating the environmental impact of the built environment.

In a similar vein, the NZC aims to be the UK's first cross-industry Net Zero Carbon Buildings Standard for all major building types. Being used as a tool to robustly prove that built assets are net zero carbon and in line with our nation’s climate targets, based on a 1.5°C trajectory.

But with great support from industry and professional institutions, why has this not been implemented already as part of the roadmap to net-zero?

Firstly, a shift to construct buildings with materials of low embodied carbon, or which are demountable and recyclable at end of life, will require a fundamental change in architectural context. It would mean switching from heavy and non-recyclable materials such as brick and concrete to lighter or more recyclable materials such as metals, timbers and rendered cladding panels. This can be seen as an issue in communities which are trying to preserve the character of their streets, but also reveals a massive shortage in supply of materials and skills that would be required to deliver our target number of homes each year. Government targets still being 300,000 new dwellings per year.

Products with low embodied carbon are often made of recyclable or renewable materials, which can form part of the circular economy, or are manufactured with renewable energy sources; hence they come with a price premium as the materials have a longer life span, can be fully recycled/reused and perhaps avoid carbon taxes/offset costs. So perhaps the options are there, but developers aren’t incentivized to pay for it.

If we passed the proposed Part Z, delegated powers to our local authorities and give them some teeth to make polluters pay by raising a carbon tax on development, it could prove to be the incentive that developers need to ensure our housing infrastructure is kickstarted into a sustainable future.

Finally, architects and engineers must prioritise environmental performance. This shift requires a departure from the conventional emphasis on aesthetics and cost considerations alone, towards an integrated approach that may involve revisiting design principles, influencing local planning policy, utilising recycled or locally sourced materials, and promoting modular construction to reduce waste. Architects and engineers need to adopt a life-cycle perspective, it is essential to understand how the building is assembled, and disassembled at the end of life. 

If you have signed up for Architects or Engineers Declare, I would urge you to also get behind the proposed part Z – and catalyze this change! Ensuring a collective commitment to reduce the embodied carbon of buildings.


Written by Stephen King, Director at Lewis Hubbard Engineering.