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Karen Fletcher explores whether it is better to demolish or refurb

So, it seems that it’s Michael vs Marks down on London’s Oxford Street this summer. That epitome of corporate good behaviour, Marks & Spencer has somehow got itself into a bit of a tussle with Michael Gove, former Secretary of State for Levelling Up, Housing and Communities.

Gove has taken a run at the much-loved mainstay of the British high street over its proposal to demolish and rebuild its flagship London store.

To be fair, he wasn’t the first to raise questions about the plan (which had been approved at the local level). Campaigners had already claimed that the embodied carbon of the existing building was such that knocking it down would release 40,000 tonnes of CO2.

However, M&S has pointed out that refurbishing such an old building (which is actually three buildings in one) would require far more work and that the replacement store will be in the top 10% of buildings in London for energy efficiency.

It may take time to settle on an agreed approach but the outcome should be a shared understanding

Karen Fletcher Rocket Karen Fletcher Content director Rocket Content

Carbon optioneering

As that argument rumbles on, the City of London is also proposing changes to planning advice to focus on the whole-lifecycle carbon impact of new buildings.

Consultant Hilson Moran has developed a planning advice note on ‘Whole Lifecycle Carbon Optioneering’ which is part of the City’s overarching aim of achieving net zero carbon emissions by 2040.

The focus on embodied carbon is not a new concept for building services engineers, who have been considering its implications for some time.

However, the fact that it is now being raised at government level (and with high-profile projects) shows that the idea is being embraced as a key element of wider net zero policy.

We should expect to see more push-back from planning bodies across the UK in future. Where a new office block may once have been an indication of growth in an area, it may be less favourably viewed than the revitalisation of more run-down buildings.

Challenging concepts

But assessing and comparing the embodied carbon of projects is is easier said than done and explains why we’re seeing confusion and disagreement around the implications of embodied carbon in some high-profile projects.

If an experienced client such as Marks and Spencer, which has been at the forefront of environmental issues for decades, can find itself having problems with the concept of embodied carbon, then there is no doubt other property owners and developers are finding this a challenge.

This is partly because in the past decade our focus has been on the operational energy efficiency of buildings.

This has been supported by updates to Part F of the Building Regulations as well as programmes such as the Minimum Energy Efficiency Scheme (MEES).

And while operational energy use is not always straightforward to calculate, embodied carbon is far more complex.


CIBSE’s guidance on measuring embodied carbon (TM65) gets to the key point: “Embodied carbon in MEP (mechanical, electrical and plumbing systems) makes up a large proportion of building emissions but is hard to measure”.  

The embodied carbon of a chiller or VRF system is made up of the materials used in manufacture, the energy required for production, transport, storage.

It’s a complicated journey from factory to site installation that can also include product replacement and spare parts - as well as issues such as refrigerant leakage and what happens at the end of a product’s life.

One of the potholes on this road is that there is currently no national legislation on embodied carbon.

However there is a proposed Part Z which government seems minded to embrace on the next round of Building Regulation updates. 

The proposed document aligns with RICS guidance on whole life carbon assessment, as well as work by CIBSE, UKGBC and LETI.

Follow the money

Support for the principles of Part Z is not only within the construction sector itself.

Financial investors and landlords are also keen for more clarity and regulation on embodied carbon.

Their interest is understandable. As big money seeks out sustainable investment, it’s crucial that the property sector is open about its carbon impacts.

A clear and agreed approach to providing that information is therefore essential.

Having spent decades getting to grips with the concepts of operational energy use, the building services sector should now expect embodied carbon to be on the list of considerations when it comes to specification of product.

While it may take a while to settle on an agreed approach to calculation, the outcome should be a shared understanding across the construction and property sectors.

Karen Fletcher is former editor of CIBSE Journal and Modern Building Services