Decarbonising the fit out sector: creating net zero-enabled office spaces
When it comes to cutting whole life embodied carbon, commercial office fit outs lag behind other construction sectors. New solutions, attitudes and guidance is emerging to revolutionise and decarbonise the sector, as Lauren Lemcke, Danielle Rowley and Dave Cheshire report.
Current situation in the sector
Fit outs have shorter lives than the shell and core of a building. As they are typically tied to specific tenants, carbon-intensive office elements from flooring to lighting, ceilings to air conditioning systems are often discarded and replaced far earlier than their natural operational lifespans.
These rapid replacement cycles mean that the embodied carbon emissions, raw material demand and waste arising from fit outs quickly surpass that of the shell and core over a building’s life.
The embodied carbon footprint of fit outs is also difficult to fully quantify. Incoming tenants rarely comprehensively track what they have stripped out, and what they have replaced existing materials, products and building materials with. As a result, there is a lack of knowledge and evidence of the true embodied carbon cost of the sector.
Incoming legislation to drive change
The forthcoming release of the complete Net Zero Carbon Building Standard (currently in pilot form) is expected to set ambitious embodied carbon targets for fit outs, which will be challenging for some aspects of the industry to adapt to. Under the Standard, acceptable embodied carbon targets reduce year-on-year. This calls for substantial and consistent decarbonisation over time: the standard’s upfront embodied carbon limit for a whole office (including shell and core) completing in 2050 is just 60kg of CO2/m2, compared to 735kg of CO2/m2 in 2025.
As a result of this clear standard emerging, it is likely that developers will take a stronger view of what their tenants can put in their buildings to try and minimise strip outs for the next tenant. While ownership of the embodied carbon involved in a new fit out sits with the tenant, we forsee greater numbers of landlords start to decrease the carbon footprint of their building to meet investor and environmental, social and governance demands.
Designing out embodied carbon
Factoring in cost and carbon from the outset is key to an efficient, net zero-enabled fit out solution. Often, driving down carbon can lead to cost savings, but it is vital that this is calculated and communicated early. The key questions to ask are: ‘what can be re-used, re-purposed, or de-selected in favour of a lower-carbon material or process?’
Decarbonisation of a fit out can be approached at three levels. Strategic decisions on retention and reuse is the primary method.
The second level is systems selection, opting for systems that use considerably less embodied carbon.
The final level is component selection. At all levels, cost cutting and carbon cutting typically go hand in hand, as reductions in materials mean reductions in both project cost and embodied carbon content.
Typical elements of a fit out should be considered in turn and in interplay with other elements. Raised access floors, suspended ceilings and partitions can be retained. Existing room layouts can be kept, as can meeting room pods. Every element can be interrogated: is a metal ceiling necessary? Is the existing kitchen functional? Is a new glass meeting room wall needed, or can the existing one be rebranded to fit the client’s requirements?
Designing for disassembly is an essential element of a whole-life approach, allowing components and materials to be reclaimed for reuse at end of first life. Wet trades and chemical bonded joints should be designed out and replaced with reversible, mechanical connections.
This approach also enables ease of reconfiguration of interior spaces: designing in flexibility can also help increase the longevity of a space. Dry-lay floor tiles, for example, do not require VOC-heavy grouts, sealants or adhesives and provide fast, clean installation and de-installation.
Making the most of existing MEP
Retrofitting existing office buildings often involves ripping out and replacing mechanical, electrical and plant (MEP) systems, which has a significant embodied carbon impact. To decarbonise the MEP aspect of a fit out, a staged approach is recommended:
- The first step is to retain the existing system and optimise the system performance to reduce operational energy use before considering replacing any MEP systems. This could include adjusting controls, upgrading older equipment, and ensuring the building is operating as efficiently as possible.
- Only after operational improvements have been made should the focus shift to replacing MEP systems. The aim is to minimise the amount of demolition and replacement required, reusing or refurbishing equipment where possible.
- Where new products are used, opting for more sustainable materials such as cardboard and fabric duct work can help reduce embodied carbon. These products are emerging on to the market as viable alternatives to plastics and metals.
Changing values
The fit out sector is asking existential questions of itself. How do office strip-outs work in an industry which must carefully conserve resources if it is to decarbonise?
Change needs to be systemic. Everyone must be along for the ride – the decarbonisation of the fit out sector will not be achieved in isolation, by a handful of clients, manufacturers, or service providers. Buy-in is required from all parties in a project and across the industry.
We are moving away from an emphasis on the shiny and the brand-new. Instead, increased value is being placed on intelligent, resourceful, imaginative uses of what we already have – valuing existing products and fit out elements as tried and tested, instead of used. The result is good-looking, fit for purpose, net zero-enabled office spaces.
About the cost model: Low carbon office fit out
The cost model (below) is based on a category B commercial fit out of 3,084m2 GIA over two floors in central London. It assumes the previous tenant fit out had not been stripped out, therefore providing an opportunity for maximising reuse and minimising new intervention.
A cost model and upfront carbon model has been provided based on reusing as much of the existing fit out as possible. This includes the reuse of existing partitions, meeting rooms, doors, raised access flooring, suspended ceilings and a part replacement of the existing kitchen.
Click here to download the cost model.
This is an abridged version of an article that was first published in Building magazine. You can read the full article and download the cost model here.