With the Future Homes and Buildings Standards coming into force next year, Donaldson Timber Systems technical director, John Smith, explains why using current standards, there’s still a risk that new buildings may never achieve true zero carbon.
At the end of March, the government published the long-awaited Future Homes and Buildings Standards (FHS) that will come into force on 24 March 2027 and will apply from March 2028. According to the policy’s impact assessment, these regulations are a crucial part of the government’s bid to meet the target of net zero greenhouse gas emissions in the UK by 2050.
While this is a three-year delay from the original plans and nearly a decade after the government first committed to the policy, it’s great to see this moving forward, and is a step in the right direction towards achieving Net Zero. But, it is by no means, the final picture when it comes to the UK’s net zero journey.
There is one key piece of the puzzle that is often ignored when considering Net Zero, and that is embodied carbon. The FHS specifically excludes embodied carbon and focuses on reducing operational carbon (energy required for heating, lighting and hot water). But the reality is, without measuring and reducing the cradle to grave impact of a build, there is a very real risk that buildings constructed to new standards from 2027 and beyond won’t achieve true zero carbon.
What is embodied carbon?
Embodied carbon is the total greenhouse gas emissions generated during the construction and demolition phase. It is calculated in two separate elements: from raw material extraction through to construction of the building on site, including fuel and power for transport, factories and plant; and end-of-life emissions from demolition, transport from site and recycling / landfill.
In a new home completed to 2021 standards, embodied carbon is around 15-20% of the whole life emissions, with the rest from operational carbon. With the target to reduce emissions by 75% through operational carbon reductions, once the FHS is in place, embodied carbon becomes much more significant: by 2028, embodied carbon will be the biggest emitter of emissions over the lifetime of the house.
Despite this, embodied carbon emissions are currently unregulated in the UK construction industry, with only voluntary measurement and mitigation required.
The UK is seriously lagging behind in this area. The Netherlands and Sweden already have mandatory embodied carbon requirements for all new buildings, with Denmark and Finland following suit. In France, embodied carbon in housebuilding has been regulated since 2022. This regulation addresses the entire life cycle of buildings and requires developers to measure both operational and embodied carbon. To comply, developers must perform Life Cycle Assessments (LCA), which evaluate environmental impacts from raw material extraction through to demolition or reuse.
While the FHS is a much-needed step in the right direction, more clarity is required on what it means to be ‘carbon neutral’. The UK government doesn’t give a one-line definition, but when it passed the Climate Change Act in November 2008 (updated in 2019), the concept was described as ‘reducing greenhouse gas emissions to as close to zero as possible and balancing any remaining emissions by removing an equivalent amount from the atmosphere.’
The lack of focus on embodied carbon is a real risk to being able to achieve net zero by 2050. You can green the grid as much as possible and could, in theory, have no operational carbon emissions from living in a home. But the house still needs to be built.
Fundamentally, the FHS has a major flaw. It aims for homes to be ‘zero-carbon ready with no further work needed’, yet by using these incomplete measurements, the carbon in the fabric will not be offset by even the greenest energy without improvements to the insulation and air-tightness.
The solution
As demonstrated elsewhere in Europe, the only way to achieve zero carbon is to measure and reduce the whole-life carbon of buildings. The availability of environmental product declarations (EPDs) is an important step in recognising this, providing accurate and verified information for the specified products and materials. An EPD communicates the environmental performance of a product over its lifetime, making it possible to compare the impacts of different materials and products accurately and allowing customers to select the most sustainable option.
At Donladson Timber Systems, we’ve invested in this process for all our products and were proud to be the first timber frame manufacturer to offer a published EPD for an off-site assembled timber frame wall panel. We always champion the use of offsite timber frame as the best way to achieve sustainable building practices, but a verified EPD proves these claims.
When we factor embodied carbon into the zero-carbon journey, timber comes into its own. Life cycle studies of timber frame homes show that they significantly outperform alternatives – saving around 40% of emissions in comparison to concrete and 30% compared to steel.
Timber frame properties are more sustainable during the build, when in use and throughout the lifetime of the home. Timber can also lower or offset its embodied carbon thanks to sequestration, absorbing one tonne of CO2 while the tree is growing, in every m³ and storing it over the life of the building.
Our Sigma® II closed panel solution achieves FHS fabric performance from the factory, with no additional works required on site, and crucially, very low levels of embodied carbon.
With sustainability targets to reach, a shortage of good quality housing and the future of the planet at stake, embodied carbon must be added into the equation and legislated. If not, we will never achieve true zero carbon homes.