Building the green dream

31st May 2024

A system-level review is needed to deliver a large-scale programme of retrofit for existing buildings. Failure to do so will risk missing net-zero targets, argues Amanda Williams

The building and construction sector contributes significantly to climate change, accounting for about 21% of global greenhouse gas emissions. In 2022, buildings were responsible for 34% of global energy demand and 37% of energy and process-related carbon dioxide emissions, according to the UN’s latest Global Status Report for Buildings and Construction, released in March 2024.

The good news is that the construction industry is well positioned to make a significant contribution to this challenge. It is a diverse industry, with a wide range of knowledge and expertise, and well used to collaborating across disciplines. We know we must build for a sustainable future, because what we build today will shape our tomorrow, but there is also a large opportunity and pressing need to improve existing building stock.

An urgent need to retrofit

According to the Net Zero Carbon Guide, 80% of the buildings we use today will still be in use in 2050, so failure to deliver a large-scale programme of retrofit for existing buildings will put our net-zero targets at risk. Retrofit is aimed at increasing the energy efficiency of existing building stock by adding technology or equipment that was not included at the point of construction, such as improvements to the building fabric (including insulation, draught-proofing, double-glazing) and new building systems (such as heating and hot water, ventilation or renewable energy systems).

As well as reducing carbon emissions, this will lower energy bills and improve health and wellbeing for building occupants. It allows us to extend the life of existing structures, while bringing them up to modern standards, and if combined with measures to repurpose a building, can also facilitate reuse. Retrofitting also avoids the carbon emissions associated with demolishing and building new – most notably, the embodied carbon in cement and steel.

Retrofit could help to address social inequalities. For example, the UK government’s Housing Statistics for Rural England, published in November, highlighted that more than 90% of the rural population who live in pre-1930s properties are in homes with an energy-efficiency rating low enough to put them at risk of fuel poverty. The report showed that rural properties are getting left behind in the push towards energy efficiency.

There is also work to be done to retrofit existing buildings for resilience to increasing climate hazards, such as structural hardening to protect against climate-related damage, and work to improve energy supply resilience through renewable energy generation and storage.

Despite the clear benefits, the rate of retrofit in buildings is well below what is needed. Currently, the average retrofit rate of the building stock is around 1% per year, with these retrofits typically achieving less than a 15% reduction in energy intensity. To align with the goals of the Paris Agreement, retrofit rates need to increase to 2.5%-5% and higher by 2030, and these retrofits need to be extensive. That’s according to the UN’s Global Status Report for Buildings and Construction.

However, there are some significant challenges. Existing building stock in the UK, for example, is extremely varied, in terms of building typology, age and quality, and comes with varying degrees of building information. This requires a tailored approach, because a poorly managed and implemented retrofit can damage the fabric of the building or lead to other unsatisfactory outcomes, such as problematic internal environmental conditions and issues like condensation and mould. Careful assessment and informed design are essential.

A massive shortage of skills

The scale of the challenge was highlighted by a recent report from Whole Life Consultants on behalf of Central London Forward, the organisation which represents the 12 central London local authorities. They estimated that retrofitting every property in the capital with existing energy performance certificates of C to G would require 148,000 person years of labour (equivalent to the output of 148,000 people working full-time for a year). Depending on the pace of rollout, by the end of the decade, a workforce of between 19,000 and 28,000 skilled workers would be required to deliver retrofit in central London alone.

“Rates of retrofit recruitment must triple if the country is to meet its 2050 net-zero target”

This brings us to a key challenge, which is the skills shortage. Last year, Reed Environment shared new research estimating that rates of retrofit recruitment must triple if the country is to meet its 2050 net-zero target. It argued that if these rates don’t increase, the UK won’t achieve its target number of energy-efficient installations to meet its net-zero goal until 2105 – 55 years beyond the 2050 target date.

Retrofitting requires skilled workers, regardless of the age and construction of a building. But adapting historic buildings requires even more specialist skills and training. That’s why the Chartered Institute of Building (CIOB) has added a retrofit pathway to its Building Conservation Certification Scheme and has published a new Technical Information Sheet on Retrofit of Buildings that explores some of these issues.

The construction industry is currently experiencing a general shortage of skilled labour, and particularly in relation to green skills. A potential solution is to close the loop between the need for a just transition for workers in industries that need to be scaled down in the face of global climate crisis and the skills shortage in construction, with the built environment becoming a destination industry for those with transferable skills or access to retraining, ensuring we have the workforce to drive this forward.

Calls for a retrofit strategy

The appetite for learning is out there. The CIOB Academy saw demand for building conservation learning soar between 2018 and 2021, given the rising prominence of conservation and retrofit particularly. And other providers such as Scotland’s Built Environment – Smarter Transformation are seeing increasing demand for their low-carbon learning, Passivhaus standards and retrofit training courses.

The CIOB has long called on government to adopt a national retrofit strategy for the UK, setting out how this transition will be achieved. This must address homeowner/property-owner confidence; the funding gap; skills, training and accreditation; standards, quality and compliance; and provision of advice.

This is a key area of work for the CIOB policy team, which has also made the case for using VAT changes to provide an incentive for retrofitting over demolition; advocated for a ‘help-to-fix’ scheme, which would provide an interest-free government loan to cover the homeowner costs of improvements; and argued in favour of deferring stamp duty on properties that have been purchased with the sole purpose of refurbishment.

The challenges must not be allowed to be a barrier to retrofitting existing properties, which can and must be done to a high standard and at an increasing pace. The scale and complexity of this challenge is daunting, but what is required (both in the UK and elsewhere) is to take a step back and look at this holistically at a system level to identify the dependencies between different areas of challenge. This will enable informed decisions about the strategic interventions needed to deliver the desired outcomes, including how to unlock the personnel and skills to bring our homes and workplaces up to a standard fit for the future.

Amanda Williams FIEMA CEnv is head of environmental sustainability at the Chartered Institute of Building


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