UK has some way to go despite retrofit progress

The effort to retrofit UK homes is ramping up – but without fuller understanding of context may fail to fulfil the wider potential for decarbonising our building stock


  • Matthew Allcock MRICS

04 May 2023

Row of terraced houses

The UK government's mandated 2050 net-zero carbon strategy and directive to Build Back Greener challenges us to retrofit 1.5 homes per minute for the next 30 years, taking a fabric-first approach and providing more efficient space heating.

For this, what may be termed a war effort is required, akin to the response to COVID-19. The scale is enormous; and, although Good Homes Alliance chair Lynne Sullivan has recently argued for the creation of a national retrofit hub, there is much that remains to be done.

At my employer Baily Garner, we are currently seeing a majority of fabric-led approaches using external-wall or cavity-wall insulation complemented by other fabric and ventilation upgrades, with whole-house retrofits tackling heating and certain projects exploring the use of photovoltaic and battery systems.

Wealth of guidance points way forward

Explanations of how net zero relates to retrofit abound. There is not one single mandated definition, and what net zero actually is varies according to who you ask. The UK government's Retrofit for the future guide, the LETI climate emergency retrofit guide, and RICS' sustainability report 2022, all offer valuable insight, as will the latter's forthcoming residential retrofit professional standard.

PAS 2035:2030/2019+A1:2022 Retrofitting dwellings for improved energy efficiency. Specification and guidance has also increased rigour in the standard of retrofit. Written in response to the Each Home Counts review, and supported by TrustMark, the standard is now generally mandated across public-sector projects.

The PAS is still evolving, while other standards such as RICS' Whole life carbon assessment for the built environment are not yet receiving the attention they deserve. Nevertheless, these initiatives are taking the profession in a better direction, with increased awareness and understanding of retrofit and associated issues among clients.

Related article

Retrofit: saving energy and creating jobs

Read more

Variety of funding streams made available

There are also an increasing number of funding streams for retrofit, such as the Social Housing Decarbonisation Fund and the Green Homes Grant Local Authority Delivery scheme, both of which have helped stimulate commissions.

These are now complemented by support for properties with low energy performance certificate (EPC) ratings or that are not connected to the gas grid. People on low incomes can meanwhile apply to the Boiler Upgrade Scheme (BUS), Energy Company Obligation (ECO), and the government ECO+ scheme for private householders.

The industry is moving more and more towards requiring EPC ratings and green mortgages, and the notion of stranded assets looms large. However, despite the Construction Leadership Council's proposed national retrofit strategy, which is now in its second iteration, the message from government continues to be mixed and inconsistent.

Projects and performance on the up

The retrofit agenda has certainly risen up the news: not only because public activism has picked up – in the form of Extinction Rebellion, Insulate Britain and Households Declare protests, for instance – but also because consumers are increasingly feeling the effect of rising energy prices on their wallets.

Numbers of live projects are gaining pace, with the best practice retrofit package becoming steadily refined. Those carrying out retrofits are therefore sharing insights with the rest of the profession at webinars, as well as exchanging knowledge, partnerships and collaboration on the Social Housing Retrofit Accelerator and similar platforms.

Monitoring Baily Garner's own data on retrofits, completed more than a year ago at Sutton in south London, there are indications that they are performing well, with better internal air quality and thermal comfort, and savings of up to 50% on fuel bills relative to current energy cost trends. Altogether, this promises to close both the performance and health gaps.

Installations must be understood in context

However, there are numerous challenges when it comes to installation, including lack of preparedness on the part of clients, professionals and the wider industry – notably, in terms of people with available skills and capacity to do the work.

The retrofit agenda is surely about more than just achieving net zero as well. Biodiversity and embodied carbon do not presently feature in this discussion in any meaningful way beyond the fringes. Serious consideration must also be given to the industry's capacity to install retrofits, and understand and use emerging technologies, as well as the actual condition of our existing stock. Housing providers and asset managers also need to fine-tune their data and understand the baseline they are working from. 

Too many times project teams rush into retrofit projects with data incomplete and existing defects unaddressed, meaning efficiencies cannot be realised and technical and practical challenges increase. This leads to time and cost overruns for remedial works that quite often relate to other budget streams.

Defects in masonry and cavity, timber and foundations as well as any issues with drainage, asbestos, damp and mould all need addressing before any retrofit works are carried out.

Yet strategic asset management, condition-led component replacement, valuing operational and embodied carbon and minimising resident disruption can all be achieved – carefully, but not without challenge – in successful projects.

In embracing retrofit, there is the opportunity to enhance and widen the skills of building surveyors and others, deepen our understanding of embodied and whole-life carbon, and to explore ecology as local planning authorities mandate biodiversity net gain.

'The retrofit agenda is about more than just achieving net zero'

Practical factors affect volatile market

There are also the on-site challenges of retrofit. Every building is different, and turning over someone's house is never easy with residents in situ. When things do go wrong bad news can travel fast, adding to the cost – a significant stumbling block in the sensitive construction market.

Whole-house deep retrofit, which involves treatment of all elements including fabric and services, was once the watchword. But the focus is now shifting towards more targeted lighter-touch retrofits such as upgrading fabric, reducing heat demand, and improving services in a medium-term plan under PAS 2035. Careful assessment of each element's life cycle can effectively inform this process.

Yet pace still remains too slow, with general demand for more sustainable buildings sluggish, as RICS' Sustainability report 2022 makes clear.

Softer skills can help engage householders

So far this article has taken a technical view of retrofit. But what does the word mean for those whose houses are being retrofitted?

Some say the word sounds regressive or techy. So do we need to review the language we use? Would 'sustainable homes' or similar be a better term to employ? Because if residents or owners won't let us into their properties, we are not going to get retrofits done.

Sometimes the process is not understood; neither is certain new technology. Residents may not care for the disruption, and there can be distrust of industry and landlords.

Building surveyors are perfectly placed to communicate with a variety of tenants, and also have the associated technical and project management skills to help run successful retrofit projects. Multidisciplinary teams can help achieve efficiencies and meet demanding timescales, in a variety of capacities.

A wide mix of building types will require retrofitting in the coming years. The challenges in each case will vary and, no matter how far efforts are scaled up, the need for attention to detail and a more particular approach to buildings in situ and people skills cannot be ignored.

'If residents or owners won't let us into their properties, we are not going to get retrofits done'

Conservative sector must become radical retrofitter

Construction has been often called a conservative sector, showing little sign of the radically new low-carbon architecture we need.

Issues with adversarial contracting and the race to the bottom have recently been in the spotlight, but these date back at least to the 1990s when they were identified in both the Latham Report and Rethinking Construction – The Egan Report.

False starts abound, such as the failed Green Deal, the Green Homes Grant, and most recently the challenges faced by the Boiler Upgrade Scheme.

In fact, the UK has the lowest heat pump installation rate in Europe. Even PAS 2035 and similar developments have been a long time coming, with voices for more sustainable building going back decades.

Looking to the past for our future

Or might that be centuries? Perhaps we have a brief window of opportunity – and it is brief because we are now in a climate and ecological emergency – to reclaim historical methods of ensuring building environmental performance.

These might include self-regulating houses, ventilation and heating around the built form, and even panels derived from cocoa crops. These examples may entail reduced energy demand, the re-adoption of more natural and less energy-intensive techniques, and the practical reuse of waste materials.

These are themes that are likely to be picked up at the forthcoming Retrofit 23 exhibition, due to take place in from 10 May to 29 September, at the Building Centre in central London.

Perhaps we also need a new culture better attuned to the changing climate. Alongside a renewed focus on demand-side responses in building and energy use, through smarter grid capacity planning and tariffs, this may help us on that journey to net zero, better buildings and better health – and better project outputs.


Matthew Allcock MRICS is a building surveyor at Baily Garner and a qualified retrofit coordinator
Contact Matthew: Email

Related competencies include: Construction technology and environmental services, Sustainability

Related Articles


go to article When does new safety regime apply to commercial units?


go to article How regulatory reviews help improve valuation practice


go to article What we learned in developing an HRB safety case process