Updated on 14/10/2025
Over 1 in 5 homes and a third of all non-residential properties were built over a century ago in England alone. For this reason, historic buildings play an important role in the UK’s built environment and cultural heritage. However, their sustainability often falls short of modern standards.
While retrofitting historic buildings could generate £35 billion for the economy each year, we need to follow BS 7913: 2013 to ensure that the broadest range of expertise is deployed in doing so.
In this guide, we’ll share key principles for retrofitting historic buildings for sustainability, why this process matters, and the challenges you may face.
What Is a Historic Building?
We can define historic buildings as structures that are historically important or significant due to their age, architectural style or cultural value.
Buildings are typically identified as historic through formal designations such as statutory listing, for example, Grade II, Conservation area status, or assessments following BS 7913:2013.
Why Retrofit Historic Buildings for Sustainability?
Considering the UN’s Sustainable Development Goals and the UK government’s target of net-zero by 2050, retrofitting historic buildings is crucial. Above all, it’s an opportunity to make significant reductions in our carbon emissions.
While buildings account for an estimated 25% of all carbon emissions in the UK, traditional and historic buildings in particular tend to be less energy efficient due to older design and construction methods.
Retrofitting allows us to improve energy efficiency, but only when guided by conservation-led approaches that place historic significance first. For example, following the whole building approach that is outlined in BS 7913:2013 and PAS 2035.
When approached with care, retrofitting can help to maintain a building’s heritage value without compromising its character, keeping it functional for generations to come.
At the Environment Study Centre, we offer the Level 3 Award in Energy Efficiency for Older and Traditional Buildings, which you’ll need to retrofit historic buildings.
Originally developed over 10 years ago, this course is led by Professor John Edwards, the co-author of the RICS Conservation Guidance Note and BS 7912:2013. Professor John Edwards has had input into conservation plans for national landmarks ranging from Cardiff Castle to Somerset House.
Our Level 3 Award will leave you confident in implementing these industry-leading standards in your retrofit projects.
The Whole Building Approach
When it comes to retrofitting historic buildings, conservation professionals advocate a whole building approach.
As retrofitters, we will begin with a Statement of Significance to assess a building’s value before determining any interventions. This step is critical if we are to prevent unintended consequences that may harm the historical building fabric.
A whole-building approach helps us:
- Understand how the building is constructed and the original materials used.
- Evaluate the building’s existing condition and historical significance.
- Identify areas for improvement in energy efficiency and carbon reduction.
- Plan sympathetic interventions with respect for the building’s integrity.
Interventions for Sustainability in Retrofitting Historic Buildings
As we’ve covered, when making interventions to historic buildings, we need to balance heritage preservation with environmental performance.
It’s worth stressing that a Heritage Impact Assessment is needed before any interventions can be made. This enables us to respond appropriately to the building’s historic significance, materials and environment.
Here are five common interventions we can make:
- Insulation: Reducing heat loss across roofs, walls, and floors, while ensuring breathability and preventing moisture issues.
- Draft-Proofing: Sealing gaps around windows and doors can improve energy efficiency and thermal comfort.
- Upgrading Windows: Historic windows can be repaired or upgraded with secondary glazing or specialist slim-profile double glazing to improve thermal performance.
- Lighting & Appliances: We can install modern, energy-efficient options to reduce energy consumption.
- Renewable Energy Integration: Renewable technologies such as solar panels and heat pumps can be installed where possible to reduce a building’s carbon footprint without detracting from its aesthetics.
Difficulties in Retrofitting a Historic Building
Now you understand considerations for retrofitting historic buildings and common interventions, here are some of the challenges you’ll likely face in these projects:
Navigating Traditional Construction Methods
It’s important to understand that traditional and historic buildings were built with different materials and techniques from those used today. Historically, builders and architects often prioritised breathability and flexibility over insulation and air tightness.
Following conservation methodologies is essential, as interventions may otherwise lead to the deterioration of materials, trapped moisture and irreversible damage. This is why we must follow BS 7913:2013 and engage qualified professionals trained in heritage retrofit.
A Shortage in Traditional Building Professionals
It’s estimated we need 86,500 more professionals skilled in retrofitting traditional buildings to reach the UK’s net-zero targets in England alone. There’s a known skills shortage, with the Palace of Westminster’s retrofit threatening to tie up craftspeople for as much as 40 years.
While this skills gap presents an opportunity for retrofitting professionals, it can also pose a challenge in project management when it comes to hiring the workers needed to scale up historical building retrofits.
Not only does it hinder our progress towards net-zero, but the skills shortage in the retrofit of historic buildings also increases the risk of poor-quality work. This is why we’ve designed training pathways, such as our Level 3 Award, to fill this critical gap with guidance based on nationally recognised standards.
Hidden Defects & Unforeseen Conditions
Historical buildings often have hidden issues, such as concealed damp, timber decay or inappropriate past repairs, that only become apparent once retrofit work begins. As these buildings have likely been repaired numerous times over centuries, their true condition might not be fully understood at the survey stage.
This is why comprehensive preliminary investigations, including moisture diagnostics and fabric analysis, are essential before any retrofit interventions take place.
By adopting a whole building approach, retrofit professionals can identify and address these issues early, ensuring that interventions are compatible and sustainable. This proactive process is central to the training we deliver at the Environment Study Centre, giving practitioners the confidence to diagnose, plan, and manage complex retrofit challenges in older buildings.
Permissions and Consent
Planning permissions and consent processes are important steps you’ll need to navigate when retrofitting historic buildings. Whether you’re working on a listed building, conservation area, or a scheduled monument, each will have specific requirements from local authorities and heritage bodies like Historic England.
For example, retrofitting a listed building requires mandatory consent before any work can be started.
When making a consent application, you will need to provide a Design and Access Statement or a Heritage Impact Assessment prepared in accordance with BS 7913:2013. This framework allows you to demonstrate to authorities how your proposals align with significance, context and conservation principles.
How We Can Help
As you’ll have learnt in this guide, retrofitting historic buildings for sustainability is an essential process to preserve our cultural heritage while meeting net-zero goals.
Retrofitting historic buildings involves a holistic approach, balancing interventions with the need to maintain the original character and design of a building.
When you’re ready to learn more, our Level 3 Award in Energy Efficiency for Older and Traditional Buildings offers the skills you’ll need to retrofit historic buildings in compliance with BSI PAS 2035 and PAS 2038.
You can find all our building retrofit courses here, or contact us when you’re ready to begin your studies.
