Outlook

The national context
We have a particular interest in buildings of traditional construction. Our approach combines respect for longevity and heritage – whether the house is listed or not – with rigorous building physics.

The UK has made foundational commitments to address climate change through the Climate Change Act 2008. Adding to the challenge is the age of our housing stock, the oldest in Europe. Around 6 million homes in the UK were built before 1919 – but solid wall construction continued through the 1920s and 1930s in reduced numbers, meaning the total stock of solid wall properties is significantly larger.

Just as it would not be physically possible or culturally acceptable to replace these old houses wholesale, neither is it tenable to leave their thermal performance unaddressed, in terms of environmental impact and the health and comfort of the people who live in them. 

Retrofit is therefore unavoidable. The practical challenge is how heritage and decarbonisation are reconciled, and how measures are prioritised and sequenced.

The importance of longevity
We recognise the value of longevity in buildings as a good in itself, as well as from a practical, environmental and economic standpoint. As Dr Robyn Pender has written, the French word for “sustainability” is “durability”:

“The most durable building will be the one with the longest usable lifespan, requiring the least energy input for ongoing maintenance and operation.” 

A house which has already lasted 150 or 200 years has proven something important, and we believe that the purely practical achievement of its persistence should be given greater weight. This perspective suggests that the relatively technical practice of heritage protection – such as the control of Conservation Areas and listed buildings – could usefully become broader and more flexible, and is an endeavour we would support.

We argue that retrofit is best understood as an opportunity to extend the life of an old building, and the process should never lead to fabric – already proven as so impressively durable – being prematurely discarded. 

Comfort (just) before carbon
Carbon reduction is essential. The most reliable way to achieve it in older houses is to make them genuinely more comfortable. Sustained carbon reduction typically follows from careful, well-judged interventions aimed first at improving comfort and performance. This approach is informed by John Kay’s argument in his book Obliquity – that complex goals are often best achieved indirectly – and by UK Green Building Council research into homeowner motivations.

Repair, then retrofit – and repair before replace 
Pre-retrofit repairs are foundational, not ancillary – hence our principle: repair, then retrofit. This recognises that the fundamentals of good maintenance are inseparable from the long-term stewardship of historic buildings.

If a typical late-Victorian house, now around 150 years old, can be expected to remain in use for another century or more, this lends environmental and economic weight to the SPAB’s advice to “stave off decay with daily care”. The perspective that there is critical cultural and environmental value in the basic care of old houses is further strengthened when we can note how readily they are able to persist for multiple centuries, far beyond most the timeline of most life cycle assessments.

We support the long-term persistence of historically intact, comfortable and energy-efficient buildings, with longevity, repair and retrofit acting together in mutual reinforcement.

Beyond adversarial thinking – and reconciling environmental and heritage concerns 
Graeme’s research revealed a paradox. While there was some resistance to solid wall insulation, nearly 90% of respondents expressed a desire to improve the energy efficiency of their homes, motivated by reducing heating costs, improving thermal comfort and concern for the environment. 

Rather than discarding aesthetic concerns, we advocate for an approach which integrates heritage values and the practical need for warmth with financial and environmental priorities. Redstart’s work is grounded in striking this balance. 

A pragmatic approach
Poor techniques in the construction industry are widespread and, as Gavin Killip has pointed out, knowledge about how buildings actually perform is still too rarely understood across different trades. Work is typically carried out in silos, with each trade focused on its own task rather than the behaviour of the building as a whole. Damaging modern materials, ill-suited to traditional construction, also continue to be used widely in the repair and renovation of old houses.

At the same time, there is a deep body of knowledge within the heritage sector. However, this knowledge is not always transferred effectively into mainstream construction practice. Guidance can be overlooked, misunderstood or dismissed, and long-standing patterns of work persist.

The result is a gap between what is known about the basics of correct practice, and what is actually practised. Individual tradespeople may be highly skilled, but without a broader understanding of how buildings work, good intentions can still lead to poor outcomes – particularly where energy performance and moisture are concerned.

Bridging this gap is essential. It requires not only technical understanding, but also clearer, more practically grounded communication, alongside mutual respect between disciplines.

We see part of our role as helping to connect these worlds – translating established heritage knowledge into clear, buildable strategies that can be delivered in practice. As Stewart Brand writes in How Buildings Learn:

“Besides gaining the loyalty of their occupants and visitors, old buildings that stay in use rise to other freedoms. By spanning generations, they transcend style and turn it into history. By showing a tangible deep history, the building proposes an equally deep future and summons the taking of long-term responsibility from its occupants.”

The practical task is to improve energy performance while ensuring that these buildings remain well-used and durable for centuries to come.

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