Beyond “Heritage Style”: Rethinking Rooflight Specification in Historic Buildings

By Paul Trace, Director, Stella Rooflight.......  

Over the past decade, the specification of rooflights in historic and sensitive buildings has evolved significantly. Advances in performance, detailing and thermal efficiency have  broadened what is possible, while planning authorities and conservation officers have  become increasingly familiar with rooflights as a legitimate way to introduce natural light  into traditionally challenging spaces. 

Alongside this progress, however, a subtle shift has taken place in how suitability is assessed.  Terms such as “heritage style” are now widely used to describe products intended for  conservation contexts, often implying that visual similarity alone is sufficient justification for  their use. While appearance is clearly important, this trend risks oversimplifying a far more  complex set of considerations rooted in material performance, longevity and long term stewardship.  Heritage is not a look to be applied. It is a responsibility, and one that extends well beyond the moment a project is signed off. 

Conservation as stewardship, not replication 

Historic buildings are not static artefacts. They are layered structures shaped by centuries of use, adaptation and repair. Every material introduced today becomes part of that ongoing story and, in time, part of the fabric future custodians must manage. True conservation has always been about stewardship rather than replication. It asks not only how an intervention appears at the point of installation, but how it will behave, age and endure over decades.

This distinction matters because many modern components are designed around relatively short replacement cycles, whereas historic buildings were never intended to be subject to frequent intervention. Roofscapes in particular demand careful consideration. They are among the most visually sensitive elements of historic buildings and are exposed to the harshest environmental conditions. Materials introduced here must do more than look appropriate on day one. They must withstand prolonged exposure, weather predictably and remain stable over the long term, often with limited opportunity for easy replacement. 

Day one acceptance versus long term impact 

Much of the discussion around rooflights understandably focuses on initial appearance. Sightlines, reflectivity, profile depth and proportion all play an important role in determining whether an intervention is visually acceptable. But conservation decisions rarely end at completion.

A more searching question is how a rooflight will perform and appear after twenty, thirty or fifty years in situ. Different materials age in very different ways. Some weather gradually and consistently, developing a surface character that feels increasingly at home within traditional roofscapes. Others rely on finishes or coatings that can degrade unevenly, leading to visual inconsistency or functional failure far sooner than expected. In modern buildings, replacement may be inconvenient. In historic buildings, it is often disruptive, costly and complex.

Access can be difficult, planning approvals may need to be revisited, and disturbance to historic fabric is rarely trivial. What initially appeared to be a modest intervention can quickly become disproportionate. From a conservation perspective, longevity is therefore not simply a performance metric. It is a measure of how respectfully a modern intervention allows a building to continue its life with minimal disruption. 

Reframing cost as risk in today’s financial reality 

Any discussion of specification must acknowledge the economic environment in which the construction industry currently operates. Across the UK, building projects are facing sustained cost pressures driven by labour shortages, wage increases, material price volatility and constrained margins. Recent forecasts suggest that building costs and tender prices are set to rise further over the coming years, reflecting structural pressures rather than short term fluctuation.

At the same time, recent budget decisions have increased employer costs, adding further strain to an industry already operating within tight financial parameters. In this context, it is entirely understandable that clients and project teams scrutinise upfront costs closely. Every specification decision is evaluated through the lens of immediate value for money. Products that appear cost effective at purchase price inevitably attract attention. However, in historic and listed buildings, this narrow focus can obscure the longer term risk profile of a decision.

A component that performs adequately in the short term but requires premature replacement can introduce significant future costs, not just financially, but in terms of programme disruption, planning complexity and impact on historic fabric. Seen this way, cost should be understood not only as an expense to be minimised, but as a proxy for long term risk. Materials and systems that prioritise durability and predictable ageing reduce the likelihood of repeat intervention at a time when budgets, resources and regulatory capacity are already under pressure. 

The rise of “heritage style” products 

At the same time, the marketplace has seen a noticeable increase in products described as “heritage style”. In many cases, this reflects manufacturers seeking to expand their portfolios into what is perceived as a resilient or specialist sector, often driven by price sensitivity and volume.

There is nothing inherently wrong with broader market participation. The challenge arises when heritage suitability is defined primarily by visual cues, without sufficient consideration of material longevity, ageing behaviour or long term compatibility with historic structures. Surface similarity can be persuasive in planning submissions, particularly where time pressures limit deeper interrogation.

Yet heritage performance cannot be assessed on appearance alone. A product may satisfy an aesthetic requirement today while creating avoidable challenges decades later. This trend highlights the importance of informed specification. It is not about restricting choice, but about ensuring that decisions are grounded in a clear understanding of long term consequences, rather than short term visual reassurance. 

Thinking in decades, not product cycles 

Conservation is, by its nature, an intergenerational discipline. Decisions made today will be inherited by future owners, architects and conservation officers, who will judge them not by intention, but by outcome. The most successful interventions are often those that attract the least attention over time.

They age quietly, perform reliably and do not demand repeated intervention. They become part of the building’s fabric rather than a recurring problem to be managed. As discussions around rooflights in historic buildings continue to evolve, there is an opportunity to move beyond the language of “heritage style” and towards a more meaningful consideration of heritage impact. Longevity, material integrity and long term performance should sit at the centre of that conversation.

By thinking in decades rather than product cycles, and by reframing cost in terms of risk and legacy, we can make specification decisions that genuinely respect the buildings entrusted to us. In doing so, we protect not only individual projects, but the integrity of our built heritage for generations to come. To find out more about genuine conservation rooflights for your project contact the Stella Rooflight team on 01794 745445 or email info@stellarooflight.co.uk  

www.stellarooflight.co.uk

Cutting Corners Costs More: Lessons From ECO4 For The Conservation Retrofit Sector

By Paul Trace, Director, Stella Rooflight - When the government launched its latest wave of retrofit initiatives, from the Energy Company Obligation (ECO4) to the Great British Insulation Scheme, the goal was admirable: improve the energy efficiency of the nation’s housing stock and accelerate progress towards net zero.

Yet, the recently published audit findings paint a very different picture. According to data analysed by Refurb & Retrofit, an astonishing 92% of external wall insulation installations inspected under ECO4 were found to have major technical non-compliance issues, with 27% of internal wall insulation projects suffering similar failings. In some cases, poor workmanship or inappropriate materials have left homeowners facing damp problems, trapped moisture, and damaged building fabric, the very issues these schemes were meant to prevent.

These numbers are shocking, but not surprising. They are the predictable result of a system designed around volume rather than quality, a culture of box-ticking, subcontracting and cost-cutting that prizes speed and budget compliance over craftsmanship and accountability. And nowhere are the consequences of that culture more dangerous than in the world of heritage retrofit. 

The danger of “cheap wins” in conservation work 

Heritage and traditional buildings form a vital part of the UK’s built environment, representing not just architectural value but cultural identity. Yet these structures are often among the hardest to retrofit successfully. Their construction methods, materials, and moisture behaviour differ fundamentally from modern buildings, and their aesthetic integrity is protected by planning and conservation controls for good reason.

When you apply the same “one-size-fits-all” mentality that has failed so dramatically under ECO4 to this type of building, the results can be catastrophic. I have seen countless examples where value-engineering, (the polite industry term for cutting corners!), has stripped a project of its integrity. A conservation-area roof converted with standard off-the-shelf aluminium rooflights; a listed barn punctured by PVC imitation products; stainless steel replaced with mild steel to “save a bit on the budget”.

These might look like small changes on paper, but in practice they often compromise both the building’s performance and its authenticity. Once you introduce the wrong material or detailing into a heritage roof, you change its entire behaviour. Moisture movement, expansion and contraction, corrosion, and even colour mismatch can all affect how that element performs and how it weathers over time. In conservation work, what may seem like a cost saving often leads to higher long-term repair costs, and sometimes irreversible damage. 

Lessons from ECO4: systems without scrutiny 

The ECO4 audit results are a warning about what happens when oversight, competence, and accountability are diluted. The retrofit sector has become littered with acronyms, schemes and certifications that promise quality assurance but often deliver little more than bureaucracy. Installers rush to meet volume targets; assessors approve designs remotely; and contractors under price to win work, relying on substitutions and short cuts to recover margins.

The outcome is predictable, systemic underperformance. That same pattern occurs in parts of the construction and heritage sectors whenever decision-makers prioritise upfront savings over long-term value. For instance, substituting a properly engineered 316L stainless-steel conservation rooflight for a cheaper mild steel or aluminium imitation might trim a few hundred pounds off a specification. But over the lifespan of the building, the consequences are clear: corrosion, water ingress, failed seals, discolouration, and in many cases, replacement within a decade.

In contrast, a correctly detailed and installed stainless-steel unit can last the lifetime of the building with minimal maintenance. It’s a textbook example of what economists call false economy, and one that the ECO4 report has just demonstrated on a national scale. 

Heritage retrofit demands skill, not shortcuts 

True conservation is about more than visual replication. It’s about respecting a building’s materials, structure, and performance, and intervening in ways that preserve rather than undermine them. That demands knowledge, skill and time. Unfortunately, those are precisely the things that are hardest to account for in procurement frameworks designed around lowest cost. When funding models or tender criteria reduce heritage retrofit to a tick-box exercise, the industry inevitably responds with standardised, lowest-price solutions. 

Yet, heritage buildings rarely conform to standard. Their roof pitches, joist spacing, or internal liners might all vary subtly, meaning that a “standard size” or “universal fit” product rarely integrates properly. That’s why bespoke manufacturing remains essential in conservation work. A handcrafted rooflight, built precisely to fit the existing structure, respects the fabric of the building and avoids the need for invasive alterations that compromise integrity.

There’s a craft dimension too. When installers are trained in heritage methods, traditional leadwork, correct flashing detailing, or the use of breathable finishes, the results speak for themselves. But when untrained contractors attempt to install conservation features using modern methods or incompatible materials, the failures may take years to surface, long after the project has been signed off. 

The hidden costs of “value engineering” 

The phrase “value engineering” was once about intelligent design optimisation. Today it’s often shorthand for “how can we make it cheaper?” On a spreadsheet, replacing a bespoke stainless-steel rooflight with an imported aluminium version might look like sensible rationalisation. To a client unfamiliar with the materials, both may appear similar in shape and function. But the performance differences are profound.

Aluminium, particularly in coastal or exposed locations, is highly susceptible to corrosion when coatings fail. Condensation within roof cavities can accelerate degradation, leading to frame blistering, leaks, and staining. From the ground, these defects might appear as minor blemishes; up close, they often reveal serious water ingress and decay around rafters or plasterwork. In contrast, marine-grade stainless steel offers exceptional resistance to corrosion, even in harsh environments.

Combine that with proper glazing specification, such as self-cleaning, solar-control glass, and a building gains not just durability but enhanced comfort and sustainability. That’s the irony of cost-cutting: by stripping away quality materials, you often increase a building’s whole-life carbon footprint, maintenance requirements and replacement frequency. It’s the polar opposite of what a sustainable retrofit should achieve. 

Trust, craftsmanship, and cultural change 

If there’s one positive message to take from the ECO4 revelations, it’s that scale without standards doesn’t work. Ambitious sustainability goals are meaningless unless the delivery mechanisms are grounded in competence, craftsmanship, and trust. For heritage and conservation buildings, those values are already embedded in best practice. Conservation officers, architects, and specialist manufacturers understand that longevity and authenticity go hand in hand. But for this ethos to survive, clients and contractors need to resist the temptation to “do it cheaper”.

Retrofit must evolve from being seen as a commodity to being understood as a craft, one that values durability, design integrity, and technical excellence. At Stella Rooflight, we’ve built our business around that principle. Every rooflight we make is individually manufactured to order, using 316L stainless-steel frames, hardwood liners, and glazing options selected for the building’s specific needs. That approach isn’t about luxury; it’s about doing things correctly. In conservation work, correctness is sustainability, because it ensures the building, and its components, last for generations. 

A call for quality over quantity 

The failures of ECO4 and the Great British Insulation Scheme should be more than a cautionary tale, they should be a turning point. Retrofit, whether for energy efficiency or conservation, is not a numbers game. It’s a stewardship responsibility. If we are serious about decarbonising Britain’s building stock, we must stop treating retrofit as a race to the bottom. Architects and specifiers have enormous influence here.

Every time a specification retains the correct heritage material rather than an imitation, it sends a signal that quality matters. Every time a practice chooses a trusted local specialist rather than the cheapest national installer, it helps rebuild the culture of competence our sector so urgently needs. Because in the end, whether you’re insulating a post-war terrace or restoring a Georgian farmhouse, the same truth applies: cutting corners always costs more. And for heritage buildings, those costs are not just financial, they are cultural, architectural, and irreversible.  www.stellarooflight.co.uk

Delayed, Derailed And Devalued: Paul Trace at Stella Rooflight Discusses How The UK's Planning Crisis Is Undermining British Manufacturing

A recent Freedom of Information request to Cornwall Council has revealed an extraordinary case of planning delay -a single residential application that took 1,114 days to gain approval. That’s not a typo; that’s three full years! While this is an extreme example, it is far from unique. Planning delays are nothing new, but they’re getting worse.

Across the country, developers and contractors are being forced to sit tight while local authorities work through backlogs, staff shortages, and ever-growing red tape. While we wait, the world moves on. Material and labour costs rise, client budgets shrink, and value engineering takes centre stage. The result? The steady erosion of specification quality, the abandonment of British-made products, and the growing dominance of cheaper, imported materials that often compromise on durability, sustainability, and long-term performance.

1,100 Days and Counting

According to local reports, the Cornwall case represents one of the most egregious examples of planning inefficiency in the UK. But it’s not a one-off. Across England, statutory targets of 8 to 13 weeks are now more often missed than met. Some councils have average wait times of 40–50 weeks for major applications. When planning approvals drag on for years, a project’s commercial viability is often the first thing to suffer. Prices calculated at feasibility stage no longer hold water by the time shovels are in the ground. According to BCIS, construction costs are expected to rise a further 12–18% by 2030. Labour shortages, inflation, and fuel costs are driving prices higher every quarter. That’s bad news for clients, and it’s even worse news for the UK’s manufacturing sector.

Value Engineering: When the Budget Wins and Quality Loses

With protracted planning delays inflating project costs, contractors and specifiers are increasingly being asked to revisit materials and systems. Every line item is now a target. That premium rooflight? That solid oak floor? That UK-made heritage brick? All are up for replacement.British manufacturers, once the default choice for quality-conscious clients, are being swapped out for lower-cost, and often overseas alternatives that promise 'the same look' at a fraction of the price.

But as many contractors will attest, these substitutions often come with hidden costs: which can include reduced lifespan, increased warranty claims or contravening planning approval. One example of the pressures facing UK manufacturers can be seen in the conservation rooflight market. Specialist producers, who manufacture bespoke rooflights in the UK using durable materials such as 316L stainless steel and sustainably sourced hardwood, design their products specifically to meet the strict requirements of heritage projects and to blend seamlessly with traditional architecture.

Yet these high-quality solutions are increasingly being replaced at build stage by imported plastic or aluminium products that claim to be a suitable alternative but actually fall short on appearance and longevity. In some cases, this occurs even where planning conditions call for a traditional aesthetic, as cost pressures prompt substitutions. Worryingly, such changes are being approved or overlooked more often, even under the supervision of conservation officers. The result is a gradual erosion of the very principles that conservation policy is meant to uphold, ensuring heritage buildings are restored or maintained with materials that protect their integrity, character, and long-term resilience.

The Hidden Cost of Cheap

The long-term consequences of this shift are manifold. For one, heritage projects risk being compromised by inappropriate materials that don’t weather well, don’t match existing architecture, and don’t stand the test of time. Many of these substitute rooflights, have less resistance to corrosion - especially in coastal locations where 316L stainless steel would have offered decades of resilience.

Secondly, the loss of specification quality is impacting the UK manufacturing sector at scale. Every time a British-made product is swapped for an imported one,it chips away at jobs, skills, and investment in domestic capability. Companies who make the effort to design, manufacture, and assemble entirely in the UK, are often being priced out not because our products are too expensive, but because the system is forcing clients to make impossible choices.

And finally, these changes are undermining sustainability goals. British-made products travel fewer miles, often use more responsibly sourced materials, and can be supported and serviced locally. Yet in the scramble to save money and meet tight deadlines, these benefits are too often overlooked.

A System in Crisis

At the heart of the issue is a planning system that simply isn’t fit for purpose. Local authorities lack the resources to process applications in good time. Developers are forced into multiple design iterations to meet shifting guidance. And even when permission is granted, it may come too late for a project to proceed under its original budget. Earlier this year, the Government announced an increase in planning fees - ostensibly to help councils recruit and train more planning officers. But the benefits of that investment are still years away. Meanwhile, contractors on the ground are left trying to reconcile spiralling costs with clients who are out of cash and out of patience.

What Needs to Change?

If we’re to avoid long-term damage to our built environment and to British industry, the system needs reform, and fast. Starting with streamlining and digitising planning applications, particularly for smaller or heritage-sensitive projects, would ease pressure on already overstretched planning authorities and significantly reduce the time taken to gain approval. A more efficient process would not only benefit applicants but also free up resources within local authorities to focus on more complex cases.Clearer and more consistent national guidance on materials is also essential.

Where conservation rules apply, traditional or like-for-like materials should be enforced without compromise. Allowing clients to switch to inappropriate alternatives undermines the very purpose of conservation policy, risking the loss of heritage character and setting poor precedents for future developments. Supporting British manufacturing should be a priority for all parties involved in the planning and building process. Encouraging, or even requiring, local authorities, architects, and clients to specify British-made products wherever practical not only safeguards jobs but also ensures higher standards of compliance and quality. It is also a forward-looking approach that helps to protect the long-term integrity and sustainability of buildings. Finally, better education for both clients and builders is vital.

Many substitutions are made with the best of intentions but without full understanding of the consequences. Providing clearer information on the long-term implications of cutting corners could help avoid expensive remedial works, regulatory breaches, and the gradual erosion of our built heritage.

Quality Shouldn’t Be the First Casualty

When planning takes years, and budgets balloon by the month, it's tempting to slash specifications to make the numbers work. But in doing so, we risk building homes and public spaces that fall short of both their potential and their obligations, architecturally, environmentally, and economically.

British manufacturers don’t just make products - they contribute to our heritage, our economy, and our reputation for excellence. If we want to preserve those values, we must tackle the systemic delays that are driving the industry toward the lowest common denominator. Because once you lose a manufacturer, you rarely get them back.

If you’re a developer, builder, or architect grappling with rising costs and material substitutions, consider the long view. The cheapest option today may not be the best investment for tomorrow. If you'd like to find out more about quality British made conservation rooflights for your project, please contact the Stella Rooflight team on 01794 745445 or email info@stellarooflight.co.uk    www.stellarooflight.co.uk