Conservation and Heritage Windows
Crafted for Conservation Projects
Derwen Joinery specialises in crafting bespoke timber windows for listed buildings and conservation properties. Our expertise has been shaped through years of close collaboration with architects, conservation officers and building contractors on projects ranging from sensitive single‑window replacements to large‑scale heritage restorations.
Our timber windows are designed to faithfully reflect the architectural character of period properties. Each piece is tailored to suit the specific building style, project requirements and any planning considerations, ensuring a sympathetic and authentic result.
Over time, we have developed a strong understanding of the planning process for listed and conservation‑area properties. While planning approval can never be guaranteed, we provide clear guidance, detailed drawings and all the supporting information needed to give your application the best possible chance of success.
Have a Project in Mind? Let’s Talk.
At Derwen Joinery, we believe every exceptional piece begins not with timber, but with a conversation. We are genuinely interested in your ideas, your questions, and the unique details that will make your project a perfect fit for your space. Understanding your vision is the most crucial part of our craft. Get in touch with us today to discuss your plans and let’s begin the journey of bringing them to life.
Material and Finish Specifications
Many of our windows can be finished using our in‑house, high‑performance three‑coat spray system, should you choose this option. Each selected component is fully end‑grain sealed and can be finished in any RAL or translucent colour, with dual‑colour combinations available to suit both interior and exterior design schemes.
For added convenience and reassurance, customers can also opt for factory‑fitted glazing and high‑specification locks and ironmongery from leading hardware manufacturers. These premium components ensure smooth, secure and reliable operation, enhancing long‑term performance.
As energy prices continue to rise, more homeowners are seeking higher‑performing, energy‑efficient glazing – particularly in older properties. To support this, we offer a range of advanced glazing options including Vacuum Insulated Glass (VIG), 12mm heritage units and 24mm double‑glazed units (DGU).
Preserving Heritage with Modern Performance
Conservation windows are designed to preserve the architectural integrity of a property while delivering the benefits of modern performance. They are well suited to a wide range of buildings where traditional aesthetics and regulatory compliance are essential.
For homeowners looking to replace ageing or failing windows, conservation‑style designs offer an ideal solution. These windows maintain the classic appearance of the original frames while incorporating modern glazing, improved insulation and enhanced weather protection. The result is greater comfort and energy efficiency without compromising the historic character of the property.
Derwen Joinery offers a variety of glazing options to meet conservation requirements, including heritage putty pointing – a traditional detail still widely specified by conservation officers and often essential for maintaining authenticity in period window designs.
Frequently Asked Questions (FAQ)
What are conservation windows and doors?
Conservation windows and doors are specifically designed to replicate the appearance and function of original features found in period properties, listed buildings and homes within conservation areas.
At Derwen Joinery, we craft bespoke timber windows and doors that respect the architectural heritage of your property, combining traditional design with modern performance. Every detail, from mouldings to glazing bars are carefully recreated to ensure authenticity and compliance with conservation standards.
Can I replace windows and doors in a listed building?
Yes, but you’ll need Listed Building Consent from your local authority before starting any work. Even like-for-like replacements usually require approval, as any alteration that affects the property’s character or appearance is regulated under heritage laws.
Do I need permission for new timber windows or doors in a conservation area?
In most cases, yes. If your property is in a conservation area or is listed, you’ll need permission for any change that alters the external appearance of your home. Our team can assist by providing technical drawings and detailed specifications to support your application.
How can I make sure my new windows and doors meet conservation requirements?
Your replacement products must match the originals in style, proportions, materials and detailing. This includes replicating features such as:
Glazing bar patterns and moulding profiles
Opening styles (e.g. sash, casement, or panelled doors)
Traditional ironmongery and finishes
Derwen Joinery ensures every timber window and door is made bespoke to your building’s exact requirements.
Are your windows and doors approved by conservation officers?
All our timber windows and doors are crafted to comply with local conservation guidelines. We supply full CAD drawings, detailed specifications and heritage glazing options to support your Listed Building Consent application.
Why is timber the preferred material for listed and heritage properties?
Timber remains the preferred material for heritage buildings, as it faithfully replicates traditional craftsmanship and detailing.
Our timber products deliver:
Authenticity – Accurate period profiles and traditional joinery
Longevity – Superior strength and stability
Sustainability – Responsibly sourced materials
Planning approval confidence – Trusted by heritage officers and more likely to meet conservation requirements
How does the listed building consent process work for windows and doors?
Consult early with your local planning authority or conservation officer.
Document existing features with photos and measurements.
Submit your application including detailed designs, materials and justification for replacement.
Our team can provide all necessary technical documents and heritage detailing to support a smooth approval process.
What are common mistakes to avoid with heritage window and door replacements?
Starting work without Listed Building Consent
Using uPVC, composite or aluminium instead of timber
Failing to match historic details like mouldings or proportions
Ignoring heritage glazing rules
Working with Derwen Joinery ensures your project meets every conservation and performance standard.
Can my new conservation or heritage windows and doors have double glazed units?
Depends, each project will have varying requirements dependent on status and location. But yes, vacuum glass (VIG), 12mm heritage and 24mm DGU have been approved for manufacture. Rising energy prices have increased demand for higher-performing, energy-efficient windows especially in older properties and this is considered by conservation officers.
Can my windows have plant on glazing bars?
This will entirely depend on the conservation status, historic value and conservation officers requirements.
In heritage projects specifying vacuum glass, the use of a single, energy-efficient unit makes the incorporation of plant on glazing bars the most effective solution.
Check out our blog!
Our New CNC Machine at Derwen Joinery
Our New CNC Machine at Derwen Joinery At Derwen Joinery, we are always looking for ways to improve the quality, accuracy, and efficiency of our work. In December, we took an exciting step forward...
High-Performance Timber Windows and Doors with PassivGlas™
High-Performance Timber Windows and Doors with PassivGlas™ We’re proud to offer PassivGlas™, a premium glazing system that delivers the perfect balance of performance, sustainability, and design...
Another successful BM Trada Annual Fire Door Audit for Derwen Joinery
Success for Derwen Derwen Joinery has once again passed the rigorous BM TRADA Fire Door Audit, reinforcing our commitment to fire safety and regulatory compliance. This annual audit, conducted by...