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Conservation and Heritage Windows

Timber Windows Crafted for Conservation Projects

Derwen Joinery specialises in handcrafting bespoke timber windows for listed buildings and conservation properties. Our extensive experience comes from collaborating with architects, conservation officers and building contractors on projects ranging from minor replacements to major renovations of heritage properties.

Our timber windows faithfully replicate the architectural style and character of period properties. We tailor each window to suit your property type, project requirements and any necessary planning approvals.

We have developed a deep understanding of the planning approval process for listed and conservation properties. While planning approval can never be guaranteed, we provide you with all the necessary tools and guidance to maximise your chances 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.

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Material and Finish Specifications

With the application of our in-house, high-performance three-coat spray system, each window and component is end-grain sealed and finished in any RAL or translucent colour, with dual-colour options available.

For convenience and peace of mind all windows are supplied with factory-fitted glazing and high-specification locks and ironmongery sourced from leading names in the hardware industry which will ensure smooth, secure and effortless operation, enhancing longevity and reliable performance.

Rising energy prices have increased demand for higher-performing, energy-efficient windows especially in older properties paving the way for Vacuum glass (VIG), 12mm heritage and 24mm DGU.

Preserving Heritage with Modern Performance

Conservation windows are designed to preserve architectural integrity while delivering modern performance. Their applications span a range of property types where traditional design and regulatory compliance are key.

Homeowners looking to upgrade old or failing windows can benefit from conservation-style replacements. These windows maintain a classic appearance but incorporate modern glazing, improved insulation and enhanced weatherproofing, delivering greater energy efficiency and comfort without altering the property’s historic appeal.

Derwen Joinery provides a variety of glass and glazing options including the use of heritage putty pointing, which continues to feature in today’s traditionally improved window designs and is often specified by conservation officers.

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?

  1. Consult early with your local planning authority or conservation officer.

  2. Document existing features with photos and measurements.

  3. 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.

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