Two colleagues discussing over paperwork
Handmade bespoke window being made in a bright modern 2023 factory.

Our Story

Over 20 years ago, our Managing Director Neil Berkeley recognised an industry need for a company offering a fully comprehensive service for architects and main contractors looking to solve issues with heritage windows.

His answer was to establish Sash Windows Conservation in Kent, employing a specialised team of highly skilled joiners, site staff, technical support and employed installation technicians. Our joinery shop was purchased in 2004, where the team is able to design and manufacture any window or door to order, as long as it’s traditional, followed by our own factory, which increased our manufacturing capacity by up to 40%.

Our Philosophy

At Sash Window Conservation, our philosophy is to respect our past and embrace the future. With this in mind, our long-standing staff offers our customers integrity and experience, with the promise that our team will remain with you throughout your project to ensure optimum results.

Looking ahead, our products are designed to take into account the need for increased energy efficiency and reduced maintenance, incorporating draught proofing, compliant U-values and G-values, and offering cleaning solutions with ISO 9001 quality. In 2014 we developed acoustic standard windows to BS717-12 (2013), followed by our anti-attack window – Sash Secure 240 – from 2016.

Our respect for the aesthetic and architectural integrity of preserving a building with traditional methods of working, combined with our dedication to meeting ever-changing modern standards, means that Sash Window Conservation is the perfect choice for your heritage window and door solutions.

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Our Solutions

We offer our customers a range of services that provide solutions to any heritage window or door requirements they may have. Below is some further information on the services we supply and the type of customers we usually work with.

Drilling into a timber frame

Bespoke Solutions

We can offer complete refurbishment, for original box sash and timber casement windows, together with draught proofing and a repair service. Our bespoke service includes a free project walk through survey and completed tender or bills of quantity pricing. Customers can also opt for an in-depth survey including opinions, photographs and diagrams of required repairs.

Technical drawing stock images

Comprehensive Solutions

Our own team of highly skilled craftsmen will use modern tools to carry out the work onsite, taking the same level of care and pride as the original workmen, and refurbishing the windows using traditional timber splice repairs in conjunction with Timber-Care repairs (approved by English Heritage). Options include reglazing glass for increased thermal and noise insulation. We can either carry out comprehensive refurbishment or in-house manufacture, with our new sash and casement windows and doors including easy clean.

Two colleagues discussing over paperwork

Business Solutions

We mostly work alongside architects, property developers, building contractors and local councils on their heritage projects.


At Sash Window Conservation, we are proud to have received a number of accreditations confirming the quality of our work and the dedication of our team. All of our site team have health and safety training, and work directly for us, not as sub-contractors. We are able to take on contracts valued up to £2 million, and are also members of Constructionline and Builder’s Profile.
Below are some examples.

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As a FENSA accredited supplier/manufacturer, our draught proofing system is certified to BS3675 Part I. A government-authorised scheme, FENSA ensures that replacement window and doors comply with current building regulations.

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FSC® certified

As an FSC certified company, our customers can rest assured that we are diligent with ensuring our materials are responsibly and sustainably sourced, complying with the most stringent environmental, economic and social standards.

BSI ISO 9001 Quality Management logo

ISO 9001

We have received a fully integrated and documented quality policy certified to ISO 9001 (2015), which is testament to the high level of excellence achieved with our quality management systems.

Construction Online Gold

Construction Gold

Our Constructionline Gold Membership means we are qualified above and beyond PAS 91 requirements, meet the Common Assessment Standard, pre-qualify for some of the UK’s biggest buyers, and are SSIP accredited. This means you can rest assured that you are buying quality products that meet or exceed all the necessary requirements.

Builders Profile Logo

Builder's Profile

By being registered with Builder’s Profile, the PPQ and Assessment submission process is made easier, and all information is kept fully up-to-date with a database used by all subscribers.

Our Buying Process

At Sash Window Conservation, we aim to keep the buying process as simple and straightforward as possible, giving you the peace of mind to focus on your project. Read more about how it works below.

Share your goal with us

When you contact us, we will arrange a call to run through your specification and ideas. You can then share any documents or drawings you have of your project, and what you’d like to achieve with the end result.

We will take this and see what we think is realistic and would work best for your project, timescale and budget.

We will then share our thoughts with you and see how they match up with your vision.

landscape image of university of the arts in london using traditional sash windows

We may pay you a visit

We may arrange a visit to ensure that the bespoke design or refurbishment plan that we have in mind will be just right and fit with the rest of the building and its neighbours.

We can then make any necessary adjustments and begin preparing your bespoke quote.

Canal side of Jamie Oliver HQ, Regent's Canal, King's Cross using new windows retaining the traditional sash window aesthetic

Providing your quote

Once your specification and requirements have been agreed upon, we will put together a bespoke quote. This will include a price per window so that you know exactly what you’re paying for, a range of options to ensure you choose the best solution for your needs, together with our own recommendations based on your individual project.

Our quote will also suggest ways in which you could save money, to help you to stay within your agreed budget, whilst getting maximum value from your order.

Society of Antiquaries building using traditional timber sash windows, also showing the arched entrance

Creating your bespoke design

Following your approval of our quote, we will get to work on creating your bespoke design in our Staplehurst factory.

Once our team have created a selection of samples, you will be offered the chance to visit our factory to review them before we go ahead with the final product.

university of the arts in london using traditional sash windows

Who we’ve worked with