High security meets traditional design

The Sash Secure 240 is a hybrid window product, combining the highest levels of security with the elegance of a traditional timber design.
Unlike most security windows which offer a more basic aesthetic, the Sash Secure 240 will blend well with existing or neighbouring traditional windows, meaning customers don’t need to compromise on design or safety.

Product Features

Key design elements

What is it that sets the Sash Secure 240 apart from other secure or traditional windows?

Key elements of aesthetic design, security and performance combine to offer the best in traditional windows with the added bonus of security to the highest standard.

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Subject to 16 of the highest standard tests, the product survived 240 minutes of attack. Features include an integrated glazing unit to prevent removal and steel reinforcing devices. There is also the option to have the unit chemically fixed to the building fabric, preventing bomb blasts from blowing in the window.


Thanks to a bespoke glazing bar, the Sash Secure 240 has been specially designed to mimic traditional windows. This clever addition means that the product is able to meet the design standards specified by London Authorities.


Sash Secure 240 is a fully operational, traditional sash window featuring the usual weights and cords. In terms of thermal efficiency, U-values range from 1.3 double glazed, to 5.0 single glazed, meeting building standard requirements. The product is draught-proofed to BS 6375 part 1, and adding acoustic glass can reduce sound levels.

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

Bespoke secure heritage windows made to order

At Sash Window Conservation, our team is with you every step of the way. We will ensure that every option is explored so that your bespoke order offers you the very best solution not only in terms of style, but also in terms of cost.

You can rest assured that all of our designs will comply with the requirements of local authorities, thanks to their heritage style and easy installation, including the Sash Secure 240. Created in our Kent based factory, we are able to accommodate almost any order, so long as it is based on a heritage design.

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Security and design of equal importance

Our Sash Secure 240 product has been specifically designed to offer our customers the highest level of security, whilst never compromising on heritage design. Each bespoke product will be made with your project’s individual requirements in mind, and will be subject to high intensity testing to ensure maximum security has been achieved.

The aesthetic appearance of the Sash Secure 240 will ensure that it complements any existing or neighbouring windows, whilst simultaneously offering the highest level of security for your project.

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Drilling into a timber frame

Case Studies

See how our bespoke heritage products have enhanced previous projects with testimonials from our valued customers below.

Who we’ve worked with