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With a rich heritage stretching back hundreds of years, Britain is bursting with beautiful historical architecture. One feature in particular that has stood the test of time is the classic sash window. But what exactly is a sash window, and where is the sash?

In this post we take a closer look at the history of this iconic British feature and what components make up the sash window.

Brief history of sash windows 

Sash windows were invented by British architect Robert Hooke over 400 years ago, preceding the Great Fire of London and the English Civil War. However, the bottom sash was originally held open by props such as wooden pegs or blocks for many years before the classic rope system was introduced.

In this early period, glass was also a valuable commodity, which meant leaded lights were originally installed. As a result, sash windows had much smaller glass sections held together by small lead bars.

As glass came down in price, more grand and impressive windows were introduced in the Georgian period. The panes were much bigger and became the typical square format we all know and love today. As craftsmanship progressed, the Victorians used sheet glass. This posed new challenges as the weight of design meant chains had to be used to hold open the windows.

Once a standard window in the history of British homes, sash windows quickly became a sign of wealth and heritage. The larger the pane of glass, the wealthier a family appeared. Over time, they have become a statement of class and character on properties. Today, the durability of sash windows is second to none, with homes up and down the country featuring century-old sash windows.

What is a sash?

Despite the changes in glass and structure over the centuries, the sash of the window remains as strong as ever. Put simply, the sash is the section of the window that is moved to open and close it. It holds the pane of glass, or several panes, to create one single panel, which is fitted into the window frame. These movable panels or sashes are separated by glazing bars and moulder strips of wood.

There are various parts to consider when it comes to a working sash window. That includes the sill, top and bottom rails, sash weights, cords and timber linings. The traditional components all seamlessly work together to create a long-lasting solution, all of which add to the aesthetic appeal and functionality of the full window.

How do sash windows differ?

Sash windows have certainly stood the test of time and have become an important piece of British architecture. If you are lucky enough to have sash windows in your home, you will recognise them by identifying the era in which they were developed. To be exact, three popular styles have emerged throughout history, including:


First is the single-hung sash window, which was first introduced in the Georgian era. This features one pane of glass, which is the only moving section in the window.


The next trend of sash windows brought about the double-hung sash. This was used in Victorian and Edwardian homes. The double-hung sash window has two sections which slide up and down, which has since been incorporated in multiple sequences.

Horizontal sliding sash windows

Another type of sash window is the horizontal sliding sash window, which uses two sashes. As the name suggest, the sashes move horizontally rather than vertically.

The best of three

As with most things, sash windows have adapted and changed over time. If your sash windows don’t fit perfectly into any of the types above, they will most likely be a variation or a mixture of all three. This can include bigger panes, a different sequence of panes or a different number of glazing bars.

The benefits of sash windows

Famed for their beauty and their functionality, the benefits of sash windows are evident from their long-standing history:

Aesthetic appeal

Wooden sash windows are a beautiful feature, which look fantastic in any period home. They add oodles of character and charm, with a classic British style.

On the flipside, modern PVC windows look completely out of place in a period property or listed building. Unlike PVC, wooden sash windows add significant value to any property. If you were to sell your home, it would be more cost effective over time to repair and restore rather than replace completely.

Heat insulated

You may think older windows can’t give you the same insulation qualities of modern PVC double glazing options. However, with draught-proofing you can maintain the aesthetic appeal of sash windows with all the added thermal insulation qualities.

At Fortis & Hooke, we provide an innovative DS Perimeter Draught Sealing System. This ensures the windows are completed sealed and renovated to help deliver optimal thermal insulation.


Another key benefit of sash windows is that they offer fantastic versatility. Whether you own a period property town house or you’re the manager of a national trust listed building, there’s something to suit every style.

When making repairs and restoring damaged windows, you can add bespoke glass suited to your requirements. This includes insulated low-e glass used in double glazing, self-cleaning glass or glass which has reduced glare.

Environmentally friendly

Maintaining your original wooden window features is also a fantastic way to reduce your carbon footprint. The insulation qualities of fully draught-proofed sash windows allow you to cut down your energy bills and make your home more energy efficient. It also cuts down unnecessary waste from PVC replacements, which use significant amounts of energy and non-biodegradable materials.

Staying on top of repairs with the experts

To ensure you enjoy all the benefits of sash windows in your home, it’s crucial to make repairs where you can. This not only maintains the functionality of your windows, but helps you preserve the beauty of traditional features.

At Fortis & Hooke, we can help restore your windows to their former glory with our innovative and long-lasting repairs. If your sash windows are in need of a thorough restoration and you want to discuss your options with a specialist, contact our friendly team today on 0800 313 4688 or email info@fortishooke.co.uk.

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