Sash Windows
What is a sash window?
Sash windows are the vertically-opening windows you often see on traditional buildings and architecture.
Sash windows come in a variety of different builds and styles. The most common types of sash windows are Georgian, Victorian and Edwardian windows – each varying slightly different in style and number of windowpanes.
See the different styles here:
Georgian Sash Windows
Georgian sash windows are characterized by their simple, elegant design. They typically feature six-over-six, eight-over-eight panes of glass or nine-over-nine. One of the defining features of Georgian sash windows is their attention to symmetry, with each window having an equal number of panes on each sash.

Victorian Sash Windows
Advances in glass making by the Victorian period meant that consumers could opt for larger panes of glass. As these designs typically allow more light into the property and are easier to maintain, they proved extremely popular. Victorian sash windows often featured a single, central glazing bar, which gave the windows a cleaner and more streamlined appearance compared to the multiple glazing bars used in Georgian sash windows.
Edwardian Sash Windows
The Edwardian era saw a trend towards handmade, artistic designs and Gothic-style structures, which influenced the design of sash windows. With the growth of suburbs and larger houses without servants’ quarters, Edwardian sash windows featured larger panes of glass, simpler designs, and a single, central glazing bar for easier maintenance, reflecting the era’s emphasis on functionality and showcasing the homeowners’ wealth and ample living space.
How do I know if I have sash windows?
You’ll know if you have sash windows as they are opened, closed and secured differently than conventional windows in modern housing today.
Sash windows slide vertically using pulleys, and fasteners or restrictors are used to secure the window in an open or shut position. The standard UPVC windows used in modern housing typically use a handle to push the window outwards to allow air in.
Why you should upgrade your sash windows
Many properties with sash windows have had them for some time. If this is the case, it’s likely they’ve suffered some wear and tear and could do with a repair or replacement.
Since the conception of sash windows, technology and quality have improved drastically. You could be missing out on the benefits of modernised sash windows, casements and doors.
Some of the main reasons you should look to upgrade your sash windows are:
Increased energy efficiency – If your home still has its original sash windows, they’re likely single-glazed. Higher-quality, thicker timber allows modern sash windows to have double glazing – helping to heat up your home and save you money.
Bolstered security – Older sash windows are notoriously prone to security issues – a thief that knows what they’re doing can gain access through an old sash window in no time. Modern sash windows come with additional security features and locking mechanisms as standard that outdated windows may not be equipped with.
Improved aesthetic appeal – Modern sash windows have both form and function. Timber sash windows also have a traditional, rustic feel that their plastic or aluminium counterparts can’t quite match – hence why they’re still popular.
Fully customisable – Sash windows allow you to style your windows exactly how you want them. Choosing between the number, type and arrangement of windowpanes, hardwood or softwood timber, and double or acoustic glazing means there’s an option for everyone – especially if you’re looking for a change.
Easy to maintain – As long as you nurture timber sash windows, they can remain in good condition for decades. UPVC sash windows are difficult to repair – it often involves replacing large sections of the unit rather than targeting specific areas.
That’s why at Core Sash Windows, we only specialise in the highest quality timber windows and offer a 10-year guarantee right from installation.
If modern sash windows are something you’re looking for, get an instant quote and a free in-person evaluation and measuring today or contact us to chat with a member of our team.
Get a quotation for your perfect windows
All our windows are bespoke products, so there’s no compromise on design
FAQs
Do I need planning permission to replace a sash window?
Provided you own the home, you do not need planning permission to change, replace or upgrade your sash windows, casements or doors.
If you live in rented accommodation, you’ll need permission from the landowner before undertaking renovations.
Should I replace the original sash windows?
Outdated sash windows are subject to wear and tear.
If they’re not maintained properly, moisture can cause the timber in the frames to rot and weaken. This can cause the wood to warp and buckle – causing drafts and noisy rattling.
Some of the signs your sash windows might need an upgrade are:
- Peeling paint
- Water Ingress
- Stiffness on operation
- Rattling on operation
- Self-raising or self-lowering
- Draughts or howling
- Rotten timber
- Bending, bowing or breaking of the timber
However, with proper maintenance, sash windows can remain in tip-top condition for decades with the right fitter and quality materials.
If you’ve noticed these symptoms on your windows, it might be time for an upgrade. Get an instant quote or contact us today to find out how we can help you fit your dream windows.
Get a quotation for your perfect windows
All our windows are bespoke products, so there’s no compromise on design
Are original sash windows easy to break into?
Modern sash windows are incredibly safe.
While contemporary sash windows may have been more susceptible to break-ins in the past, stronger double glazing, more durable timbers and security features – like sash window screw locks and fasteners – mean security issues are no longer a concern.
Can you double-glaze existing sash windows?
Yes, you can.
Modern sash structures can support thicker, more durable timber, offering more room for double glazing and improved insulation – should you upgrade.
How do you measure up for a sash replacement window?
Measuring your sash windows may seem complicated, but it can be done in three easy steps.
- Extend the measuring tape down the entire vertical length of the sash box and record the measurement.
- Extend the measuring tape across the horizontal width and record the result.
- Send the measurements off to us – we’ll handle the rest.
It’s crucial to remember that these measurements are only accurate for sash replacements.
If you need the sash box changed as well, add 135mm to the vertical length and 150mm to the width to cover the measurements for the additional box unit.
If you need additional assistance or are just unsure, we’ll conduct a no-obligation survey – free of charge – to give you peace of mind knowing everything’s being handled correctly.
Can you soundproof sash windows?
Yes, it is possible to soundproof sash windows.
While additional glazing reduces the sound naturally, discreet acoustic glass can be fitted for soundproofing.
Looking for new sash windows? Core Sash Windows boast an extensive range of fully-customisable windows, casements and doors to fit all specifications. Book your free measuring and evaluation by getting an instant quote and transform your home today.