Traditional timber sash windows

Sash windows are a traditional type of window that became popular in Georgian architecture, and continued to be popular through the Victorian and Edwardian eras. Their elegant, timeless design means they continue to be popular in the present day. With this continued demand comes more questions about what sash windows actually are and how they work, which is why we’ve created this comprehensive guide to help you understand the varieties of sash windows available.


What are sash windows?

Sash windows (sometimes commonly referred to as ‘box sash’ or ‘vertical sliding sash windows’) consist of two separate sashes which are designed to slide up and down vertically within the window frame, rather than opening outwards or inwards on a hinge.
Sash windows can be opened by sliding from the top, bottom, or both. It is worth noting that sash windows can also open horizontally (known as Yorkshire windows), but traditionally most operate vertically.

They are traditionally made of timber, as that was the material sash windows were made of in the Georgian, Victorian and Edwardian eras. The glazed area (the sash) is made up of one or more panes of glass, depending on the era the property was built. When a sash is made of more than one pane of glass, the panes are joined together with timber glazing bars.


What are the different types of sash windows?

Sash windows must be chosen carefully so that they’re fitted according to the historical period in which they were made.

French sash windows date back all the way to the 13th century, whilst British sash windows can be dated to the 17th century.

There are several different styles of sash windows, but the key eras are Georgian, Edwardian and Victorian.

Glass was hand blown in the Georgian era so sash windows were typically made of six small panes of glass joined together in a grid of thin timber glazing bars.

By the Victorian era, plate glass manufacturing meant that panes of glass could be larger, so sash windows with two panes of glass joined with a single vertical glazing bar, or one pane of glass with no glazing bars at all became more common. We also started to see more variety in size and shape, with arched and curved sash windows being introduced.

The Edwardian era is known for decorative windows, with intricate glazing bars and even stained glass in some sash windows. A typical configuration in the Edwardian era is ‘six over two’ – with the top sash being separated into six panes, and the bottom into two.

Any good quality window restoration company (like Timbawood), will be able to know the exact style of your sash windows and will install them accordingly. For example, you wouldn’t fit an Edwardian property with Georgian sash windows as it wouldn’t look right or function properly.

In recent years more modern sash windows have developed, however here at Timbawood we focus on the restoration and upkeep of beautiful, historic buildings, using only the finest timber in the traditional way.

Wood is very durable and an excellent insulator. If taken care of properly it can last longer than the modern uPVC varieties. With the use of modern finishes, timber windows don’t have to be high maintenance.


How do sash windows work?

A traditional sliding sash window is typically made of two sashes that can slide up and down, or side to side. Both sashes are fitted in vertical grooves and are counterbalanced by weights concealed within the frame.

This weight connects to the opened sash through a cord that runs over a pulley at the top of the window frame. This method is a simple cord, weight, and pulley mechanism. Because the weights are perfectly balanced with the sashes, the sashes are very easy to move and also stay in place when opened.

Some modern sash windows use spring balances rather than the traditional pulley system.

The user-friendly design of sash windows means they are not only easy to operate but also provides excellent ventilation control. When properly cared for, sash windows can last for generations providing both timeless charm and functionality.


What are the benefits of sash windows?

Traditional and charming

Sash windows have stood the test of time for being both elegant and charming, and look beautiful from both the inside and outside of a property. They were particularly popular in the Georgian era due to their elegant proportions and symmetry.
Sash windows have been used to date period properties for years with each era having distinctive features and attributes.

Improved ventilation

Having air flow at both the top and the bottom of the window at the same time creates a ‘convection current’ of air, with the air moving in a circular motion, and cooler air being pulled in at the bottom, and hotter air leaving from the top. This is a fantastic design for ventilating a room with fresh air.

Protection from the elements

The specific design of sash windows means that they don’t slam shut with big gusts of wind. On top of this, the shape also ensures that rainwater flows away from the window rather than accumulate in the frame. This protects the wood from rotting and ensures your windows are long-lasting and remain durable.

Restore listed buildings

Most modern day windows aren’t designed to look good in period properties and listed buildings.

British architecture is such an integral part of the nation’s history that sets it apart from much of the world. Sash windows are beautiful examples of the classic architecture Britain has witnessed throughout history, and deserve to be properly maintained and preserved for as long as possible.

Sash windows fit perfectly into these period properties and allow us to keep this rich part of our culture and history alive.

Increased security and insulation

Modern advancements have meant that sash windows offer excellent performance in terms of security, insulation and durability.

At Timbawood we use stable, durable timbers such as Accoya which doesn’t swell or warp, and high security hardware such as high security fasteners, locks and restrictors to keep your home protected and you safe.

We also use full perimeter draught-proofing and high performance single and slimline double glazing to optimise both sound and thermal insulation, while retaining the authentic period design.


Why Timbawood?

At Timbawood we specialise in the sensitive replacement and repair of traditional sash windows for period properties. Our range of timber sash windows can be designed to complement any property type, from modern to period, to Listed or Conservation. As well as full replacement sash windows, we also offer sashes fitted to the existing frames, as well as sash window refurbishment, to preserve as much of the original architecture as possible.

By offering a wide range of the finest timbers, all handmade in London, in addition to glazing and hardware, you have the ability to customise your sash windows to suit your property’s style. From acoustic glass to restoration glass, traditional or contemporary hardware and a wide range of colours, stains and finishes, the options really are endless.

On top of all this, we make our heritage windows to order in our West London workshop. From designing and manufacturing to installation, you can ensure that you really are getting the most bespoke service.

If you’re looking to restore your sash windows to their original design and quality, please get in touch on 020 8038 7688 to arrange a free survey, quotation, or to visit our London workshop to see the quality of our windows being made for yourself. We work throughout London, Surrey, Middlesex and the South East.