The history of sash windows

A sash window is made of one or more movable panels, or “sashes” within a frame.  The term “sash window” is used interchangeably with the term “box sash window” in the UK, however here in Australia the term double-hung sash window is used more commonly and refers to the same type of window with two sashes that can move up and down in the window frame.

No one knows for sure who invented this time proven great design, or precisely when. But looking back over the evolution of the sash window is a fascinating journey through history. 

General consensus amongst historians is that they most probably originated in Holland or France (due to the origin of the name “sash” which means “chassis”, or frame in French) during the 17th century, and from there spread to the UK.  Some people consider Robert Hooke, an English scientist and architect, as being the inventor of these windows. In their view, this London surveyor came up with the design of these windows during the rebuilding of London after the Great Fire of 1666.

The earliest windows were not nearly as sophisticated as the later designs, often held open with poles and braces. In 16th Century Britain, glazing remained the preserve of the establishment. Glass was imported, and expensive. High-status buildings like castles, churches and palaces were glazed but the majority of dwellings would use oiled cloth, paper or thin sheets of bone, which were nailed in place.

By the late 16th century the  glazed, horizontal sash, recognisable today, began to appear. But they still had no elegant weighting counterbalance systems. Simply a frame and sash. The top sash was often fixed as originally it was thought only one opener required and this is where the name “hung sash window” emerged. Later when weights and counterbalance introduced, the term “double hung sash window” invented with both sashes being functional.

The pioneers of Georgian architecture later fully embraced the sash window movement, even adding to the design by changing the fixed top to the more modern two moveable sashes. By the mid Georgian era new, counterbalanced and thinner sashes spread and advances in glassmaking drove down prices in this period.  By 1800, even modest dwellings featured sash windows. Baltic Pine helped reduce costs further. Baltic pine is a dependable, long-lasting timber. Glass making improved and panes became larger in size, with the Georgian style of six by six panes becoming popular.

Wooden sash windows soon became the fashion du jour, and the trend swept across Britain, their popularity flourishing until the 20th century, partly due to their practicality but also due to their aesthetic appeal.

Whilst the sash window has it’s origins firmly rooted in Europe these windows are commonly found in older buildings in warmer climates, as they promote airflow and are easy to clean. A significant advantage of double-hung windows is that they provide efficient cooling of interiors during warm weather. Opening both the top and bottom of a sash window by equal amounts allows warm air at the top of the room to escape, thus drawing relatively cool air from outside into the room through the bottom opening. These windows serve to facilitate the even flow of air throughout the house and so this is ideal for the Australian climate.

During the Victorian period in Australia the sash window was taken to a new level in craftsmanship, focussing heavily on elaborate details, incorporating decorative features such as horns, latticework and mouldings into the structures. Bays started to feature ornate stone reveals and the size of panes graduated upwards from bottom to top – allowing more light in.  There are some beautiful examples of these all over Sydney and Melbourne.

During the Federation years sash windows from that period can be seen all over Australia, and have withstood the test of time. There are still thousands of  houses full of beautiful Federation Double hung sash windows of varying styles and glass types, all built by the quality craftsmen.  These window were built to last.

Sash windows have perservered over 500 years.  Many examples survive today.  Their design works in the modern day as it did centuries ago. They suit older style, heritage buildings but also look fantastic in more modern and contemporary homes including beachside and country properties.

We are excited to see so many people choosing to restore their sash windows and bring them back to their former glory!


COP26 and Draught Proofing

With COP26 (26th UN Climate Conference of Parties) currently in full swing, there has never been more focus on what needs to be done to tackle climate change. 

Whilst it is absolutely crucial that changes are needed at Governmental level,  many of us are asking what we can do in our own daily lives to make a real difference.

According to UN Environment’s latest Emissions Gap Report, lifestyle emissions in wealthy countries will have to be cut to 2-2.5 tonnes of CO2 per person to limit global warming to 1.5 degrees Celsius.

About 20% of Australia’s carbon footprint comes from household emissions.  If every Australian could cut that in half, that’s reducing Australia’s footprint by a significant amount.  A growing section of the Australian community are taking climate change into their own hands.  This includes making changes such as eating less red meat, moving superannuation into ethical funds that do not invest in fossil fuels, installing solar panels and heat pumps, and driving and flying less.

One of the most effective ways of cutting your home’s emissions is to draught proof.   Draught proofing is one of the cheapest and most effective ways to save energy – and money – in any type of building.

Controlled ventilation helps reduce condensation and damp, by letting in fresh air when needed.  However, draughts are uncontrolled: they let in too much cold (or hot) air and waste too much heat (or cold if an airconditioned building).

Draughts happen where there are unwanted gaps in the construction of your home, and where openings are left uncovered.  You should block most of these.  Windows are one of the main areas you will find a draughts and whilst foam strips work well on some windows, for sliding double hung sash windows foam strips do not work well.  It’s best to fit brush seals designed specifically for those types of windows.  Previously it has been recommended to leave this job to the professionals, but now with some basic DIY skills you can do it yourself,  and that’s where Ecobead comes in.

Draught proofing your windows will drastically reduce your energy bills and whether you live in the cold areas of Victoria or the stifling hot areas further north,  draught proofing will make your home much more comfortable.  And, importantly, helps towards the future of our planet.


Sash Window Balance Systems

For a vertical sliding sash to stay in the open position some form of counterbalance system is needed to offset the weight of the sash.  Most double hung sash windows in Australia use one of the two most viable options; Spring / Spiral Balance System or Weight and Pully System.   When installing Ecobead Parting Bead, the bottom sash will need to be removed in order to get access to the parting bead.  In this blog we talk through how to remove the bottom sash with each system.

Weight and Pulley System:

This is the more traditional system and relies on cast iron, or lead weights to counterbalance the weight of the sash.  The sash is attached to and suspended by lengths of sash cord.  Each sash cord then passes over a sash pulley which is fitted into the window jamb near the top of the opening.  The opposite end of each cord or chain is attached to the counterweight.  The weights are installed in a pocket, or box, built into the side of the window. When the window is correctly weighted, the sash will require little or no effort to operate and will remain open or closed as desired. 

In order to remove the bottom sash the cord needs to be untied from the bottom sash to release it, then tied off to hold the cord in place and prevent the cord from slipping back into the box.  After the Ecobead parting bead has been installed, the knot needs to be untied and the cord tied / nailed back onto the bottom sash.

Spring / Spiral Balance System:

Though the counterbalance principle is similar to the weight and pulley system, it’s achieved in a different way.  Spiral balances are composed of a spiral rod and spring within a metal or plastic tube.  The rod connects to the spring, which is what provides tension for supporting the sash.  The balance is held in place with a single screw at the top corner of the jamb and one or 2 screws on the bottom sash.  Each sash should have 2 balances (one on each side) to support it properly. 

In order to remove the bottom sash, the spiral balance needs to be unscrewed from the bottom sash.  Care should be taken here as the balance is under tension therefore when unscrewed the balance might spin dramatically to remove the tension. After the Ecobead parting bead has been installed, simply screw the spiral balance back to the bottom sash.