Sash windows are a technically superior and stylish feature of old buildings that should be retained, says Dermot Cooke – saving you cash and even making you money on your developments

Traditional sliding sash windows are a design classic. Though it’s 300 years since they were first introduced, they are still associated with simple and functional style.

The subtle proportions and technical elegance of the sash led many of Britain’s finest architects to use them as a visual calling card for their talents. Georgians loved their mathematical proportions, and Sir Christopher Wren put their aesthetic appeal to good use in his designs for Kensington Palace: after all, the new window could be opened without spoiling the façade.

Royal patronage led to examples appearing at Chatsworth House and Hampton Court Palace, and Victorian architects wholeheartedly embraced them, making sash windows a central focus for buildings – grouped in impressive bays and lavished with ornamentation.

As early forms of air-conditioning, sashes were designed to provide effective ventilation by allowing heat to escape through the top window, and cooler air to enter through the bottom. The window’s design adapted over the centuries in line with technology, from the multi pane arrangement of the 17th century (when glass was at its most expensive); to the larger, lightweight panes and thin glazing bars of the Regency period, and the single plate glass panes of the 19th century.

Sash windows of the 18th and 19th centuries demonstrate extremely fine examples of joinery, while robust and skilled craftsmanship – such as the ‘bulls eyes’ in the hand-blown crown glass panes – mean they have stood the test of time (1950s demolitions aside).

Stick with the sash
When embarking on a building or renovation project on an old property it certainly pays to keep the original sashes, not least because they play a vital part in the heritage of British architecture – each is an antique in its own right.

English Heritage’s Chief Executive Dr Simon Thurley has warned that Britain’s most historic areas are being spoilt by a “plague of plastic windows”, and estimates that more than four in five of the country’s 9,300 conservation areas are affected by an influx of PVC.

Each year, tens of thousands of sash windows are lost.  This is despite the fact they were originally designed to last for centuries, be regularly serviced and repaired and, with specialist care, can deliver a 21st century performance.

 “Windows and doors that are original make a major contribution to the character of traditional houses,” says English Heritage. “They should not be altered as they are conspicuous elements of the design.”

Douglas Kent, Technical Secretary for the Society for the Protection of Ancient Buildings (SPAB), agrees: “Old windows contribute immeasurably to the special interest of a building, and the timber used historically is superior to that widely available today.”

Furthermore, it’s possible to save significant sums of money on a development by getting in a specialist to renovate a sash window rather than replace it. All 15 elements that make up the window can be repaired and this is by far the most cost-effective option; replacement windows can cost many times as much.

The main problem associated with old sash windows is that they can develop gaps that allow air to leak around the perimeter, which causes draughts and allows heat to be lost. The latest renovation technology makes it possible to hide a brush pile system within the sash’s timber beading, virtually eradicating draughts, rattles and pollution, and enabling smooth, safe and near-silent movement – without changing the appearance of the window.

Renovating sash windows can go a long way to reducing the carbon footprint of a building project. Timber-frames offer environmental benefits over man-made materials and most of the original materials can be re-used; as little as half a bag of rubbish is generated when renovating a window.  What’s more, PVC only has an average life expectancy of 18 years.

Cash clever
Figures from property experts suggest it’s possible to make more money on developments by retaining sash windows, because homebuyers favour original features.

In a recent survey undertaken by estate agents Knight, Frank and Rutley, 10 factors were identified which make properties difficult to sell – the two major ones being the loss of original features and the fitting of replacement windows.

Phillip Davies, a regional planner with English Heritage, suggests that period authenticity can add between 5 and 15 per cent to the value of a house.

“Inappropriate replacement windows blight old buildings. They are the home ‘improvement’ likely to cause most harm to a property’s value,” says SPAB’s Douglas Kent.

Dermot Cooke is a qualified joiner; sash window expert and founder of sash window renovation specialist company Sliding Sash Solutions.

T: 0800 731 5905
E: d.cooke@slidingsashsolutions.co.uk
www.SlidingSashSolutions.co.uk