The passage of time has proven the Double Hung Sash Windows to be an excellent design. The working life span can be measured in hundred of years. Sash Windows are now having a revival in popularity, leading to many manufacturers exploiting this highly profitable market.

Most modern Sash Windows have a different set of criteria on the design from the traditional designs. The demands on a modern window have a negative effect on the performance that made the traditional sash windows so successful in the past.

Criteria of maximising profitability and complying with current regulations overpower the simplicity of the original design. Adding complexity complicates the long term maintenance. If in twenty to thirty years time replacement components aren’t available the window will have to be scrapped. Original two hundred year old window can still be maintained and repaired to this day. The same can not be said for plastic windows installed only 20 years ago.

Influences on a design, throughout it’s history, have to be understood before any re-design can be successful. Without this analysis and comprehension, a designer can not make the right choices to retain the original winning features and benefits..

The design of Double Hung Sash Windows evolved over time. Each stage in the Sash Window history has been tried, and proved. Changes in glazing technology have driven many of the variations to the basic design. These changes where successful incorporated in design. Any failures won’t have survied to the present day.

The requirement to install sealed unit double glazing is the biggest challenge to the traditional sash window. Many modern manufacturers have chosen to ignore or are ignorant of problems that this new glazing imposes to the design. As a result, customers will be disappointed a few years down the line when they have to pay for expensive remedial work. Even more dismayed when the specialist components are no long available.

A few manufacturers have made a good attempt to incorporate double glazing in to Sash window designs. Some have taken existing solutions from modern timber window design and applied them directly to Sash Windows. These windows should perform well over many years and they retain the ability to be repaired. Unfortunately the technology for glazing these windows is adapted from casement style windows where the frame design is fairly heavy in appearance.

Most modern Sash Window with double glazing don’t have the aesthetic elegance of a traditional design. The details also highlight the modern construction. If we are making windows that comply with the modern demands of energy conservation, we have to make some changes to the aesthetics. New double hung window designs should be see in the light of past changes in design, driven by the latest glazing technologies. Modern windows don’t have to be replicas but they do need to be honest.

When judging a new design, we should ask:

a) Do the design detail detract from what we are expecting to see?

a) Is the design sympathetic with the build style and proportions?

c) Is the design detailed to maximise longevity?

d) Will future maintenance and repair be possible and straight forward?

These questions need answering in a historical context. Thecontinuity of a successful, evolving design will help to ensure modern windows have the best chance of lasting hundreds of year. Good designs should perform to modern standards and survive.

The initial step of a project to design and build high performance double glazed, double hung sliding sash windows, should be a look at the historical background. This has been my starting point as I’ve been developing a design for sash windows that I can build myself.

Going down this route will give me windows that will perform and out-last me. The cost per unit will be lower than equivalent uPVC alternatives, the value of the house will be raised and energy bills lower. The plans will be valuable source of information for anyone with some basic skills and a desire join generations of craftsmen constructing, sustainable architectural joinery.

Author Bio: Andy Bell is a designer exploring the application of modern technological advances to traditional craft based designs. The resulting plans can be built using basic woodworking tools and only require a moderate skill level. The History of Double Hung Sash Windows and project progress are on his iDoStuff website

Category: Arts and Crafts
Keywords: sash windows, double hung windows, box sash, history, designs, plans, first