Flush Casement Windows & Non-Flush Windows – What’s The Difference?

Flush Casement Windows & Non-Flush Windows – What’s The Difference?

Most window buyers wouldn’t know the distinction between flush casement windows and non-flush casement windows, and we wouldn’t expect them to.

We sell both solutions at Clearview Home Improvements, so we’re well qualified to tell you about them both.

The ‘flush’ refers to the flush finish on the outside of a casement window, created when its window sashes sit perfectly against the window frame.

A non-flush casement window has window sashes that aren’t level with the frame and slightly overlap it.

Get a side-on view of flush and non-flush casement designs to view this distinction, and here’s some extra helpful info.

When were the first flush and non-flush casements made?

The 19th century is when flush casement windows came on the scene, so they’re over 200 years old. Timber would be used to build them, so that’s why lots of late Georgian, Victorian and Edwardian homes have timber-built flush windows.

Non-flush windows are the older of the two as they date back to the 18th century and are still to this day the country’s most popular window style. Blacksmiths would make them as they had an iron profile, not timber UPVC or aluminium like nowadays.

A set of casement windows

Why are flush windows in fashion again?

Their revival has been sparked by the rolling out of flush windows such as Envisage, our exclusive collection, which replicates the lines and proportions of a traditional flush casement window.

Manufactured from UPVC to make it easy-care, Envisage was developed as we identified a growth market for windows that can make a house stand out from the crowd and have a different aesthetic.

A close-up of a flush casement window frame

Should I buy flush or non-flush windows?

Planners look favourably on flush UPVC windows for homes in conservation areas and listed buildings because of how closely aligned they are to the styling of original flush casements.

Flush sash windows also have a beautiful symmetry to them that’s perfect for contemporary properties – you will see lots of them finished in Black and Anthracite Grey.

The versatility of a standard casement window makes it suitable for just about any home, new or old.

An oak effect flush casement window

An advisor can politely and knowledgeably explain flush and non-flush casement windows in more detail in your local showroom. Make a date to see us.


Our made-to-measure windows and doors have the potential to change your home not just on the outside, but the inside too. From the very latest energy saving windows in maintenance free UPVC to a host of replacement doors – all guaranteed to fit perfectly with your home.


Make your home warmer, quieter and more secure by fitting our very latest energy efficient replacement windows.



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