Is a flush casement window more expensive?

Yes, typically a modest premium over a standard casement of the same size, reflecting the more precise manufacturing needed to maintain weathertightness without an overlapping sash lip.

Are flush casement windows less weathertight?

No, when properly manufactured and installed they perform to the same standards as standard casements. The design simply requires more careful engineering of the rebate and drainage detail, which is factored into the higher price.

Can I get flush casements in aluminium?

Yes, flush casement styling is available in both aluminium and uPVC, including the Residence Collection, so the choice of flush versus standard is independent of which frame material you choose.

Do flush casements suit modern houses?

They can, but their main appeal is replicating traditional timber joinery, so the visual benefit is most obvious on period or characterful properties. On a genuinely modern house, a standard casement or a different style entirely may suit better.

Product Comparisons

Flush Casement vs Standard Casement Windows

A flush casement sits within the frame rather than proud of it. It is a small structural difference with a real effect on how traditional or contemporary a window looks.

3 min read

Casement windows, hinged at the side and opening outward, are the most common window style in the UK, and most people picture the standard version without realising there is an alternative. A flush casement window closes so the opening sash sits level with the surrounding frame, rather than sitting proud of it, echoing genuine timber sash and casement joinery from before uPVC and aluminium existed.

Side by side

	Standard casement	Flush casement
Sash position when closed	Sits proud of the outer frame	Sits flush within the outer frame
Visual style	Practical, straightforward	Traditional, timber-like, tailored
Best suited to	Most homes, cost-conscious projects	Period properties, cottages, conservation areas
Weathering detail	Simple overlap seal	More precise rebate and drainage detailing
Typical cost	Baseline	Modest premium over standard casement
Available in aluminium and uPVC	Yes	Yes

Why choose flush

Flush casements were developed specifically to replicate the clean, level appearance of traditional painted timber windows, which sat flush within their frames long before proud-fitting sashes became the standard, cost-effective manufacturing approach. On a stone cottage, a Georgian terrace or anywhere the original joinery would have been flush, a standard casement can look subtly modern and slightly at odds with the building, even in a sympathetic colour.

The flush design requires more precise manufacturing to maintain weathertightness, since there is no overlapping lip doing the simple job of shedding water, which is why it carries a modest premium over standard casements.

Why choose standard

For the majority of homes, particularly newer builds, standard casements are perfectly appropriate, cost less, and are available in the widest range of configurations and opening styles. There is no functional or thermal disadvantage to a standard casement; the difference is purely about visual authenticity relative to a period building.

Which should you choose

Choose flush casements if your house is genuinely period in character, sits in a conservation area, or you are specifically trying to replicate the look of original timber joinery. The extra cost buys a noticeably more authentic appearance up close.

Choose standard casements for most other homes, particularly newer builds or where budget needs to stretch across many windows. Paying the flush premium on a 1990s estate house buys very little, since there is no original timber character to replicate in the first place.