Architectural Timber Windows
Flush Casement Windows
A flush casement sits flat in its frame, so the window reads as a single plane. That flat face is the whole difference between a period casement and a modern stormproof one.
The flat plane
On a flush casement the opening sash closes flush with the face of the frame, so the window reads as one continuous plane — the way a period casement was built. The alternative, the twentieth-century stormproof casement, has a rebated sash that sits proud of the frame with an overlapping lip, casting a heavy shadow line that reads instantly as modern. On a period or conservation-area property the flush detail is the correct one, with slim stiles, rails, and moulded glazing bars matched to the building.
Performance without the lip
A flush casement does not have to choose between appearance and performance. Concealed compression draught seals let into the rebate seal the window without a visible lip, and slim-profile double-glazed units in correct moulded bars add thermal performance while holding the flat sightline. Ironmongery — peg stays and casement fasteners — is specified to the period. The result performs like a modern window and reads like the original.
- Suits
- Victorian & period properties · conservation areas
- Defining detail
- Sash sits flush with the frame — a single flat plane
- Versus stormproof
- No proud lip / heavy shadow line; reads as period
- Performance
- Concealed compression seals + slim-profile DG
- Ironmongery
- Peg stays & casement fasteners, to the period
Common Questions
What is a flush casement window?
A casement window whose opening sash closes flush with the face of the frame, so the window reads as a single flat plane — the period-correct casement, as opposed to the proud, lipped stormproof casement.
Why choose a flush casement over a stormproof one?
Because the stormproof casement’s proud, lipped sash adds a heavy shadow line the original elevation never had, which reads as modern. The flush casement keeps the flat period plane.
Can a flush casement be draught-proofed and double-glazed?
Yes. Concealed compression seals in the rebate seal it without a visible lip, and slim-profile double-glazed units in moulded bars add performance while keeping the flat sightline.
Are flush casements right for a Victorian property?
For Victorian cottages, lodges, estate housing, and Arts-and-Crafts properties, yes — the flush casement is the correct period window; a sash-windowed Victorian terrace wants sashes.
Considering flush casement windows for a period or rural property? The conversation starts here.
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