Compare The Best Flush Casement Window Choices for Your Home

Compare The Best Flush Casement Window Choices for Your Home

What choices are available for my home’s best flush casement window? Let’s start with the term casement. This describes an opening window whose hinges attach it to its frame, allowing it to open outwards. A casement stay, a small arm with holes attached to the bottom of the opening sash, often held casement windows open by connecting to a peg in the frame. These windows typically open sideways. People refer to bottom-hinged windows as hoppers and call top-hung windows awning windows.

Flush Casement Window History

Flush casement windows began appearing in nineteenth-century Edwardian and Victorian homes. At that time, manufacturers used timber to produce them (like almost all windows then), and they competed with sliding sash windows in new houses. We call these windows “flush” because of the window’s external appearance. The opening window (when closed) sits completely flush with the external frame. Glass manufacturing capabilities (manufacturers did not produce glass on an industrial scale in large sheets) forced the use of the Georgian pane. As time moved on, advances in glazing technology and the timber industry reduced the number of casements from 6 to 2 panes per window.

Stormproof Casement Windows

We generally refer to common and more modern window designs that overlap the frame as stormproof casements. Manufacturers introduced these in the 1950s. They added a lip to the opening to prevent the window from sitting flush. This causes the window to sit proud of the frame, which people often call lipped casement windows. This modern design actually ensures extra protection against the elements, which gives it the name “stormproof.”

The Revival of Flush Windows

Flush casement windows resurged in popularity over the last few years because manufacturers developed stunning, authentic modern systems that not only look good but also provide excellent thermal properties. Increasing demand for windows with a different aesthetic than traditional casement designs also drove their renaissance. Some consumers follow trends and embrace change.

Best materials for a flush casement window

We supply and install uPVC, aluminium and timber flush casements across Andover, Hampshire and surrounding counties—each with pros and cons

uPVC (incl. Deceuninck 2800 “Heritage/Infinity”, Residence 7 & Residence 9)

• Looks: outstanding timber-effect foils, seamless/Graf welds and mechanical joints available
• Performance: A-rated double as standard; 44mm triple glazing options on select systems
• Value: best £-for-performance for most retrofits

Aluminium (Sheerline, Smarts Alitherm 400 flush)

• Looks: ultra-slim, crisp sightlines; modern palettes
• Performance: high-spec thermal breaks; double or market-leading 44mm triple on certain ranges
• Best for: contemporary projects and large formats

Timber (George Barnsdale; engineered softwood, hardwood, Accoya)

• Looks: the real thing; ideal for sensitive properties
• Care: lowest U-values with proper specs; periodic finishing required
• Best for: listed buildings (subject to consent) and authentic restorations

Conservation & listed buildings: quick guidance

• Listed buildings: you’ll need consent; repair is often prioritised before replacement—speak to your local officer first.
• Conservation areas: rules vary; even colour changes can trigger applications, so check early. Check the planning-portal

Thermal, security & noise—specs that matter

• Glazing: A-rated double is plenty for most; 44mm triple available on R7/R9 and aluminium sets
• Frames: multi-point locking, internally beaded glazing, choice of welded or mechanical joints
• Acoustics: laminated and asymmetric glass often beats “just more panes” for noise hot-spots

Popular colours & finishes

From Agate Grey and Chartwell Green to English/Irish Oak, you can mix dual-colour inside/out with traditional or contemporary handles.

Compare Your Flush Casement Window Choices

In KJM’s showroom in Andover Hampshire, we have some good choices for you to choose from. We can certainly recommend a visit to you can view these. Our offering includes the Sheerline Prestige aluminium window, uPVC offerings include the Residence 9 and Residence 7 system. Another uPVC offering is the stunning Deceuninck flush window. Finally, we do have a timber offering flush casement that can be manufactured in engineered softwood, hardwood or even Accoya a market leading long-life timber.

Sheerline Flush aluminium window

The Sheerline aluminium system was new to KJM in 2023. It has a number of options and can be glazed with the very best double glazing or market leading 44mm triple glazing.

Deceuninck Flush Casement uPVC Window

Deceuninck offer a wide range of colours to choose from. Graf welds and mechanically jointed frames make these a traditional and elegant style of these window that will complement any building they are installed into.

Residence 7 and Residence 9 windows

Residence 9 and Residence 7 windows are an eclectic blend of traditional aesthetics and innovative design. Whatever period your property is, Residence 9 windows will look great as they copied historical design and considered conservation guidelines. Both window systems are available with market leading 44mm triple glazing.

Timber windows

With the beauty of timber all window designs can be achieved. Our preferred supplier is the long establish George Barnsdale, who can manufacture flush casement to any specification

Choose your flush casement window

• uPVC Flush Casement Windows
• Residence 7 Windows
• Residence 9 Windows
• Sheerline Aluminium Flush
• Smarts Alitherm 400 Flush
• Timber Flush Casement

Flush casement windows FAQ

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Mark Pearce

With over four decades in the glazing industry, Mark Pearce has been at the heart of KJM Windows & Conservatories since 1983. Starting as a building labourer, he quickly rose through the ranks, working as a window and door installer from 1984, a factory operator manufacturing windows later that year, factory manager in 1992, and joining the sales team in 1994. Becoming a Director in 2002, and finally, the sole owner in 2010, Mark Pearce is truly a double glazing expert and has led KJM to become a leading supplier of high-quality windows, doors, and conservatories across Andover and the South of England.

Mark Pearce is a highly experienced specialist in the double glazing industry, having built his knowledge from the ground up through hands-on experience in installation, manufacturing, sales, and business management. Beyond his role at KJM, Mark is a keen blogger, writer, and traveller, often sharing insights on the latest innovations in the home improvement industry.

Latest posts by Mark Pearce (see all)

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