Timber Casement Windows

As all properties are different, we offer two ranges of timber casement windows with a wide variety of design and performance features to suit your needs

All our casements are made-to-measure, meticulously crafted and easily exceed the latest British and European safety and performance standards. Whether you are looking for traditional styling, exceptional weather resistance, high thermal efficiency, or enhanced security, we know we can supply just the right casements for your home and your lifestyle.

Our casement windows are available as Flush or Stormproof casements. They can be either internally or externally beaded.

Flush Casements

Our popular Timber Flush casements have a classic beauty and simplicity that enhances modern homes whilst also complementing older traditional and heritage properties

Made-to-measure from sustainably sourced softwood timber, the flush design has a hand crafted, sleek look with decorative internal mouldings, internal or external beading, and a choice of glazing bars and traditional hardware.

Immensely practical and versatile, these outward opening casements can be side hung or top hung and offer a choice of hinges for multi-compartment frames and three operating modes, including fully reversible opening to allow for easy cleaning.

Storm Casements

Timber Storm casement windows are extremely strong and stylish, providing outstanding levels of energy efficiency, acoustic performance and security credentials

Designed to withstand the harshest weather conditions, they are made from durable, sustainably sourced timber from Scandinavia, featuring high-performance glazing as standard.

Available in both top hung and side hung configurations, they combine practicality with a high level of craftsmanship that can be customised with either internal or external beading, decorative internal mouldings on the sash, frame and glazing bars for a touch of elegance.

Opening Functions

The below product renderings detail the opening method only and are not fully accurate depictions of the product range stated.

Fixed Windows

Fixed window units can’t be opened. They are often used as sidelights or top-lights to doors and windows to generate additional light or adjacent to an opening sash to achieve a specific architectural design.

Fixed windows are available in both double & triple glazing.

Fully Reversible

The fully reversible opening function can reverse on concealed hinges to allow for cleaning from the inside. The hinges open to a maximum of 170 degrees.

The fully reversible opening function is available in double & triple glazing.

Side Guided

The side guided opening function has an opening position of up to 90 degrees on concealed friction hinges, which also allows for easy cleaning from the inside.  

The side guided opening function is available in double & triple glazing.


Side Hung (System 2000 only)

Side hung windows open out on visible butt hinges.

The side hung opening function is available in double & triple glazing.

Tilt and Turn

Tilt and turn windows give you the option of using the tilt function to allow ventilation into your room. You can also open the window inwards, providing easy cleaning from inside.

The Tilt and Turn opening function is available in double & triple Glazing.

Top Guided

Top guided windows open out on concealed friction hinges.

The top section of the frame slides down and the bottom of the sash is pushed out giving highly effective ventilation.

The top guided opening function is available in double & triple glazing.

Design Options

Profile options
Our casement windows are available as Flush or Stormproof casements.
They can be internally or externally beaded.


Our range of handle choices.

Glass Options

Allan Brothers offer a wide range of glass options available to suit your needs.

Safety Glass

  • Toughened Glass can withstand 3.5 times more weight than ordinary glass. When the glass breaks it shatters into tiny pieces, which reduce the risk of injury.
  • Laminated Glass is made up of two sheets of glass held together by a clear film. The glass will break when it is overloaded, but the glass fragments remain safely held together by a plastic film. This is to reduce the risk of injury should this glass break.

Opaque/Obscure Glass – generally for privacy purposes.

Solar Control Glass – is used to reduce the effects of solar gain in south facing rooms.

Sound/Noise reduction glass – reduces sound transmission through the window.

Coloured Glass – is available in a variety of different forms.

Self-Cleaning Glass – is ideal for windows that are hard to reach and clean.

Obscure options

For reasons of either privacy or style our patterned glass provides a range of attractive options. From classic to contemporary we offer a textured glass to suit most requirements you may have.

Developed to achieve a minimum of heat loss our timber casements are double-glazed with a spacer bar located between the two panes.
A bar profile is then bonded to both sides of the window.
Bars are available in a 25 mm, 40 mm or 56 mm profiles.

TV90 Air Vent

Available in White, Brown, Satin Chrome, Polished Chrome and Brass.


Our standard colour and stain choices – many more available.