Timber Casement Windows
Made-to-order timber casement windows with traditional flush profiles and modern performance. Ideal for period homes across London. Request a free quote today.
Traditional Timber Casements, Made for Modern Homes
Our timber casement windows stay true to the proportions and understated appearance of traditional joinery.
Behind this traditional appearance, modern glazing, concealed draught sealing, weatherseals, and contemporary operating mechanisms provide the comfort and ease of use expected from a new window.
Made to Suit Your Property
01 Flush profile
Opening sashes sit neatly in line with the outer frame when viewed externally, creating the restrained appearance associated with traditional timber casement windows.
02 Made-to-order frames
Frames can be produced for arched heads, angled reveals, and shaped openings, with different opening configurations available to suit the property.
03 Period detailing
Ovolo and Lambs Tongue profiles, marginal glazing bars, and slim outer frame and sash options allow the detailing to reflect the surrounding architecture.
04 Glazing layouts
Fixed and opening lights can be combined in a range of configurations, with glazing patterns developed around the proportions and character of the window.
Learn More About Our Timber Range
Timber Casement Windows for Period Properties
Replacing casement windows in a period home calls for careful attention to the original architecture.
Our casements can be specified around the existing architecture, making them particularly suited to sympathetic replacements in Georgian, Victorian, and Edwardian homes.
Conservation Areas & Listed Buildings
Replacing windows in a conservation area or listed building can involve specific requirements, which vary by property and location.
We’ll assess the existing windows before recommending an appropriate specification, with careful consideration given to proportions, sightlines, glazing, and traditional detailing.
Where required, alternative glazing options can also be explored.
Performance at a Glance
Modern glazing, secure locking, and weather sealing are built into the timber casement specification, providing improved thermal and acoustic performance while retaining the slim proportions of traditional joinery.
- Glazing: 24mm Low-E double-glazed unit as standard, with an argon-filled cavity and warm-edge spacer
- U-value: 1.3 W/m²K with standard double glazing
- Energy rating: A or A+
- Security: Tested to PAS 24:2016, with multipoint locking and internally beaded glazing
- Acoustic performance: 31dB, with potential performance of up to 39dB when specified with acoustic laminated glass
- Other glazing options: Slimmer glazing units, vacuum glazing, and some triple-glazed specifications, plus obscure, toughened, and laminated glass
Performance varies according to the glazing and window specification selected.
Everyday Security Features
- Our timber casement windows are tested to PAS 24:2016, with multipoint locking and internally beaded glazing providing added reassurance.
- Side- and top-opening sashes use friction hinges, with easy-clean functionality available to make routine maintenance more straightforward.
- Deventer weatherseals help provide a secure seal when the window is closed, supporting everyday comfort and performance.
- Traditional hinges can also be specified where appropriate, subject to Document Q requirements.
30 year guarantee
on timber
10 year guarantee
on paint
Smaller energy bills
and carbon footprint
Casement Window Styles
01 Styles and finishing options
Each timber casement window can be specified around the architecture of your property, with a choice of configurations, colours, and window furniture.
02 Configurations
Frames can be produced for arched heads, angled reveals, and shaped openings, with different opening configurations available to suit the property.
03 Colours
Our timber casement windows are available in hundreds of RAL colours, allowing the finish to complement both traditional and contemporary properties.
Stain finishes are also available where a natural timber appearance is preferred.
04 Window furniture
Choose from Balmoral, Barrington, Kingsley, Monkey Tail, and Opera handles, with corresponding stays available across the range.
A broad selection of finishes includes chrome, brass, bronze, black, and heritage-style tones.
Responsibly Sourced Timber
Our timber is sourced from responsibly managed forests, with FSC® certification helping to maintain environmental, social, and economic standards throughout the supply chain.
Modern manufacturing techniques are used to minimise waste, while careful engineering is intended to give the timber a long service life.
Timber also stores carbon throughout its lifespan, making responsible sourcing and durability important parts of the specification.
Our Cornish workshop combines traditional skills with modern machining technology to ensure every frame meets exact specifications. Choose from a range of timber:
Redwood
A versatile softwood valued for its thermal properties and engineered stability. Redwood reduces the risk of warping or twisting, making it an excellent choice for painted wooden sash or casement windows where fine detailing and long-term performance are essential.
Red Grandis
A plantation-grown hardwood with a uniform grain, Red Grandis balances durability with design flexibility. It accepts both paint and stain finishes, offering a resilient option for wooden bay and casement windows that must withstand exposure while maintaining a refined appearance.
Accoya®
One of the most advanced modified timbers available, Accoya offers exceptional resistance to rot, outstanding stability, and impressive energy performance. It is a future-proof choice for double-glazed wooden windows, providing a low-maintenance, high-durability solution for both Heritage and contemporary builds.
Why Choose Sash Windows London for Timber Casement Windows?
Getting timber casement windows right starts with understanding the building.
Founded in 2005, Sash Windows London has extensive experience working with traditional properties across London and the South East, including conservation areas and listed buildings.
Our made-to-order windows are manufactured in the UK, with specialists guiding your project from the initial consultation through to final installation.
Our Process
01 Consultation
02 Specification
03 Survey & manufacture
04 Installation
Find the Right Timber Casement Windows for Your Home
The right specification starts with the property itself.
Arrange a home visit, and we’ll assess your existing windows, discuss the most suitable casement style and configuration, and consider glazing, architectural detailing, and any conservation requirements.
Timber Casement Windows FAQs
What is a flush timber casement window?
A flush casement has an opening sash that sits neatly in line with the outer frame when viewed externally. This creates the restrained proportions associated with traditional timber casement windows.
Are timber casement windows double-glazed?
Yes. Our timber casement windows use a 24mm Low-E sealed double-glazed unit as standard, with an argon-filled cavity and warm-edge spacer.
Can timber casement windows be used in conservation areas?
They can be suitable for properties in conservation areas, although requirements vary by location and individual building. We can assess the existing windows and advise on an appropriate specification.
Can you match my existing casement windows?
Our timber casement windows are made to order, allowing the proportions, glazing patterns, profiles, and other details to be specified around the existing architecture of your property.
How energy efficient are timber casement windows?
Our standard double-glazed flush casement specification achieves a U-value of 1.3 W/m²K, with a Window Energy Rating of A or A+.
Are timber casement windows secure?
Yes. Our timber casement windows are tested to PAS 24:2016 and incorporate multipoint locking and internally beaded glazing.