Timber Casement windows are standard in millions of homes, but ours are anything but ordinary. Available in a wide range of shapes, styles and sizes, with or without glazing bars in any colour you can think of, they offer exceptional performance and beauty in equal abundance.
Whether you live in a historic Grade II listed building or a contemporary new build, an Edwardian terrace or a medieval church conversion, our timber casement windows can be designed to match your requirements and those of the planning/conservation officer.
We offer two versions of timber casement windows. Flush casements (or traditional) where the window or sash sits flush to the frame and stormproof which sits proud of the frame and ensures additional protection from bad weather. Both options perform equally well due to our team’s excellent research and development skills and tested design process.
Architects and Specifiers find us on SpecifiedBy
Tested to exposure category 2000 – the highest classification
A rated as standard; Triple glazed options available
Fitted as standard allowing easy cleaning from the inside
Environmentally friendly designs, materials and processes
Great performance as standard and extensive test data to guide specification for optional enhanced acoustic performance
Secured By Design and PAS 24 compliant
Available in a range of widths and styles
Dual seal design provides excellent draught proofing
Our ranges and options make it possible for you to achieve the exact look and feel to meet your property style and desired outcome.
See the projects where this product has been installed.
CASE STUDY
CASE STUDY
CASE STUDY
CASE STUDY
Performance and technical specifications are both available for our Timber Casement Windows.
Performance
Thermal | As Standard | Best |
---|---|---|
U-Value | 1.3 | 0.9 |
Energy Rating | A | A+ |
g-Value | 71% | As Required |
LT | 81% | As Required |
Acoustic | ||
---|---|---|
Rw | 30dB | 41dB |
Weather | ||
---|---|---|
Classification | 2000 (BS6375 Part 1) | |
Air | Class 4 (EN 12207:2000) | |
Wind | Class 7A (EN 12208:2000) | |
Water | Class C5 (EN 12210:2000 Class C5) |
Operation & Strength | ||
---|---|---|
Classification | Pass (BS6375 Part 2) |
Security | ||
---|---|---|
PAS 24 / Part Q/ Secured by Design | Pass (as option) |
Sustainability | ||
---|---|---|
FSC Chain of Custody | Yes |
CAD Drawings
NBS Data
Performance
Thermal | As Standard | Best |
---|---|---|
U-Value | 1.6 | 1.2 |
Energy Rating | B | A |
g-Value | 71% | As Required |
LT | 81% | As Required |
Acoustic | ||
---|---|---|
Rw | 30dB | 41dB |
Weather | ||
---|---|---|
Classification | 2000 (BS6375 Part 1) | |
Air | Class 4 (EN 12207:2000) | |
Wind | Class 7A (EN 12208:2000) | |
Water | Class C5 (EN 12210:2000 Class C5) |
Operation & Strength | ||
---|---|---|
Classification | Pass (BS6375 Part 2) |
Security | ||
---|---|---|
PAS 24 / Part Q | No (high security spec available) |
Sustainability | ||
---|---|---|
FSC Chain of Custody | Yes |
Performance
Thermal | As Standard | Best |
---|---|---|
U-Value | 1.3 | 0.8 |
Energy Rating | A | A++ |
g-Value | 71% | As Required |
LT | 81% | As Required |
Acoustic | ||
---|---|---|
Rw | 30dB | 41dB |
Weather | ||
---|---|---|
Classification | 2000 (BS6375 Part 1) | |
Air | Class 4 (EN 12207:2000) | |
Wind | Class 7A (EN 12208:2000) | |
Water | Class C5 (EN 12210:2000 Class C5) |
Operation & Strength | ||
---|---|---|
Classification | Pass (BS6375 Part 2) |
Security | ||
---|---|---|
PAS 24 / Part Q | Pass (as option) |
Sustainability | ||
---|---|---|
FSC Chain of Custody | Yes |
Find out more about the range of timber windows and doors we manufacture.
If you are looking for a heritage timber casement window style, we can also provide traditional butt hinges rather than friction hinges.
Our timber casement windows are available with U-values of 1.2 W/m2K with double glazing and 0.8 W/m2K with triple glazing. This comfortably meets the Part L building regulations 2022.
If you like the look of a regency sash window but need a more budget-friendly option, we can offer regency mock sash casement windows. These can be finished with decorative horns to provide an authentic sash window appearance.
View our case studies and galleries to see how we have designed bespoke timber casement windows to suit a variety of domestic and commercial projects across the United Kingdom.
There are multiple glazing options available, including double glazing, triple glazing, and acoustic glazing. We can also provide glazing features such as decorative glass, safety glass, and low-E glass to meet specific needs.
Each option is available with customisable frame finishes to match your design preferences, with many of our glazing options, such as low E glass, being energy efficient, which helps reduce overall energy costs and environmental impact.
To get a quote, you can contact George Barnsdale directly. Our team will discuss your project requirements, help you choose the right options, and provide a tailored quote based on your specifications.
Timber casement windows from our manufacturers are designed to be highly energy-efficient. They feature double or triple glazing, weatherproof seals, and thermal insulation that help reduce heat loss and lower energy bills.
By combining the properties of timber with the select glazing options, our casement windows not only improve energy efficiency but also enhance the comfort and performance of any space. With sustainable timber sourcing and construction, these windows offer an environmentally responsible choice that doesn’t compromise on longevity.
Yes, our timber casement windows are an excellent choice for listed and heritage properties, as they provide a classic look required by conservation standards. We also work closely with clients to ensure compliance with planning requirements in the UK.
Founded in 1884, George Barnsdale is a family run business manufacturing high-performance timber windows and doors in Donington, Lincolnshire and offering a nationwide project management and installation service.
© 2025 George Barnsdale | High Street Donington, Spalding, Lincolnshire PE11 4TA | Phone: 01775 823000
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