Sash bay windows are a traditional feature found across Georgian, Victorian, and Edwardian homes. They project outward from the wall and use vertical sliding sashes within each frame. This style increases floor area, improves sightlines, and allows more natural light into the room. Still widely used in London today, sash bay windows suit both restoration work and properties that require architectural continuity.
Why Choose a Bay Style with Sash Mechanism?
A bay structure fitted with sash windows offers both functional and architectural advantages. The projection creates depth inside the room and opens up wider views, while the sash mechanism preserves the look expected in period properties.
Modern sash systems, including double glazing, slimline units, and vacuum glass, deliver significant thermal and acoustic improvements over older single-glazed designs. This means better insulation, lower energy use, and a quieter interior – without compromising on the style required for heritage or conservation settings.
The Benefits at a Glance
- Increased natural light – The bay projection allows more daylight to enter from multiple angles, brightening the interior.
- Greater sense of space – Extending beyond the external wall, bay windows add usable floor area and open up the room.
- Architectural consistency – Sash bay windows match the proportions and detailing of period facades, maintaining a coherent exterior.
- Improved outlook – The angled format offers wider, more open views compared to flat window frames.
- Built-in potential – The recess can be adapted for window seating, shelves or extra storage without altering the structure.
The Best Sash Bay Windows for Listed and Conservation Homes
We supply timber sash bay windows specifically built to meet the demands of conservation areas and listed properties. Designs can be matched to original window styles, with support available for planning applications where approval is required.
Our timber frames are made from Red Grandis or European Redwood – durable timbers chosen for their stability and visual consistency. Customers can specify Kensington, Westminster, or Richmond horn detailing, run-through glazing bars, and a range of mouldings to suit the property’s age and status.
Recommended Glazing for Period Homes
Slimline double glazing or single-glazed units are also available to comply with heritage regulations while improving efficiency and performance. Every window is made to order, ensuring the correct visual and technical fit.
Spiral Balance vs Cord & Weights
Sash bay windows can be built with either spiral balance or cord and weight mechanisms.
- Spiral balances are compact and hidden, offering smoother operation and less disruption to the surrounding wall space (useful in tighter bays or modern refurbishments).
- Cord and weight systems, by contrast, use traditional pulleys and visible boxes, which are often preferred in listed or heritage homes where historical accuracy is essential.
- Both options are reliable and secure, but the right choice depends on the property’s age, planning constraints, and interior requirements.
How to Customise a Sash Bay Window
Speaking for our range, all frames can be finished in any RAL colour, with the option for dual paint to match interior and exterior schemes. A selection of timber stains is also available for projects requiring a natural look. Hardware can be specified in various finishes, including polished chrome, satin chrome, brass and antique tones – covering fasteners, restrictors, lifts and pulleys.
Glazing options include acoustic glass for noise reduction, obscure or frosted glass for privacy, and decorative leaded styles. Triple glazing is also available where higher thermal or acoustic performance is needed.
Every window is manufactured to order in our Cornwall facility, ensuring accurate reproduction of period features and full control over detail.
How Sash Bay Windows are Installed
The installation process begins with a home consultation, followed by a detailed quote and an optional showroom visit to review samples. Once confirmed, a site survey is carried out to take precise measurements. All sash bay windows are then manufactured to specification and a fitting date is arranged.
Add Light, Space and Style with Sash Bay Windows
Ready to discuss sash bay windows for your property?
Book a free home survey to get expert advice on your home and location, or visit our London showroom to view samples and finishes in person. You can also refer a friend or neighbour and receive a £150 Love2Shop or John Lewis voucher if they go ahead with an order!
FAQs
Can sash bay windows be double glazed in listed buildings?
Yes – where planning allows, slimline double glazing can be used to replicate the look of single glass while improving energy performance. We also offer single-glazed options where required by local authorities.
Are bespoke bay window shapes possible (e.g., angled, curved)?
Yes. All sash bay windows are made to order, including angled or faceted bays. Curved bays may require specialist joinery, which can be discussed during a site survey.
What guarantees do they come with?
Timber sash windows come with a 30-year guarantee against rot and decay. Paint finishes, glazing, and installation are covered for 10 years. Ironmongery carries a 5-year guarantee.
