Built on traditional mortise and tenon joinery and externally putty-glazed, our Heritage Sash retains the authentic appearance of the original. Slimline double glazing, concealed draughtproofing and discreet ironmongery bring modern comfort without altering the look of your home.
Frame, sash, glazing and finish details for your architect, conservation officer or planning consultant.
| Product guidance – as standard | |
| Frame | 100 x 140 mm (lining width x frame depth). Mortise and tenon joints, glued and mechanically fixed |
| Sash | 39 x 45 mm top rail and stiles, 90 x 55 mm bottom rail, 45 x 55 mm meeting rail |
| Mullion / transom | 200 mm wide (130 mm for triple sash with fixed outer sash) |
| Sill projection | 35 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm, 110 mm |
| Staff / parting beads | Timber |
| Wood moisture content | 12–19% |
| Glazing beads | External traditional putty glazed |
| Product Specification | |
| Material | Frame and sashes engineered redwood, bottom cill in solid hardwood (standard). Engineered hardwood, Accoya, European oak optional |
| Finish | Three-coat spray-applied factory finish using water-based microporous paint/stain |
| Colour | White – RAL 9016 (standard). Any RAL from RAL Classic range. Stain from stain range |
| Glazing | Double slimline glazed, 4/6/4 Low-E top sash – 4 toughened/6/4 toughened bottom sash (standard). 4 mm or 6 mm single toughened glazing optional |
| Perimeter spacer bars | White perimeter spacer (standard). Black optional |
| Solid bar | Ovolo 24 x 45 mm |
| Trickle ventilation | Concealed through frame head trickle ventilator. EA 1700, 4400, 5000 mm² |
| Child restrictor | Angel lock (standard). Traditional Sash Stop optional |
| Operation | Cord, weight and pulley system concealed within the frame |
| Timber species | Engineered laminated pine, hardwood or Accoya. FSC or PEFC certified |
| Horns | Solid feature horns to top sashes included as standard |
Download the Heritage Sash brochure, datasheets and CAD details for conservation submissions.
Our timber heritage sash windows are designed specifically for period properties, conservation areas, and listed buildings where maintaining the authentic look of the original fenestration is a planning requirement. Using traditional putty glazing, ovolo mouldings, and period-accurate profiles, each window is manufactured to be a faithful match to the building’s original design intent.
Heritage does not mean compromise. Our team draws on years of experience and in-depth knowledge of conservation requirements to deliver timber heritage windows that satisfy planning authorities, listed building officers, and exacting property owners alike. Smooth operation, precise fitting, and careful attention to detail are central to every window we produce.
Where planning conditions allow, our heritage sash windows can be specified with slim double glazing to improve thermal performance and energy efficiency significantly compared to original single-glazed windows. Advanced materials and modern technology are used throughout the manufacturing process to maximise performance within the constraints of a traditional profile.
From draught-proofing and concealed trickle ventilation to optional triple glazing in appropriate window styles, our timber heritage sash windows can be configured to meet the specific needs of each project. They represent an excellent investment for property owners looking to improve the comfort and thermal performance of a period home without compromising its historic character.
Heritage sash windows are carefully crafted to preserve the charm of traditional architecture while incorporating subtle modern improvements. Their classic sliding mechanism and authentic detailing make them ideal for period properties, while specialist glazing options enhance comfort without detracting from their historic appeal.
Here are the answers to the most common questions about our timber heritage sash windows. Contact our team for tailored advice on conservation and listed building projects.
A timber heritage sash window is a traditional design featuring two movable sashes that slide vertically within a timber frame. It uses period-accurate profiles, mouldings, and glazing methods – typically external putty glazing – to replicate the authentic appearance of original historic windows precisely.
Yes. Our timber heritage sash windows are designed with the specific needs of listed buildings and conservation areas in mind. We work closely with architects and conservation officers to ensure every window meets the required planning conditions and maintains the highest standards of period accuracy.
Yes. Our heritage sash windows can be specified with slim double glazing – a 4/6/4 Low-E unit – designed to sit within traditional putty-glazed profiles without significantly altering the visual appearance of the window. This improves modern energy efficiency while respecting the original aesthetic of the building.
Yes. Our heritage sash windows can be fitted with solid ovolo glazing bars in 24 x 45 mm profiles, replicating the appearance of original Georgian bar arrangements. These are solid bars rather than applied bars, ensuring an authentic traditional look appropriate for conservation projects.
Our standard specification uses engineered redwood for the frame and sashes, with a solid hardwood bottom cill. Alternative materials including Accoya, engineered hardwood, and European oak are available where specific durability, dimensional stability, or environmental requirements make them the preferred choice.
Whether incorporated into a modern contemporary new build or unlocking a period property, our curtain wall can reinvigorate a property by letting the natural daylight come flooding in.
Find out more about Dollar, ScotlandA complete service
from design to installation.
Zyle supplied Passive House windows for our new build, and the system met all project expectations. Airtightness and overall performance were delivered as specified, and their technical coordination on site was reliable and detail focused.
Private Owner
Mark Reynolds, Bristol
Our vacuum glazed sash windows provide an excellent balance between heritage sensitivity and modern performance. The slim glazing preserves the character of the property while significantly improving overall comfort. Installation was precise and professionally managed.
Private owner
Laura Mitchell, Southampton
The Passive House windows performed exactly as required within our project specification. Installation detailing, sealing, and overall execution were handled correctly, ensuring a high standard of delivery. A technically competent and reliable supplier.
Private Owner
Andrew Collins, Cambridge
We selected aluminum windows for their contemporary aesthetic and low maintenance. The proportions are well considered, and the finish quality is consistent throughout. Installation was efficient and carried out with strong attention to detail.
Private Owner
Rachel Adams, Reading
The triple glazed sash windows integrate seamlessly into the existing façade while offering a clear upgrade in comfort. Craftsmanship is evident in both joinery and installation, and the improvement in acoustic insulation is immediately noticeable.
Private Owner
Thomas Green, Nottingham
The Alu-Clad windows and doors introduced a strong architectural presence while maintaining a refined internal finish. Detailing, material quality, and consistency across the project are of a high standard. The process was structured and dependable from start to finish.
Private Owner
Olivia Bennett, Oxford
Whether you are an architect specifying for a new project, a self-builder planning your custom home, or a developer working to a programme, our team is here to help. Get in touch for technical advice, product information, or to request a quote.
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