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.
A complete service
from design to installation.
We purchased a combination of Alu-Clad windows, Lift & Slide doors and entrance glazing from Zyle Fenster for our family home.
Every member of the team was knowledgeable, approachable and highly professional. Manufacturing quality is outstanding and the installation was carried out with real attention to detail. Even after completion, they followed up to ensure everything was perfect.
It’s rare to find a company that delivers exactly what they promise. We would happily recommend Zyle Fenster to anyone building or renovating a home.
Seán & Emma R. – County Meath
Our architect specified Reynaers aluminium systems and recommended Zyle Fenster for the supply and installation.
The large glazing panels have completely changed the feel of the house while maintaining excellent thermal comfort throughout the winter. The installers were meticulous and every junction was finished beautifully.
It’s refreshing to work with a company that genuinely cares about delivering a quality result.
Niamh F. – County Clare
We chose Schüco aluminium windows and doors through Zyle Fenster for our contemporary home.
Everything about the experience was professional. From technical advice through to installation, the team demonstrated real expertise. The slim profiles look fantastic and the quality of the finish is exactly what we hoped for.
A premium product installed by a premium company.
David L. – County Waterford
Our conservation project required slim glazing without compromising performance, and Zyle Fenster recommended their vacuum glazed timber sash windows.
The result is outstanding. The traditional appearance has been preserved while the improvement in warmth and noise reduction is remarkable. You simply wouldn’t know they contain such advanced technology.
Excellent communication, excellent installation and an exceptional product.
Michael & Sarah K. – County Kilkenny
Finding authentic timber sash windows that also met modern energy standards wasn’t easy until we found Zyle Fenster.
The finished windows perfectly suit our Victorian home while dramatically improving comfort. They operate beautifully and the attention to detail is outstanding.
The installation team treated our home with great respect and left everything spotless each evening. We have received countless compliments from neighbours.
Margaret C. – Dublin
We wanted a large glazed feature overlooking the garden while still achieving excellent thermal performance. The timber curtain wall supplied by Zyle Fenster exceeded every expectation.
The craftsmanship is remarkable and the amount of natural light it brings into the house is incredible. Our architect was particularly impressed with the technical knowledge and attention to detail shown throughout the design process.
Professional, reliable and extremely high-quality workmanship.
Patrick D. – County Wicklow
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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