Built around a timber frame and operated on traditional cords, weights and pulleys, our traditional sash window is internally beaded for security and finished with slim glazing bars. The result is an authentic sash you can live with: warmer, quieter and safer than the original.
The following specifications apply to our traditional sash windows . Bespoke configurations are available to suit your project requirements.
| 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 | 39 x 45 mm top rail and stiles, 90 x 55 mm bottom rail, 45 x 55 mm meeting rail |
| 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 | Internally glazed with timber beads |
| Air permeability | 450 Pa (Class 3) – EN 12207:2017 |
| Water tightness | 200 Pa (Class 5A) – EN 12208:2002 |
| Wind resistance | 1600 Pa (Class 4C) – EN 12210:2016 |
| Whole window U-value | 1.5–1.4 W/m²K to EN ISO 10077-1:2006 |
| Whole window acoustic rating | Rw 29–38 dB tested to BS EN ISO 10140-2:2010 |
| Anticipated life expectancy | 60 years with regular maintenance |
| 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 (Teknos Aqua prime 1410, Aqua mid 5200, Aqua top 2600) |
| Colour | White – RAL 9016 (standard). Any RAL from RAL Classic range. Stain from Zyle Fenster stain range |
| Glazing | Double glazed, 4/16/4 Low-E top sash – 4 toughened/16/4 toughened bottom sash (standard). Ug-value 1.1 W/m²K; g-value 0.52 |
| Glass standard | Factory-fitted 24–44 mm sealed double-glazing units tested to BS EN 1279, argon filled |
| Perimeter spacer bars | White warm edge perimeter spacer with white warm edge integral spacers (standard). Silver and black optional |
| Solid bar | Ovolo 1, Ovolo 2, Lambs Tongue |
| Glazing bars | Applied bars to both faces of sealed unit, fixed with double-sided glazing tape and capped with clear silicone |
| 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 |
| Moisture content | 12% +/- 2% on delivery |
| Ironmongery | Lockable Fitch fastener and two finger pulls to bottom sash. Options in antique brass, polished chrome, satin nickel, polished brass, matt bronze, polished nickel |
| Cill | Hardwood. Projections 35–110 mm |
| Horns | Solid feature horns to top sashes included as standard |
| Restrictors | Optional restrictors limiting opening to 100 mm |
| Fixing | Installation per Zyle Fenster recommendations and best building practice |
| Warranty | 10-year manufacturing and material defects; 10-year opaque finishes; 6-year stain finishes; 10-year sealed unit seals; 2-year ironmongery |
Download the Traditional Sash Window brochure, datasheets and CAD details for your project.
The traditional sash window has been a defining feature of British domestic architecture for centuries. Our handcrafted versions preserve that classic design – complete with traditional timber horns, authentic mouldings, and counterbalance cord and pulley systems – while meeting the expectations of today’s living space requirements.
For period homes, conservation areas, and listed buildings, the box sash window remains the popular choice. It offers unique character that modern alternatives simply cannot replicate, making it an excellent choice for property owners seeking to preserve the authentic look of their building without sacrificing energy efficiency or comfort.
Every timber frame is manufactured using mortise and tenon joints, glued and mechanically fixed for structural integrity and long-term durability. Frames and sashes are produced from engineered redwood as standard, with options including Accoya, engineered hardwood, and European oak for projects with more specific requirements or environmental priorities.
Finished with a three-coat micro-porous factory spray in a wide range of colours – including any RAL classic shade or a choice of stain – our traditional sash windows are as considered in their appearance as they are in their construction. The result is a more comfortable living environment and complete peace of mind for clients and specifiers alike.
Our traditional sash windows retain the elegance of classic timber designs while benefiting from modern materials and construction methods. Smooth operation and durable finishes make them a dependable choice for both period-style homes and newer properties seeking a timeless appearance.
Honest answers to the questions homeowners and self-builders ask when restoring a period home or specifying traditional timber sash windows for a new build.
Yes. Sash horns, glazing bar profiles and meeting rail proportions are all made to suit Georgian, Victorian or Edwardian properties, with applied bars in Ovolo or Lambs Tongue profiles.
They will. Whole window U-values of 1.4 W/m²K and acoustic performance up to 38 dB make a significant difference compared with original single-glazed sashes, especially in town and city locations.
Internal beading, multi-point locking and security-rated glazing allow the window to meet PAS 24:2016, the same standard used to certify modern Secured by Design windows.
With routine maintenance and recoating, traditional sash windows have an anticipated service life of around 60 years, supported by a 10-year manufacturing warranty.
Yes. Any colour from the RAL Classic range or a wood stain from our range can be hand-applied at the factory, so the windows arrive on site fully finished.
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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