Restoration of Elizabeth Castle
Standing sentinel over St Helier Harbour, Elizabeth Castle is one of Jersey’s most iconic landmarks—an island fortress spanning 24 acres and over 15 centuries of history.
Each window was handcrafted using engineered redwood and red grandis, materials chosen for their dimensional stability, weather resistance, and sympathetic grain character.
Project & Historical Context
Standing sentinel over St Helier Harbour, Elizabeth Castle is one of Jersey’s most iconic landmarks—an island fortress spanning 24 acres and over 15 centuries of history. The site’s story begins in the 6th century with the hermit Helibert (later Saint Helier), and evolves through eras as an abbey, a stronghold replacing Mont Orgueil in the 16th century, a refuge for Charles II, a British garrison until 1923, and a German fortress during WWII.
Now under the stewardship of Jersey Heritage, the Castle is undergoing an ambitious, long-term conservation programme involving over 30 historic structures. Our involvement formed part of Phase One, focusing on window and door restoration within the original Officer’s Barracks—central to the Castle’s historic function. Following a £6m grant, these buildings are being returned to their original use as officer’s quarters, offering visitors a rare opportunity to stay overnight within this extraordinary setting.
Craftsmanship
Mumford & Wood were commissioned to design and manufacture 35 bespoke classic box sash windows and one entrance door, faithfully replicating the Castle’s original fenestration. Each window was handcrafted using engineered redwood and red grandis, materials chosen for their dimensional stability, weather resistance, and sympathetic grain character.
A key feature of the design was the beaded liner detail—a subtle radiused bead that softens the visual transition between frame and sash, replacing the sharp edges of modern joinery. This historically faithful touch reintroduced the elegance of earlier craftsmanship.
The windows were double-glazed with through bars, each pane individually cut, bedded, and fixed with sprigs before being sealed with traditional linseed oil putty—a meticulous, hand-applied process ensuring both authenticity and performance.
Finishes were completed in Dulux Heritage DHY (A Heritage White), colour-matched to the original pale yellow tone, and paired with antique brass ironmongery for a tactile, period-appropriate finish.
Evidence of Conservation & Restoration
Our approach was guided by conservation best practice principles:
- Measured Surveys: Every opening was individually recorded to accommodate centuries of irregular masonry and structural movement.
- Material Specification: Engineered timber cores veneered with red grandis ensured durability without sacrificing authenticity.
- Joinery Detailing: Mortise-and-tenon joints were traditionally pegged and glued to resist racking under high coastal wind loads.
- Glazing Methods: Modern insulated glass units were sized to maintain authentic putty sightlines, avoiding any visible “stepped” profiles that would detract from the historic aesthetic.
Design & Technical Problem-Solving
Integrating 21st-century performance into a 17th- and 18th-century military structure presented significant challenges—especially where apertures were irregular, asymmetrical, and often far from square.
To overcome these constraints, our team implemented several bespoke solutions:
- Variable Frame Depths: Each window frame was uniquely profiled to match its masonry reveal.
- Historic Bead Geometry: Profiles were reverse-engineered from surviving fragments to accurately replicate period joinery.
- Marine-Grade Finishes: Multi-stage priming and breathable coatings were applied to protect against Jersey’s salt-laden coastal environment.
- Hardware Compatibility: Custom-sourced antique brass hardware matched the tone and patina of existing historic fittings.
Excellence & Achievement
Completed in early 2025, this two-year programme exemplifies the balance between heritage fidelity and modern technical innovation. The restored sash windows now preserve the Castle’s historic character while meeting today’s standards for energy efficiency, durability, and low maintenance.
Our achievements include:
- 100% bespoke fabrication for every aperture
- Preservation of original sightlines critical to the Castle’s visual identity
- Fully hand-finished glazing and painting for a truly period-correct appearance
Summary Statement
For more than four centuries, Elizabeth Castle has stood as Jersey’s maritime guardian—a living record of the Island’s history. Our work ensures that one of its most defining architectural features, the classic sash window, continues to reflect the artistry, precision, and respect for tradition that heritage conservation demands.
This project stands as a lasting example of how traditional craftsmanship and contemporary engineering can work in harmony to keep history alive for generations to come.
