Shire End is a glazed roof extension to a Grade II listed Victorian house in an Area of Outstanding Natural Beauty above the historic harbour of Lyme Regis and the Cobb. Designed by RAK Architecture, a cluster of glazed additions links old and new while framing expansive coastal views, including a frameless oriel seating window that creates a key social space within a double-height structural glass extension. Full-height ultra-slim sliding glass doors with a flush threshold detail open the glazed link to a sea-facing terrace, maximising daylight and uninterrupted views across the bay.
Products Used
Featured In
Project Partners
rak architecture
Location
Lyme Regis
Grade II listed glazed link design in a Lyme Regis AONB
RAK Architecture was commissioned to create new glazed volumes that would remain subservient to the original Grade II listed building while making the most of the setting and long sea views, including sightlines toward Golden Cap to the east. The existing house has a distinctive overlapping slate-tiled façade, reminiscent of fish scales, and the replacement extension needed to connect to the brick building with a frameless glazed link and mono-pitched roof. A discovered 1950s postcard informed the roofline and chimney reference, showing that an earlier outbuilding with a similar form once occupied the site. The new addition was deliberately smaller in scale and contrasting in materiality, combining black brick and slate cladding with a modern, oversized frameless glass oriel picture box window as a contemporary interpretation of the Victorian box bay window on the original house.
Frameless oriel window seat framing Lyme Regis coastal views
Extensive coastal views can be enjoyed year-round through the frameless oriel seating glass window, which forms a focal point and social space within the new double-height structural glass extension. The deep oriel window seat positions the sitter looking across the bay towards Golden Cap, turning the view into part of the daily experience of the home. By framing the landscape through a minimal, picture-window-like opening, the oriel creates a clear architectural moment that complements the listed building rather than competing with it.
Double-height glazed link with ultra-slim sliding doors and flush threshold
The structural glass link connects the old and new with a glazed roof designed to appear light and minimal, exposing both the reclaimed Welsh slate “fish scale” tiles of the original building and the new extension. A total of 3,500 overlapping slate tiles were used across the combined composition. The steel roof structure was carefully detailed so trusses align with the glazing bars of the ultra-slim framed sliding glass doors, creating a controlled, consistent rhythm through the glazed link. Full-height ultra-wide slim sliding glass doors open onto a terrace via a flush threshold with an integral drain, creating a seamless transition from inside to outside and supporting extended living space in summer.
Performance considerations
Marine-grade glazing was installed to support reliable performance in exposed coastal conditions. Double-glazed, thermally broken glazing with solar control coatings was used throughout to manage glare and heat gain while maintaining clear views. In summer, internal temperatures are regulated through ventilative cooling by opening the full-height slim sliders, three casement windows and stable doors as required, taking advantage of the prevailing coastal breeze. During winter months, solar gain through the extensive rear glazing helps create a comfortable daytime environment, supplemented in the early morning and evening by underfloor heating and a woodburning stove.
Technical details
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Slim sliding glass doors (minimal windows®)
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Sightline: 21mm
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Max tested sliding pane: 4.0m high / 8.5m² / 500kg
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Testing: Air Class 4 / Driving rain Class 7A / Wind Class C4/B5
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Aluminium windows (Sieger Legacy)
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Sightlines: 33mm fixed / 58mm casement / 76mm tilt + turn
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Glazing: 24–28mm DGU
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Performance + security: Uw 1.5 W/m²K*; Air Class 4 / Water Class 9A / Wind 2400 Pa; PAS 24
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Structural glass roofs (Invisio)
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Thermal: Ug 1.1 W/m²K (typ.); Uw 1.2 W/m²K (example reference unit 1.23m × 1.48m)
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Glass thickness: up to 37.5mm DGU (up to 62.5mm TGU)
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Size guidance: recommended single rooflight up to 1.5m × 3.0m
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Frameless glass links + oriel windows (Invisio structural glazing)
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Profile depth: 63mm (Invisio) / 72mm (Invisio+)
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Expected Uw: 1.1 / 0.9 W/m²K; max glass unit 41.5mm / 62mm
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Tolerances: minimum fixing setback 55mm; structure deflection allowance 5mm
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*Uw values are calculated per project and depend on configuration and glass specification.
The owner noted how the height of the glazed pitched roof and the volume of natural light make the space feel more expansive day to day, with the oriel window seat creating a sheltered place to sit “in the garden” while remaining inside. This approach is particularly well suited to coastal projects where the brief is to connect a listed home to the landscape through a restrained glazed link, without losing the character of the original building.
Are you working on a coastal project where it is all about uninterrupted views? To discuss your designs, contact us now!
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