Location: Glastonbury, Somerset

Project type: Semi-transparent BIPV rooflight glazing, heritage & community building

System size: ~6.3 kWp

Turning a new glass roof on a Scheduled Monument site into a quiet, six-kilowatt power station.

St Dunstan's House sits within the precinct of Glastonbury Abbey, next to the Grade II* listed Town Hall. Its transformation into a Community Health & Wellbeing Centre for Glastonbury Town Council, and designed by o2i Design, is one of the flagship projects of the Glastonbury Town Deal. At the heart of the scheme is a new glazed Atrium linking St Dunstan's House to the Town Hall, and Polysolar was appointed to design, supply and electrically connect the semi-transparent photovoltaic glazing that forms its roof.

The result is a roof that does two jobs at once: it floods the Atrium and the Festival Hall beneath with a wonderfully dappled natural daylight, and it generates clean electricity for the wellbeing centre, without a single visible solar panel anywhere on the historic roofline.

The Challenge

The site carries three heritage designations — a Scheduled Monument, a Grade II* listed Town Hall and the Grade II listed St Dunstan's House itself — so a conventional rack-mounted array on any existing roof slope was never going to be acceptable to planners or conservation officers. The design and construction team still wanted the scheme to generate its own renewable power, alongside the air source heat pumps and high-performance glazing specified elsewhere in the refurbishment. The one part of the building where solar generation and heritage sensitivity didn't have to compete was the new Atrium roof. This is a fully glazed structure with no historic fabric to protect, but located in the curtilage of the Grade II* listed Town Hall. The requirement was for the rooflight to let daylight flood the community spaces below and generate renewable energy.

Our Solution

Polysolar designed and supplied bespoke semi-transparent photovoltaic glazing to form the entire Atrium skylight, then delivered the electrical design and DC-side installation to bring the array onto the building's supply:

• 32 x Polysolar PS-MC semi-transparent glazing units, each a bespoke double-glazed unit with a 13mm PV laminate, 16mm argon-filled cavity and overall unit depth of 37.38mm
• 1900mm x 795mm panels, weighing 68kg each, engineered to sit within the Atrium's aluminium framework alongside the surrounding structural glazing
• 30% light transmission, so the Atrium and Festival Hall below stay naturally daylit rather than sitting under a solid roof
• Dual-MPPT string inverters, specified to 3-phase on site to match the building's supply, plus DC cabling, MC4 connectors and generation metering — all designed, supplied and installed by Polysolar through to the consumer unit
• 25-year performance warranty (90% of rated output for 10 years, 80% for 15 years)

The glass itself was fitted into the Atrium's framework by specialist glazing contractor The Standard Patent Glazing Company, with Polysolar providing the mounting design and full handover documentation. Polysolar then completed the DC electrical installation and worked with Bristol-based solar contractor Solar Sun & Air to connect, test and commission the array.

The Results

Installed capacity ~6.3 kWp

Panels 32 x Polysolar PS-MC, 198Wp each

Light transmission 30%

Performance warranty 25 years

Recognition RTPI South West Awards for Planning Excellence 2026 — Best Project & Best in Region

Solar Glass on a Scheduled Monument

St Dunstan's House shows what's possible when a heritage setting rules out a conventional array but the ambition for on-site generation doesn't go away. By building the photovoltaics into the roof glass itself, the Atrium generates real power for the wellbeing centre below while staying true to the sensitivity the site demands. There is no visible panel, no compromise on daylight, and no impact on the historic roofline it sits beside.

Sector: Heritage & Community | Client: Glastonbury Town Council | Project Lead: Dowlas Property Group | Architect: o2i Design | Contractor: Melhuish & Saunders
Photo Credits with thanks to Glastonbury Town Council.

Want a solar roof that works on a site where a conventional array can't? Get in touch to discuss your site: 01223 911534