Lerwick Town Hall, a Category A-listed civic building dating from 1883, is the most important public building in Shetland. GRAS was commissioned to deliver an ambitious £1.2 million conservation and repair project focused on safeguarding the building’s nationally significant collection of secular stained glass windows. These windows were designed and created by several leading makers of the late nineteenth century.

Over many years, the stained glass had suffered significant damage from the harsh salt-laden maritime environment. Previous conservation attempts included the application of flexible polycarbonate sheeting to the exterior, but this measure proved insufficient to protect the glass from ongoing deterioration.

To address these challenges, the project adopted the traditional isothermal glazing approach. GRAS, in collaboration with Cannon MacInnes, developed and installed a newly patented non-ferrous isothermal glazing system tailored to the unique technical demands of the building and its environment. This system isolates the historic glass from external conditions while allowing full adjustability and accessibility for future maintenance.

In addition to the glazing improvements, the most severely deteriorated masonry around the window openings was carefully removed and replaced with salt-resistant stone possessing high cohesive strength. This material was selected to ensure enhanced longevity and resilience against the extreme maritime climate.

These technical advancements, combined with the introduction of sensitive interpretation for visitors, have not only opened the building to a wider public but have also increased visitor numbers in the area. The project has significantly improved the long-term prospects of Lerwick Town Hall and strengthened its role as a cultural and architectural landmark in Shetland.