Glasgow City Council (GCC) appointed us to carry out a structural appraisal of the Category ‘B’ listed Tollcross Conservatory in Tollcross Park. The Conservatory was potentially constructed around the same time as Tollcross House in the late 1850s. The listing is concise and merely states “viz circa 1858, Conservatory, Latin-cross-plan, domed at crossing, apsidal ends, cast-iron and glass, scroll-console buttresses”. The building is lightweight and a hybrid structure amalgamating timber, wrought iron glazing bars, brick dado walls and a cast iron panelised system.
The Conservatory underwent major refurbishment in October 2000 as part of a wider Lottery-funded Millennium project which included the large cable-stayed new-build extension to the north of the conservatory structure.
Our approach to the project was to holistic view with the primary aim of making the building usable again whilst retaining as much of the original structure and principles.
The initial assessment evaluated the structural capacity of the glasshouse and its ability to accommodate alterations, including determining the actions and interventions necessary to bring the building back into use. This included detailed surveys and measurements of the original frame alongside detailed material testing (metallurgy, stone compression and timber rot).
The final solution for the glasshouse retained all of the original astragals, mullions and decorative column bases of each of the wings and recreated the central dome with discrete steel frame replicating the original timber construction in a more robust construction. The re-use of glazing items was made possible utilising compound design of the wrought iron and glass panes, replicating the original structure whilst introducing modern laminate toughened glass.
The central dome frame was replaced in steel after the Timber Rot survey exposed the extend of degradation and section loss within the original members. Previous repairs to the frame had been piecemeal and nearly a century of water ingress had caused significant movement. The new frame was carefully considered, and steel sections chosen to closely match the original timber sizes and layout resulting in a new structure that matched the historic layout whilst providing a more robust and durable solution for the future of the building.
Further to the main structural works Narro were responsible for detailing and managing significant stone repairs to the sandstone bases and integrating new service runs within the ground bearing slab.
