The main roof build-up included self-adhesive vapour control layers, 130mm PIR insulation, thermally activated underlays and charcoal mineral capsheets to provide a durable and thermally efficient waterproofing solution. The plant room roof was also upgraded with a fully waterproofed insulated roofing system complete with 50mm PIR insulation and charcoal capsheet finish. Concrete slab walkways on pedestal supports were installed to create safe maintenance access routes across the roof areas. Parapet upstands, perimeter details and rooflight upstands were fully waterproofed using insulated detailing systems with PIR angle fillets and thermally activated membranes to ensure all roof edges and penetrations remained weatherproof. New 110mm rainwater outlets and lead collars to soil vent pipes were installed to improve roof drainage and detailing. The project also included the installation of new rooflights, Bilco access hatches, fixed companionway ladders and step-over access units with handrails to provide safe access between roof levels and plant areas.