The existing topsoil overburden to the roof and perimeter drainage had to be removed before any waterproofing works could begin. Approximately 2000m3 was removed by small machines and stockpiled on site, for eventual reinstatement.
Once stripped the entire roof and perimeter was washed and prepared by high pressure water jetting, prior to the priming and installation of a new adhered sheet waterproofing system.
Concrete repairs were carried out to areas of the roof, all upstands received cementitious fillets and the roof edge detail was improved using cementitious levelling mortar.
Once prepared approximately 5400m2 of new waterproof roof membrane was laid to the roof, along with 700m2 of a liquid polyurethane waterproof coating to the new improved edge detail. A joint overbanding system was applied to the perimeter roof/wall joint.
It was decided that a geocomposite deck drainage system would be laid over the new membrane as protection and to facilitate drainage over the full roof area.
The stockpiled topsoil was then re-instated to the roof with gravel drainage in the perimeter trench, followed by grass seeding to a total area of approximately 5760m2.
All works were completed on time and within budget.