Completion year 2018
Rottnest Island Roof Structure & Wall Remediation Program 2013-2018
This project involved the modification and reconstruction of roof and wall structures to over 337 public buildings across the island over a five year, state government funded program. The project also included the investigation, reporting, documentation and ultimately the structural restoration of 29 of WA’s most historically significant heritage-listed buildings in liaison with a heritage architect and Heritage WA.
The program priorities were to preserve historical construction fabric whilst achieving ongoing public safety, building durability and building code compliance. WGE set up a temporary office on the island completing the restoration program over 3-4 months each year for six years.
In some cases, original 100-year-old timber roof shingles in conjunction with a sealed lime slurry ceiling structure required the development of a bespoke and sensitive approach in order to achieve adequate tie down and roof strengthening.
The variety in shortcomings, building types and issues encountered, along with the logistics of the island location required a flexible, sensitive and often innovative mindset. WGE provided resident structural engineering, site supervision and contract superintendence services.
Rottnest Island WWII Defence Establishment
The heritage-listed Defence Establishment was an Army base in World War II, and includes bunkers and gun emplacements, plotting rooms, observational towers, magazine and ammunition stores.
The buildings were in a poor state of repair and accessible to public, so preservation and public safety were key considerations for this project. WGE’s structural team were appointed as heritage advisor, project engineers and contract superintendent.
To preserve and refurbish the building fabric, with minimal intervention approach (consistent with the Burra charter – guidance for heritage works) a program of steel treatment, concrete repair, glass replacement and masonry refurbishment was carried out.
A set of big steel doors that had seized up were reinstated with a coating applied to the steel to preserve it while maintaining the original painted signage. Significant concrete refurbishment was required as crumbling concrete and rusting steel reinforcement was a risk to public safety. The team undertook concrete refurbishment by priming the steel reinforcement, repairing mortar and applying chloride resistant migrating protection.
The success of the project was achieved through a sensitive engineering approach balanced with the need for safety and risk reduction. WGE’s role required specific and extensive product knowledge – to understand interactions between the different solutions and products that were utilised.
The project was awarded the 2014 Heritage Award for Outstanding Conservation of a Non-Residential Place for the Rottnest Island WWII Defence Establishment.