Retroclay Solution & Associated Works

McIver House, located at 297 Fitzgerald Street, Northam, is an asset of the Western Australian State Government. The Department of Housing and Works (DHW) (the Client) is responsible for the facility's management, while Jones Lang LaSalle (JLL) (the Principal) has been appointed by DHW to provide comprehensive property and project management services and is issuing this Request for Tender (RFT) on their behalf. The building has experienced ongoing issues with cracking in non-structural elements, including the intersection of partition walls and bulkheads, and visible differential movement between ceilings and walls. A structural engineering investigation was commissioned to assess the building’s condition and monitor its movement over a twelve-month period. The investigation concluded that a primary cause of the movement is the seasonal shrink-swell cycle of the reactive clay soil beneath the foundations, which responds to changes in moisture content between dry and wet seasons. To address this, a proprietary remediation system known as 'Retroclay' has been specified. The system functions by installing a polyethylene vapour barrier extending from the building's foundation, effectively enlarging its footprint. The area beneath this barrier is then irrigated to raise the moisture content of the clay to its point of maximum swell. The vapour barrier locks in this moisture, creating a stable foundation condition. This approach is designed to mitigate seasonal soil movement and thereby reduce the recurrence of cracking within the building. JLL, on behalf of DHW, is seeking proposals from suitably qualified and experienced contractors to undertake the installation of the Retroclay solution and perform all associated remedial works. The full scope of works is detailed in the engineering documents and specifications.