Engineered Rebuild – Charlestown
Restoring stability and structural confidence after a dual wall collapse
The Situation
When two retaining walls collapsed in succession at this Charlestown property, the complexity escalated quickly. Our client owned the upper wall that was retaining a pool and elevated deck, while the lower wall became the responsibility of an insurer.
Before we could begin our client’s rebuild, the lower wall required completion. With the insurer unable to source contractors to finish their component, we stepped in to complete landscaping works on their behalf so the project could progress.
Adding further pressure, the house was in the cooling-off phase of a sale when the wall failed. The new owners chose to proceed at a renegotiated price, but the original owners were required to cover the cost of rebuilding the wall. With legal, financial and access considerations involved, clear communication and staged delivery were essential.
The Main Issues
- Two walls collapsing in sequence
- A pool and deck needing to be safely retained
- Insurer unable to source contractors
- Property sale underway with obligations spanning old and new owners
- Multiple neighbours requiring access
- Engineers, certifiers and specialist contractors all needing coordinated sched
What Was Most Important to the Clients
The priority was to build a wall that was structurally sound, fully compliant and engineered to prevent any repeat failure. They needed confidence that the new wall would safely retain the pool and deck long term. After months of insurer and council negotiations, they were looking for a methodical, reliable delivery process that removed uncertainty.
Balancing Technical Demands with Practical Delivery
A full engineering design was completed, including boundary and geotechnical surveys and formal council approvals.
The wall was constructed from silt from blockwork reinforced with a network of entwined steel. To stabilise the structure, specialist screw piers were drilled and driven deep into the embankment. Each pier was extended as needed until it reached the required soil density and depth to lock the structure into stable ground.
It was a highly technical design, but also one that needed to be built with precision and patience.
Managing Complexity and Multiple Stakeholders
- Engineers
- Council certifiers
- Specialist screw pier contractors
- The original owners (covering costs)
- The new owners (providing access)
- Two neighbours needing yard access
- The insurance company responsible for the lower wall
Ensuring Compliance and Engineering Integrity
- The engineer remained available throughout the build for clarification.
- Certifiers attended site at predetermined intervals to inspect reinforcement, footings, piers and blockwork.
Client Response
This project wasn’t one filled with excitement. It was a long, draining experience involving insurers, lawyers and approvals before construction could even begin.
The overwhelming response once completed was relief. Relief that it was compliant, safe and finally finished.
Despite the difficult circumstances, the clients appreciated the way the project was managed and ultimately engaged us again to landscape their new property once they had financially recovered from the rebuild.
What Future Clients Should Know About Engineered Rebuilds
- Insurance does not always cover retaining wall failures. Never assume it will.
- Rebuilds are almost always more complex than new builds. Engineers will design conservatively to ensure failures do not repeat.
- These projects are expensive and time-consuming. Surveys, engineering, approvals and staged inspections all add to timelines.
- Prevention is the best investment. Do not cut corners on retaining walls. Future you may pay for it many times over.
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