One of the first questions clients ask when planning a renovation or new build is: “What will it cost?” We carefully work through budgets, balance priorities, and aim to deliver the best outcome for the investment. But one element often overlooked is the contingency allowance — money set aside for the unexpected.
A recent project reminded us just how important that buffer can be.
An Unexpected Find Beneath the Garden
After completing a significant addition and alteration to a home, the next step was landscaping the modest front garden. The design was simple, and works began smoothly — until the landscaper, while demolishing old paving near the entry portico, struck something unusual.
It turned out to be a two-by-two metre void hidden beneath the surface. Work stopped immediately, and an engineer was called in. At first, it seemed localised, but as excavation continued, it became clear the void stretched across much of the front yard. What emerged was an arched double-brick structure, large enough to spark questions — was it a war bunker? A wine cellar?
Once again, works were paused. The structural engineer designed a permanent solution, which included installing a large concrete beam across half the yard to safely support a pathway above.
The Budget Impact
This unforeseen discovery added more than 20% to the original landscaping budget. For many projects, such a cost could have caused major delays or compromises.
In this case, the clients had wisely retained their contingency funds rather than spending them on extras. That foresight meant the works continued without financial stress, and the garden was completed as intended.
Solving the Mystery
Curiosity led us to the State Library archives, where old drawings revealed the underground structure was not a bunker or cellar at all — but a water tank from the grand homestead that once stood on the site.
A forgotten piece of history, hidden beneath the surface, and a perfect example of why contingency exists.
Why Contingency Matters
In construction, surprises are not a matter of if but when. Hidden ground conditions, outdated services, or structural weaknesses can appear without warning.
A contingency allowance — typically around 5–10% of the construction budget — gives you the flexibility to respond to these challenges without compromising the quality or completion of your project. It allows you to make considered decisions under pressure, rather than rushed compromises driven by cost.
Final Thought
That hidden water tank could easily have brought the landscaping works to a halt. Instead, with contingency planning in place, the project was completed smoothly — and the clients now have both a beautiful garden and a remarkable story to share.
A contingency is not wasted money. It’s your safeguard, your peace of mind, and often the difference between a project stalling and a project succeeding.
