Excavation in Bateau Bay
On Bateau Bay's sandy coastal side, expect a dig to need its sides supported. The state soil survey maps that part of the suburb as the Norah Head landscape, windblown sand perched on bedrock from Bateau Bay to The Entrance, and warns that where excavation goes into the loose sands, slumping can occur and shoring of foundations and batters may be required.
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Excavation around Bateau Bay
The survey rates the foundation hazard there as low to moderate, as long as the sands are compacted adequately, and notes that swampy swales were often reshaped and filled when the land was developed. It describes sand that is stable when compacted adequately and liable to slump when it is dug while loose. For a pool or a footing trench that points to benched, battered or shored sides rather than a straight-walled hole, and SafeWork's excavation code says shoring should be designed for the site by a competent person.
Most of the rest of Bateau Bay's housing is on different ground: the Woodburys Bridge landscape on Patonga Claystone, whose subsoil the survey describes as highly plastic, with moderate to high shrink-swell and low wet bearing strength. Council's geotechnical matrix sets its lowest slope thresholds for Patonga Claystone, putting a lot in the category where a development application needs a geotechnical report once the slope passes about 6 degrees. Which side of the suburb a block is on changes the conversation with the provider.
Permits and Central Coast Council rules
Parts of Bateau Bay's low land are in Council's flood planning area, under the Tuggerah Lakes southern catchments study and the Killarney Vale and Long Jetty plan. Council's controls for the former Wyong area don't permit filling in flood storage unless an adopted floodplain plan allows it, and in flood planning precinct 2 filling needs a qualified engineer's report approved by Council, which matters for what happens to soil from a dig.
Source: Central Coast DCP 2022 Chapter 3.1 Part B, 3.1.5.3(a), and Chapter 3.7; NSW soil landscape reports for the Norah Head and Woodburys Bridge landscapes — confirm current requirements with Central Coast Council.
Our Bateau Bay service area
From Bateau Bay, an enquiry is referred to an independent local provider, who gets in touch to see the ground and quote.
See all Excavation on the Central Coast. We also work in Wamberal, down the coast, and Berkeley Vale, inland.
Call (02) 4326 8289Last reviewed · Updated · First published