Reference Document - MCU25 0060 (As Published)

1.           Introduction
This report details the results of a geotechnical investigation undertaken for a proposed residential
development at 22/512 David Low Way, residing on Marcus Dunes Court within The Dunes estate at
Castaways Beach. The investigation was performed by Tectonic for Kylie Collum, generally in accordance
with our Proposal P25025-Rev0, dated 29 January 2025. Shaun Lockyer Architects (SLa) are the design
consultants and project managers for the build.
The investigation comprised drilling of boreholes at three locations across accessible areas of the
development footprint. This report summarises the results of the investigation and provides
geotechnical recommendations regarding earthworks and footings, together with advice for temporary
and permanent basement retention.
In summary, subject to the implementation of the recommendations made herein, it is assessed that
there would be a Low Risk of slope instability affecting the proposed development in accordance with
the Australian Geomechanics Society Guidelines for Landslide Risk Management, dated March 2007 (AGS
2007).



2.           Proposed Development
Architectural drawings were supplied to us with the project brief (Ref. SLa, Project No. 0448, Dwg. No.
000.00 to 400.07, Rev E & F, most recently dated 3 April 2025). Based on the drawings provided, it is
understood that the proposed residence will consist of a three level structure:
▪    The lower level would be ‘dug in’ to the ground completely on the upslope side, and ‘daylighting’
     downslope to the east. The lower level footprint would be over most of the available area for
     building within the site. An in-ground pool would also be located towards the eastern site boundary,
     with the lip equitable with the lower level of the house.
▪    The main central living level would be present above, incorporating a garage to the west and
     cross-over from the Marcus Dunes Court road frontage.
▪    The uppermost level would be limited in area, including enclosed living spaces to the west, and an
     area of open roof terrace to the east.
▪    A landscaped batter slope would extend down from the north-western corner of the block towards
     the main pedestrian and vehicular accesses.
Bulk excavations for the development will be in the order of up to about 3 m depth below ground level
(locally up to 3.5 m) to site to the lower level of the house, and up to about 2 m depth for the in-ground
pool. With the site works proposed, filling is expected to be minimal, however could range up to about
1 m in height and 0.5 m height for localised levelling or landscaping purposes over the remainder of the
site.




Proposed Residential Development
25 August 2025 | 25038-001-Rev0                                                                              1