35484 Approved Plans Ba · MCU21/0222.01

Vegetation on the construction area (and nearby surrounds) consists of grasses.
The trees are located adjacent the proposed construction site.

The existing surface drainage is good and sub-surface drainage is good.

4 FINDINGS
The soil profiles encountered are shown on the attached borelog sections.
No water table was encountered during our testing program.

The sandy soils encountered are susceptible to collapse when unconfined. This may effect excavations and
result in additional earthworks and increased concrete volumes. Temporary shoring or Forma-Tube may be
required to retain the sands prior to concreting.

The samples classified on-site were assessed as having negligible plasticity, therefore laboratory testing was
considered unnecessary.

We have assessed the expected differential movement of the soil profiles encountered to be the equivalent of a
site with a Ys of less than 20mm.

The following foundation material will provide a safe bearing capacity (100 kPa) for buildings within the scope of
AS 2870-2011 and is shown shaded on the attached logs;

FOUNDATION MATERIAL - NATURAL MEDIUM DENSE SILTY SAND

5 SITE PREPARATION DETAILS

We recommend the structure be supported on steel screw piers designed and installed by a specialist contractor
to achieve the loads nominated on the structural plans.

For the basement construction it is anticipated that battering is not likely to be suitable, bulk excavation will
therefore require positive support such as contiguous concrete piling. The design and certification of temporary
retention walls should be specifically designed and installed by a specialist Contractor and should consider the
protection of all neighbouring structures from movement and vibration damage. It is strongly recommended a
delapidation report of all neighbouring structures is undertaken prior to works commencing.

Where a retaining wall is required, a cut batter of 1 to 2 (vertical to horizontal) in the sand profile taken from the
base of the proposed wall should be excavated. Backpropping to retaining walls should be provided throughout
the backfilling and compaction process. These earthworks must incorporate shallow surface spoon drains at the
base and along the high side of the cut. Drains must have an efficient outflow down-slope and clear of the
construction area. The exposed face should also be protected against the potential for stormwater erosion.
Should these recommendations be un-achievable the builder should seek guidance from this office on temporary
shoring, benching or other suitable techniques.

Areas where existing structures or trees are removed shall be backfilled with engineer approved fill material
compacted to achieve a minimum relative field density of 98% and be in accordance with AS2870-2011. Where
trees are removed prior to construction the moisture conditions of the soils must be allowed to normalise across
the site prior to commencing foundation preparations.

Any loose or soft material uncovered in the site preparation shall be removed and replaced with approved fill
material compacted in accordance with AS2870-2011, or alternative measures to be provided by the engineer.

We recommend using a footing system as per the attached plans and details on the prepared construction pad.
Site drainage during construction is important. Stormwater run-off should be diverted away from any foundation
excavations and not be able to pond within 5.0m of the building footprint. Temporary piping or spoon drains or
other practical methods should be used. Please refer to the Appendices to the rear of this report for drainage
management.

The final surface profile should fall away from any slab on ground for a minimum of 1.5m at a grade of no less
than 1 in 20. Refer to appendices for drainage recommendations,

SCG Consulting Engineers 2 SCG Ref: 32027(S)