Attachment C - SCG Soil test and Footing report

Vegetation on the construction area (and nearby surrounds) consists of grasses and scattered trees.

The trees are located in the neighbouring allotment on and adjacent the proposed construction site.

The trees are of a height and proximity that could affect the moisture conditions within the proposed construction
site. Refer to the appendices to the rear of this report for guidance on Trees and Construction.

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.

Seepage was encountered during our testing program at 3.0m below ground level on borehole No:1.

This seepage may also cause collapse of excavations. If excavations are not filled with concrete as soon as they
are completed, there may be softening or collapse in the exposed soil profile, which may result in additional clean
out and increased concrete volumes. Temporary shoring or similar maybe required.

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.

Excavatable rock was encountered at the following depths below our test surface level:

                                              Test Site 2 – 1300 mm

Our field testing did not encounter any unexcavatable rock, but we do anticipate stable unexcavatable rock at
relatively shallow depths beneath the base of our test sites.

The potential for water seepage on the sand/rock interface may cause a loss of bearing capacity at this level.
Therefore footings or piers should be increased in depth to pass this interface by a minimum of 150mm should
be increased in depth to found onto the rock.

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 after removing the existing dwelling scraping the site clear of all organic material and debris.
Before basement excavations commence it is anticipated that temporary shoring will be required along the side
boundaries. This could comprise of non-vibrating measures such as contiguous concrete piling. The design of
the temporary retaining walls is to be designed and certified by an RPEQ, in accordance with AS4678:2002 –
Earth Retaining Structures. At the street and rear of the allotment temporary cut batters of 1 to 2 (vertical to
horizontal) and fill batters of 1 to 3 will be stable providing all fill is well compacted and exposed banks are
protected against the potential for stormwater erosion. The earthworks must incorporate a surface spoon drain
at the base and on the high side of the cut. Both drains must have an efficient outflow downslope and clear of
the construction area. Prior to any basement excavation, dilapidation reports of all neighbouring
alottments/dwellings.

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

     SCG Consulting Engineers                                2                                     SCG Ref: 30315(S)