Scg 25335(S) · OPW16/0105

We recommend using a footing system as per the attached plans and details on the prepared construction pad.

For the design to be valid the cut/fill line must be in the position shown on our footing plan. Any variation must
be brought to the attention of this office before continuing work.

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.

Where site drainage and landscaping does not conform to the specifications of AS 2870-2011 and CSIRO
Information Service Sheet BTF-18 significant damage to the building can be expected. A single copy of this
document is issued with the original issue of this report. Please consult your builder or contact this office to
obtain a copy.

The builder must ensure the stability of neighbouring/existing structures is maintained through not
undermining their foundations. This is achieved via restricting any excavations to above a line
radiating downwards at an angle of 1 in 1.5 (vertical to horizontal) from the base of the
foundation/structure to be protected.

Any new vegetation including trees planted adjacent the structure should follow the recommendations
appended to this report.


6     FOOTING AND SLAB SPECIFICATIONS

Footing Details

All footings must be founded a minimum of 300mm into the NATURAL MEDIUM DENSE SILTY SANDS (shown
shaded on the attached log sections). Dimensions and reinforcement requirements are detailed on the
structural plans and details.

Where the NATURAL MEDIUM DENSE SILTY SANDS is deep or is covered by the introduction of or the presence of
existing fill, the footings are to be increased in depth to reach this level. Alternatively the footings can be
supported on piers founded into the foundation material or deeper as required to obtain the required strength.
Refer to the structural plans for details.

Where unexcavatable rock is encountered at depths shallower than the founding level, the strip footing (non-
retaining) depth may be reduced accordingly to a minimum of 150mm providing the footing is founded a
minimum of 100mm into un-weathered or un-disturbed rock. Additional reinforcement shall be provided in the
footing at the rock/soil interface. Please contact SCG Consulting Engineers to obtain an appropriate detail.

Drilled Piers Supporting the Footings

Where the NATURAL MEDIUM DENSE SILTY SANDS is deep or to be covered by fill the footings can be supported
on drilled concrete filled piers founded at a minimum of 300mm into the NATURAL MEDIUM DENSE SILTY SANDS.
The size and spacing of these piers is nominated on the structural plans.

Where drilling piers is not practical the footings could be supported on steel screw piers.

Where unexcavatable rock is encountered at depths shallower the founding level the piers shall be augered a
minimum of 100mm into un-weathered or un-disturbed rock.

Floor Slab Details

The thickness and reinforcement for slabs on ground are shown on the structural plans.

Ground slabs may require thickenings or stiffening beams incorporated in their construction. It may be
advantageous to excavate them at the same time as the perimeter footings. Refer to the structural plans for
the locations and extent of these.


    SCG Consulting Engineers                               3                                    SCG Ref: 25335(S)