33522 soil report SCG 28050(S) · MCU18/0001

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.

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.

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.

Where the stiffening beams intersect a perimeter footing, their base must be graded down to the footing base
level, 3 x N12 bars must be cogged into the footing and lapped 500 with the beams trench mesh. Refer to the
structural plans for details.

Where the stiffening beams intersect a blockbase or retaining wall, 3-N12 bars must be dowelled 150mm into the
blockbase and lapped 500 with the beams trench mesh. Refer to the structural plans for details.

A levelling layer under the ground floor slab is to comprise of granular material such as clean sand or crusher
dust compacted in 150mm layers. Either well graded sand or crusher dust can be used.

An approved polyethylene damp proof membrane of 0.2mm (min) thickness is to be placed over the levelling
layer. Laps are to be a minimum of 200mm and be taped. All service penetrations and punctures are to be fully
taped. The membrane is to be extended down the inside face of the perimeter footings and must continue under
any thickenings or stiffening beams.

Drilled Piers Supporting the Slab

Slab piers are required where there is more than 300mm of uncontrolled fill beneath the slab. They are to be
founded at a minimum of 300mm into the NATURAL MEDIUM DENSE SILTY SANDS. Special attention must be paid
to the extra slab thickening required over slab piers as detailed in the structural plans.




     SCG Consulting Engineers                               3                                 SCG Ref: 28050(S)