Appendix B - Geotechnical Investigation Report

6     COMMENTS AND RECOMMENDATIONS

6.1    Site Layout and Development Details
Based on a review of the provided information and additional information provided by Morrison
Architecture, we understand that the existing shed and car port over the south-eastern portion of the site
will remain and a new one and two storey residence will be constructed to the north of the existing shed.
The residence will extend over the existing slope and the structure will be supported by steel columns and
the suspended floors will be timber framed. An effluent disposal system is proposed over the south-western
portion of the site. The proposed finished floor reduced levels (RL’s) of the Lower and Ground Floor Levels
will be RL10.4m and RL13.2m, respectively. A limited amount of localised excavation at the southern
(upslope) end of the proposed lower level in the order of a maximum of 2.2m will be required to achieve the
design surface levels. At a later date, a southern extension including an additional bedroom and new car
port is proposed; the bedroom will be provided with a suspended timber floor and the car port will be provide
with an on ground concrete slab.



6.2    Site Classification
The ASI “Soil Test Report” has identified the site as being Class P in accordance with AS2870-2011 due to the
presence of uncontrolled fill, “poor” allowable bearing pressure of the upper soil profile and the presence of
trees, some of which will be removed. We concur with the Class P site classification.



6.3    Demolition and Excavation

6.3.1 Dilapidation Surveys
Prior to the commencement of excavation, detailed dilapidation reports should be compiled on the
neighbouring properties to the east and west. In addition, Council may require that dilapidation surveys
report be completed on the Council assets lining the street frontage, i.e. the roadway and kerb and gutter.
The property owners should be asked to confirm that the reports present a fair record of existing conditions
as the reports may assist the client in defending themselves from unfair damage claims.



6.3.2 Demolition and Excavation Methods
The excavation recommendations provided below should be complemented by reference to the current Safe
Work Australia Code of Practice ‘Excavation Work’.

The outline of the proposed Ground Floor level is indicated on the attached Figure 2. To achieve design
surface levels excavations are expected to extend to a maximum depth of about 1m below existing levels.
The excavations will remove the overgrown rock retaining wall indicated by the survey plan over the eastern
end of the steep central portion of the site. The rock wall may extend into the neighbouring site.




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