General Notes – Structural – Ground Works


  1. The execution and control testing of earthworks and associated site preparation shall be in accordance with the latest edition of AS3798.
  2. Fill material shall be inorganic, non-perishable material with a sulphur content NOT exceeding 0.5% within 500 mm of concrete structures or masonry unless such elements are protected by impermeable membranes or equivalent means, to be obtained from suitable sources.
  3. General fill shall be well graded with a:
    – particle size 75 mm max.
    – plasticity index 55% max.
  4. Select fill shall have a:
    – particle size 75 mm max.
    – 75 micron sieve: 15% max. (proportion passing)
    – plasticity index 6% max.
    – liquid limit 25% max.
  5. The ground surface shall be prepared before placing fill, ground slabs or load bearing elements. All loose material, debris and organic matter shall be removed. The ground shall be compacted to achieve the required density.
  6. The moisture content shall be adjusted to achieve the required density or moisture content of the fill before compaction.
  7. Fill shall be compacted in layers to the dimensions, levels, grades, and cross sections so that the surface is always self draining.
  8. Fill shall be placed such that the thickness of any layer does not exceed 200mm (loose).
  9. Surfaces shall be finished to required level, grade and shape within the following tolerances:
    – below slabs and loadbearing elements: +0, -25 mm.
    – other ground surfaces: ±50 mm, (the area shall remain free draining and match abutting construction.
  10. The finish shall be as smooth as normally achieved by a scraper blade.
  11. All external areas shall be graded to fall away from buildings with a minimum 1:100 fall.

return to overview