a sample building soil report:
CIVIL & SOIL PTY LTD acn076191056 abn58076191056
0419314545 buildingsoiltest@gmail.com
site somehere near Melbourne date 9December2025 report number 912225
BUILDING SOIL TEST REPORT
approximate site sketch (m)
borelogs (mm) (verify during construction)
0-500 firm silt,grey,moist
500-1500 stiff clay,tan,moist
1500 end
B2
0-500 firm silt,grey,moist
500-1000 stiff clay,tan,moist
1000 end
This report is for articulated masonry or clad frame, on footings or slab.
The site classification is classM if this report is adhered to.
All masonry should be articulated at least every 5m, with horizontal sliding ties.
The ys is 40mm on natural soil.
The generic information in this report shall apply where relevant.
Footings, edge beams and beams supporting masonry should be founded at least 100mm in natural stiff clay or deeper, or to rock, where the allowable bearing pressure is 150kPa. The minimum founding depth is 600mm (400mm to rock, less with engineer design) for footings, 200mm (zero to rock) for stiffened raft slab beams, zero for waffle raft slab beams. Any slab area should be stripped of vegetation. Any fill should be controlled or design as suspended. The allowable bearing pressure under the slab is at least 50kPa, unless suspended. Founding at least 200mm in natural stiff clay at a minimum founding depth of 1000mm (400mm to rock), will achieve an allowable bearing pressure of 200kPa.
INFORMATION
This is generic information for a building soil test report based on AS2870-2011 and experience. When preparing the foundations, small amounts of sand disturbed during excavation may need to be recompacted as controlled fill and treated as natural. Rock is considered natural bedrock or natural rock securely founded in the natural founding layer. Technically rock can be hard soil. With engineer design, founding depths may be reduced where founding on rock, even levelling pads are permitted. Controlled fill should comply with AS2870 section 6.4.2. Granular fill like sand, gravel or crushed rock should be well compacted in maximum 300mm layers. Non-granular should be well compacted in maximum 150mm layers. Do not use clay fill for classA or classS. The maximum depth before suspended design is required is 800mm for granular fill, and 400mm for non-granular fill. You should remove poor quality fill and paving. Class P is for problem sites. Soft, unstable soil or abnormal moisture conditions can cause problems. Clay soils swell and shrink with moisture changes. The surface maximum vertical surface movement for natural soil is ys(mm). This is normally due to the seasons. The ys(mm) values are classA=0mm, classS≤20mm, classM≤40mm, classH1≤60mm, classH2≤75mm, and classE>75mm. Abnormal moisture conditions may cause these to be exceeded on clay sites. Abnormal moisture conditions are due to previous structures and paving, or trees closer than recommended, poor drainage, flooding, drought, etc. The rule of thumb is that trees should be a at least 75% the mature height of the tree away from the building on clay sites, but trees can physically push the foundations even on classA sites. Articulation makes masonry flexible, reinforcement strengthens masonry. It is recommended all masonry be articulated at least every 5m or reinforced, especially near trees, at extensions, and changes of such things as: height, loading, level, founding material, footing type, or depth. Articulation is provided by vertical construction joints. These should be placed at: door corners, window corners, full height doors, full height windows, and clad sections. Horizontal sliding ties are recommended to reduce lateral movements. Methods to reduce damage to masonry structures include remove trees too close, reinforced brickwork, change to clad frame which is more flexible, increase founding depth directly or indirectly by pier or pile, found on rock, or help moisture to stabilize. The standard angle of repose is 45° for clay, and 30° for sand, there is none for silt, fill or rock. The angle of repose is for temporary excavations, easements and near fill. Trenches below the angle of repose should be filled with stabilised sand, mortar or concrete. Standard designs have limitations like 30m in length and a maximum of two storey height. There are no standard designs for classE or classP.
Bill Bolwell BE(Civil) MIE/CPEng/Au6701 PE0003352
this report is copyright, unpaid reports will be cancelled