Client Name : Mr Client Address : 20 Sample Street in 6026 Kingsley, WA Our Reference : 01548 Site Investigation Report Property : 20 Sample Street in 6026 Kingsley, WA Inspection Date : 27.04.2011 Weather Conditions : Sunny Inspector : Peter Hopfinger: Structural Engineer/ Building Surveyor Report Purpose : As requested, a site investigation was carried out at the above address and date. The purpose of the inspection was to investigate and report any cracks noted in common areas of the property 1
Table of Contents Description... 2 Subsurface Conditions... 2 Observations... 2 Conclusion &Recommendation... 3 References... 3 Topography....4 2
General Description of the Property and Site The building is a single residence. The front of the house is facing west. The design of the property is brick and tile. The bricked house is approximately 30 years old with infill slab sitting on concrete footings. The site classification is Class A (no ground movement) SUBSURFACE CONDITIONS The review of the history maps indicates that the site was mostly residential in nature. The study area on the date of field investigation consisted of different elevations is relatively level. The topography to the south and west of the site slopes down to the south and west at approximately 2 to 4. It is known in this area that no ground water is to be encountered within the depths of 8m Observations: Diagonal and vertical cracking varying in width between 0.8 and 4 mm was observed to the brick wall to the front of the house. The cracks were approximately 1800-2400 mm long. A tree was growing at corner adjacent to the window. The tree roots of the tree may have caused the problem but undermining of the footing by other causes may also have contributed or been the sole cause. This settlement crack probably occurred during initial footing settlement. Notice that it is wider at the top than the bottom of the crack. This suggests that the footing to the left of the crack has moved downwards; with further downwards movement as we move further from the crack itself 3
The lintel above the subfloor entry point is also badly corroded and deformed. This appears to be due to moisture accumulation on the steel. As steel corrodes, it expands. The expansion of the steel has caused cracking in the masonry below the top corners of the windows. 4
Replacement of steel lintels and localized masonry replacement is likely to be necessary within the next few years. Although this is not a major structural concern, ongoing cracked of the masonry and the need for periodic repairs should be anticipated Conclusion & Recommendations If the crack is not changing in width and length, maybe the footing of the wall has stabilized and can be repaired by a technique known as metal stitching. Here lengths of metal rod (rebar) are fixed across the crack with epoxy before the crack is filled. Info: http://www.helifix.com.au/crack_stitching.html If the crack is changing in width than the footing of this wall to the left hand side (seen from the front) will require underpinning and the tree may be removed to stop further settlement. The lintel over the subfloor access point requires replacement and the brickwork should then be repaired. In my opinion the cracking to those wall has not compromised the structural integrity where the building would be considered unsafe. The external cracking is classified under the Australian Standard AS2870- Residential slabs and footings Table C1- Damage Category 3 - moderate. Once the footing is underpinned or the source of the cracking has been removed then the cracking can be repaired. References: 5
6 Inspector Group. Level 1-100 Havelock Street West Perth, WA Phone: 1300 360 864
7 Inspector Group. Level 1-100 Havelock Street West Perth, WA Phone: 1300 360 864
8 Inspector Group. Level 1-100 Havelock Street West Perth, WA Phone: 1300 360 864
Topography http://www.joondalup.wa.gov.au/explore/mappingonline.aspx http://www.joondalup.wa.gov.au/live/environment/biodiversity/plantinglocalnativeplants.as px 9