Baulch v Bogatai

[2016] NSWLEC 1269

Land and Environment Court

New South Wales

Medium Neutral Citation:	Baulch v Bogatai & anor [2016] NSWLEC 1269
Hearing dates:	20 June 2016
Date of orders:	28 June 2016
Decision date:	28 June 2016
Jurisdiction:	Class 2
Before:	Fakes C
Decision:	The application is dismissed.
Catchwords:	TREES [NEIGHBOURS] Damage; injury; range of possible causes; presence of roots not conclusive
Legislation Cited:	Trees (Disputes Between Neighbours) Act 2006 Land and Environment Court Act 1979 Uniform Civil Procedure Act 2005 Land and Environment Court Rules 2007
Cases Cited:	Robson v Leischke [2008] NSWLEC 152; (2008) LGERA 280 Smith & Hannaford v Zhang & Zhou [2011] NSWLEC 29
Category:	Principal judgment
Parties:	Ms Wendy Baulch (Applicant) Mr Sacha Bogatai and Ms Rachael Poulden (Respondents)
Representation:	Applicant: Ms W Baulch (Litigant in person) Respondents: Mr C Poulden (Solicitor)   Solicitors: Respondents: Beilby Poulden Costello
File Number(s):	150148 of 2016

Judgment

1. COMMISSIONER: The applicant has applied under s7 Part 2 of the Trees (Disputes Between Neighbours) Act 2006 (Trees Act) for orders seeking the replacement of the brick veneer wall at the rear of her dwelling at the respondents’ expense. The orders are sought on the applicant’s contention that trees that were growing on the respondents’ property caused the wall to crack. The applicant is also concerned that failure of the wall could cause injury to anyone on the respondents’ property.

Relevant background and written evidence

2. The parties’ properties back on to one another. The applicant’s property is upslope and to the north of the respondents’ property.

3. The applicant’s dwelling is a part one, part two storey cottage in Balmain (described as #3). The outer face of the rear brick wall of the dwelling is constructed on the rear boundary of the applicant’s property and adjoins the majority of the rear of the respondents’ property (described as #8) and part of the adjoining property to the east (#10). The rear wall of the adjoining property to the west of the applicant’s dwelling (#1) forms the remaining section of the rear boundary of the respondents’ property.

4. In September 2015 the respondents advised the applicant of a crack in the brick wall and sent her a photograph of it.

MCS report

5. In early October 2015 the applicant contacted her insurance company; subsequently, the property was inspected on 6 October 2015 by Mr Paul Nicholas, a Civil Engineer from MCS Group (MCS Report). He states in the preamble to his report at paragraph [5] that he was informed that the applicant’s Building Inspection Report did not include an assessment of the rear wall as neighbouring properties had not been accessed by the inspector. Mr Nicholas visually inspected the internal condition of the ground floor bedroom at the rear of the dwelling and inspected the wall and its surroundings from the respondents’ property. He notes that there is no cracking or distortion of the plasterboard of the room. Mr Nicholas also notes the presence of two large palm trees and what he describes as a mature, double-trunked Jacaranda, and other shrubs, growing in a raised planter box constructed across the rear of the respondents’ courtyard in front of the wall. He describes the stepped crack, up to 25mm at its widest at the top of the wall extending down to finer vertical crack almost directly in line with the western trunk of the ‘Jacaranda’ tree. Photographs in the report also show ivy on the western part of the wall.

6. Mr Nicholas cites a CSIRO document – Foundation Maintenance and Footing Performance: A Homeowner’s Guide and concludes that the trees are the probable cause of the failure in two main ways: by roots growing under and propping the footing, and by the action of roots in the vicinity of the footings absorbing water from the soil thus causing shrinkage or subsidence. Mr Nicholas states, without citing a reference that “typical soils in the Sydney/ Parramatta basin are of a reactive clay type and are very prone to shrinkage or swelling under differential moisture levels”. He considers that further settling of the wall foundations may occur. Mr Nicholas recommends the immediate removal of the trees and shrubs in the planter box, monitoring as soil moisture levels stabilise as some reversal of the wall rotation may ensue, and the appointment of a Geotechnical Engineer to design and oversee any remediation works.

7. In late October 2015, the respondents lodged a Development Application with Leichhardt Council seeking consent for the removal of the two palms and a China Doll tree (Radermachera sinica) [the ‘Jacaranda identified in the MCS Report].

Information – Ms Kerry Hunt, Leichhardt Council

8. On 26 November 2015 council’s Co-ordinator Building Assessment and Certification Team, Ms Kerry Hunt, inspected the respondents’ property and examined the applicant’s plans and reports submitted on behalf of the insurance company. In correspondence included in the respondents’ bundle of documents (Exhibit 1), Ms Hunt provides details of previous approvals and other relevant matters. The wall is described as brick veneer and appears to have been constructed as part of a 1982 Building Application (BA). Ms Hunt notes that plans for the BA show a sectional detail of the wall on the boundary with strip footings and a timber bearer and joist floor. This was constructed and signed off. A 2001 application shows that the existing brick wall was to be kept, reduced in height for rear boundary setbacks, and the internal timber floor replaced with a concrete slab. The internal timber frame for the rear bedroom and bathroom was constructed and the roof pitched from the timber frame. The rear brick wall is not load-bearing and there should be brick ties holding the wall to the timber frame. There is a shared sewer which runs under and parallel to the rear boundary.

9. Ms Hunt states that the adjoining property at #10 had extensive excavations at the rear of the property in 1993; the ground level at #10 is some 1.2m below the ground level of #8. Retaining walls were constructed along the rear boundary of that property, part of which adjoins the applicant’s property.

10. Regarding the cracked wall, Ms Hunt recommends the weatherproofing of the crack, cleaning of gutters to ensure no overflow down the wall, removal of the trees and planter box, further investigation of the underlying foundations and footings by a structural engineer. She notes that the footings appear to have failed causing a shear drop in the brickwork and that the absence of algal growth in the crack indicates that the crack may be quite recent.

11. Ms Hunt also provides a number of factors that may have contributed to the wall failure including: location of the trees near the wall in a built up garden bed with no weep holes; inadequate bearing of foundation material for the existing 1982 wall and changes made to ground levels on both #8 and #10 which may have undermined the footings; impact of the concrete slab on the existing wall structure when the bearers and joists were removed as part of the 2001 building works; and the underlying soils are likely to be sandstone based and not reactive clays as stated in the MCS Report.

12. Council granted consent on 21 December 2015 and the trees and the planter box were removed in January 2016. The stumps were ground and soil replaced. The planter box has not been reinstated.

Rollo report

13. On 21 January and again on 10 February 2016, the applicant’s structural engineer, Mr Richard Rollo, inspected the damage to the rear wall. The purpose being to determine the nature and cause of the problem and to recommend measures to eliminate or minimise further damage. Mr Rollo was provided with the MCS Report and Ms Hunt’s document. Mr Rollo’s report is dated 8 April 2016 (Exhibit B).

14. At the time of Mr Rollo’s first inspection, the garden bed containing the stumps of the removed trees was still in place. Mr Rollo recommended that the garden bed be removed down to the level of the rest of the rear courtyard and that two test pits be dug to establish the depth and nature of the wall footing. On his return on 10 February, he found that a trench had been dug along the whole length of the wall and the wall had been hosed off. He observed that this action, while well-intentioned, may not be ideal in the circumstances.

15. Mr Rollo observed the wall to be founded on a concrete footing approximately 300mm deep and estimated to be about 300-400mm wide. The soil beneath the footing appeared to be a mixture of residual sandy soil with traces of clay and gravel. He observed large roots of the China Doll tree under and alongside the footing. Mr Rollo recommended that more of the stump be removed and that the trench be backfilled and compacted.

16. In his report Mr Rollo makes a number of observations and comments including:

• The footing appears to have performed satisfactorily since 1982 which suggests there was no fundamental flaw in its design or construction.

• The crack appears recent (no algal growth), is virtually hairline at its base and increases in width to 20-25mm at the top of the wall.

• The stepped crack (and its lateral displacement) suggests that the wall has ‘pivoted’ about the vicinity of the China Doll tree stump.

• The brickwork slopes significantly downwards to the west of the stump and gradually to the east of the stump which suggests either the footings on both sides of the failed or settled at the same time or that the wall has risen in the vicinity of the stump. The latter scenario is more likely.

• Roots of the China Doll tree were observed against the underside of the exposed footing; palm roots unlikely to have caused any problems.

• The brick boundary wall in the southeast corner of #1 is in very poor condition with a sub-standard footing but is unlikely to have been a factor in causing the damage to #3.

• The brick retaining wall between #8 and #10 leans towards #10 and may not have been engineered as a retaining wall but in any event, is unlikely to be a cause of the damage to #3.

• There is a Sydney Water sewer pipe in a former easement along the shared rear boundaries of all properties in the two adjoining streets. The existing footing does not show any signs of concrete piers beneath the footing which might be expected where a footing is constructed adjacent to a Sydney Water sewer. It is possible that the pipe is some meters below or the footing is out of the zone of influence. However, the presence of the pipe is unlikely to be a cause of the damage.

17. Photographs in the report show four large diameter roots [estimated to be about 75-100mm in diameter] in the north-eastern corner of the respondents’ property in close proximity to or under the footing. Mr Rollo states that whilst he is not an arborist, it is his understanding that, as they expand, primary roots of trees can cause the heaving or lifting of footings that may be above them. He also discusses the interaction of roots and “shrink – swell” clays [reactive clays]. Mr Rollo notes that the addition of moisture to reactive soils from sources such as damaged gutters, broken pipes, and other local drainage issues, could also cause heaving of footings. He considers that most of the suburb of Balmain is not underlain by reactive clay but rather the sub soils are likely to be residual clayey sandy soils derived from the weathering of the underlying sandstone. Mr Rollo does not discuss the other possible causes of failure identified by Ms Hunt in her report.

18. Mr Rollo concludes that the wall has been damaged by tree roots from the China Doll tree. The primary crack in the wall emanates from the original location of the tree; significantly sized roots were noted under the footing at the stump. Given the outwards rotation of the wall and uncertainty as to how it may be secured to the internal timber frame, Mr Rollo suggests that a worst case scenario could see the failure of the wall into the respondents’ property. He suggests a number of remedial measures including an option to retain the concrete footing and the first 800mm of brick veneer and replace the upper portion with a lightweight timber framed and insulated wall clad with fibre cement sheeting/ planks or similar. Mr Rollo outlines other complications that may arise depending upon the exact depth and location of the sewer and other aspects of the dwelling.

Barry report 11 March 2016

19. The respondents engaged Mr Gerard Barry, Consulting Engineer, to inspect the wall and prepare a report. Mr Barry inspected the wall on 22 and 25 February and 6 March 2016 and prepared a report dated 11 March 2016 (Exhibit 2). Mr Barry was provided with the MSC report, Ms Hunt’s information, a survey and other documentation noted in his report.

20. Mr Barry notes that the wall is 7 m long and the concrete footing is between 220-250mm deep. He extrapolates the width of the footing to be about 500-600mm.

21. In section 3.3 of his report, Mr Barry states that the wall appears to have been constructed in 1982 in accordance with drawings produced by the architects on the project. He states that the notation on drawing 8213-2A adjacent to the footing reads: “110 brickwork with 230 engaged piers at max 1800 cts (centres) on 300(mm) x 600(mm) strip footings with F8TM top and bottom on R10 ties at 900 cts”.

22. In regards to the works on #10, Mr Barry assumes that any excavation below the footing of the applicant’s wall involved underpinning of the wall. He notes that the assumed underpinning is covered by a 230mm thick, and apparently structurally sound, brick retaining wall at the base of the applicant’s wall. Mr Barry opines that that section of the wall is likely to be founded on very stiff sandy/clayey soils or better, such as sandstone rock.

23. It appears from the photographs in Mr Barry’s report that at the time of his first inspection, the trench had been backfilled after the grinding of the stumps. In order to investigate possible causes of the damage, Mr Barry dug three test holes – one at each end and one in the middle, to a depth of about 500-600mm below the top of the footing. He notes that the soil at the western end near #1 was very soft, saturated reddish brown sandy/clayey soil; in the middle and eastern holes was a layer of topsoil over soft light brown sandy/clayey soil. In his opinion as the wall footing is set above what he considers to be the natural ground level, as established by the level of paving in the respondents’ courtyard, and thus within the topsoil zone and not into reasonable and uniform bearing material, the footing is more vulnerable to damage from seepage, drainage water, and root systems of trees.

24. In paragraph [4.2] of his report, Mr Barry lists other factors affecting the applicant’s wall including:

• Absence of vertical expansion joints in the wall;

• No damp-proof course at subfloor level ( a normal practice in 1982 and now) which can also serve as a type of expansion joint;

• No weep holes at the base of the wall;

• Detection of high rising damp levels in the brickwork near #1 (western end);

• Distorted eave gutter at the western end side wall discharging water on the wall;

• A rough ‘dish’ drain partly blocked with rubble between #1 and #3 discharging onto the respondents’ property at the base of the wall at its western end;

• Overland flow from elsewhere on #1 and other upslope properties discharging onto the north-western corner of the respondents’ property and the western end of the wall.

25. Based on his observations, Mr Barry lists the factors, in order of occurrence that he considers have caused the damage to the wall.

• 1982 - construction of a shallow footing partly on dissimilar foundation material; and absence of damp-proof course, vertical expansion joints and weep holes (primary reason);

• 1982 to date – long term effects of rising damp, overflowing gutters, and surface water discharge and the consequential softening of the founding soils; shallow footings in continual wet and dry environments are more vulnerable to damage caused by uneven foundation settlements;

• 1994 – [assumed] underpinning of eastern end of wall as part of the additions to #10. This has resulted in the eastern portion of the applicant’s rear wall being founded on stiffer material than the remained of the wall which is founded on softer material including some topsoil. The vertical crack component is at the boundary between the inadequately constructed footings and the underpinned section.

• Post 1982 to some time before 2001 [when the respondents purchased their property] – growth of trees; roots penetrated under the wall footing and into the subfloor of #3 predominantly within the topsoil layer; the proximity of the roots and planter would have added to the severity of the wall crack because of the inadequacy of the footing.

26. At [5.2.5.3] of his first report, Mr Barry states that The proximity of the tree roots and planter would have added to the severity of the wall crack only because of inadequately constructed shallow footing. Had the footing been constructed properly and in accordance with normal building practice circa 1982, such cracking would have been of much less significance. Further at [5.5.5.4]: We also consider that such a wall crack mechanism would have developed even if there were no tall trees or planter boxes in the vicinity.

27. Amongst other recommendations which deal with rectifying the drainage problem, Mr Barry recommends underpinning the wall with 4 x 600mm x 450mm mass concrete piers, repairing the wall and retrofitting a damp proof course.

OIKAS architectural drawings

28. In April 2016, the applicant engaged OIKOS Architects to prepare sketch plans for the reconstruction of the damaged rear wall in accordance with the suggestion made by Mr Rollo (see [18] above). This includes the retention of the existing footing and no apparent underpinning.

Barry report 16 May 2016

29. The respondents asked Mr Barry to review the report prepared by Mr Rollo. Mr Barry considers that his own report is based on more recent site visits and a more detailed investigation of three test holes. While he agrees there are some factors in common, such as the assumption that the end of the wall adjacent to #10 was probably underpinned, Mr Barry states that the key difference between his and Mr Rollo’s reports is that Mr Rollo attributes the sole cause of the crack to be uplift of the base of the footing from the roots of the China Doll tree.

30. In paragraph [2.0] Mr Barry states that while he is not an arborist, he considers the weight of the wall and footing to be in the order of 20Kn per lineal metre, with the assumed width of the footing at 500-600mm, the resulting pressure on the underlying soils would be between 33-40 KPa which would be the force required to be exceeded by a root. At [2.1.4] Mr Barry states: Based on our inspections, we are satisfied that whatever roots had penetrated under the footing and given the underlying soft moist soil conditions, they do not appear [to] have the capability of imposing such an upward force.

31. Mr Barry then goes on to summarise the issues he raised and which Mr Rollo did not, including: uneven settlement of shallow footings on soft soils; changes as a consequence of underpinning at #10; and absence of damp-proof course, ancillary flashing, or weepholes. At [6.0] Mr Barry disagrees with Mr Rollo’s statement that there was “no fundamental flaw in the original footing design or subsequent construction”; in Mr Barry’s opinion, “The damage that occurred was a classic uneven settlement type failure 30 years in the making. It was only the intrinsic strength of the face brickwork set in hard cementitious mortar that delayed the eventual failure. Had the mortar been “weaker” (1 part cement: 2parts lime: 9 parts sand), which is a common mix for residential construction, the failure could have occurred much earlier.”

Other

32. Exhibits 1 and C include correspondence between the parties, invoices from experts engaged by each party, and a number of quotes for the repair of the brick wall and or underpinning. In exhibit C there is an invoice for the replacement of a damaged toilet located in the rear bathroom. This was struck out as it was not part of the original claim. I note that in a letter dated 26 April 2016 from the respondents’ solicitors to the applicant, an offer of $4,770.00 was made to attempt to resolves the matter. The expenses incurred by the respondents are included in the letter. The offer was rejected by the applicant who presses her position that the respondents pay the full cost of the repairs to the wall. The respondents withdrew the offer and now press a cross-claim requiring the applicant to pay the costs associated with the removal of the trees, the reinstatement of their property and measures to remove damage to the respondents’ property caused by inadequate guttering and water run-off.

Jurisdiction

33. In applications made under s 7 Part 2 of the Trees Act, there are a number of jurisdictional tests that must be satisfied before the Court’s powers to make orders under s 9 of the Act are engaged.

34. I am satisfied that the trees were wholly located on the respondents’ property, being land adjoining the applicant’s property. Although the trees have been removed, they were present immediately before the damage occurred; therefore the trees are trees to which the Act applies (s 4(4)).

35. I am also satisfied on the evidence before me that the applicant has made a reasonable effort to reach agreement with the respondents; this satisfies the jurisdictional test in s 10(1). Although some dissatisfaction with the process was raised by the respondents’ solicitor, Mr Poulden, Preston CJ in Robson v Leischke [2008] NSWLEC 152; (2008) LGERA 280 at paragraphs [191] to [196] discusses the requirement of s 10(1). His Honour notes that such an attempt must have occurred prior to the making of an order. What one party considers ‘reasonable’ may not accord with another party’s interpretation.

36. In applications under Part 2, the key jurisdictional test is found in s 10(2). This states:

(2)   The Court must not make an order under this Part unless it is satisfied that the tree concerned:

(a)   has caused, is causing, or is likely in the near future to cause, damage to the applicant’s property, or

(b)   is likely to cause injury to any person.

37. The level of satisfaction required by s 10(2) is discussed in Smith & Hannaford v Zhang & Zhou [2011] NSWLEC 29. At [62] Craig J states in part “something more than a theoretical possibility is required in order to engage the power under [the Trees] Act…”.

38. The concept of causation is discussed in Robson v Leischke at [176] to [189]. At [179] Preston CJ observes that a tree which is the subject of an application need not be the sole cause of the damage in order to engage the Court’s jurisdiction. This is further considered in Smith & Hannaford at [30] where Craig J considered that an application can still be made under the Trees Act where there are multiple causes of damage and these include a tree about which an application can be made.

39. If any of the tests in s 10(2) are met, the Court’s jurisdiction is engaged. Section 9(1) enables the Court to make any orders it thinks fit in the circumstances. Without limiting the powers under s 9(1), s 9(2) indicates the range of orders which may be made. While s 9(2)(h) enables the Court to order the payment of costs associated with carrying out an order under this section, it does not include payment of costs for work to rectify a respondent’s property as a consequence of trees growing on a respondent’s land. Section 7 of the Trees Act enables an owner of land to apply to the Court to remedy, restrain, or prevent damage to property on the applicant’s land as a consequence of a tree that is on adjoining land. In respect of “costs” within the meaning of the Uniform Civil Procedure Act 2005, Rule 3.10(1)(a)(iv) of the Land and Environment Court Rules 2007 precludes Commissioners of the Court from awarding such costs. Should either party wish to do so, claims for costs must be made by a Notice of Motion, which is heard and determined by a Judge or the Registrar of the Court.

The hearing

40. During the on-site hearing I was assisted by Mr Barry, the respondents’ engineer.

41. At the time of the hearing, the trench along the wall had been backfilled. Excavation with a hand trowel revealed one remaining woody root, approximately 80mm in diameter, which had grown under the footing. Soft, organic topsoil was easily excavated from beneath the footing between the remaining section of root and the north-western corner of the respondent’s property where it adjoins #10.

42. Mr Barry reiterated his opinion that the primary cause of the crack in the wall is the uneven settlement of the footing as a consequence of the rigid support at the eastern end and the poor support provided at the western end by the soft, wet soil. He maintained his opinion as to the reactivity of clays. In Mr Barry’s opinion, the location of the root near the pivot point created by the rigidly supported end is effectively co-incidental and not the cause of the failure.

43. The applicant relies on Mr Rollo’s opinion and the findings in the MCS report. She asserts that the crack arises from upward pressure from the root causing the pivoting of the footing. The applicant maintains her position that the respondents should pay the full cost of replacing the wall.

44. Mr Poulden submits that the preponderance of probability is that the roots are not the cause of the crack. He cites Smith & Hannaford at [51], a similar matter involving roots and footings, where all the engineers who inspected the site acknowledged that even the largest roots observed (up to 100 x 120mm) could not provide the force required to create the uplift of the footings. The respondents rely on Mr Barry’s opinion that even in the absence of the tree roots, the wall would have eventually cracked.

Consideration

45. I disagree with Mr Barry’s and Mr Nicholas’ conclusions about there being reactive clay soils. With the expertise in soils I bring to the Court, I concur with Ms Hunt’s statement at [11] of this judgment. I also somewhat disagree with Mr Barry’s statement that the footing was set above natural ground level on the basis it was above the level of the respondents’ paving. It would be not unreasonable to assume that given the obvious and natural cross fall in the land that the respondents’ backyard has been levelled and paved since 1982. During the hearing the first respondent stated that the paving was installed when the house was purchased in 2001. While I understand the point he is trying to make, the site has also been disturbed through the processes of investigation.

46. With the benefit of the site inspection and on the basis of the engineers’ reports, in particular by Mr Barry’s explanation, I am persuaded that the principal cause of the crack is most probably the uneven settling of the footing. I also note the other possible causes identified by Ms Hunt (see [10] and [11] of this judgment) and Mr Barry including changes to the loading on the footing as a consequence of the 2001 renovation, the absence of weep holes and damp proof course, and the nature of the foundation material. However, that said, I am also satisfied that the possible influence of the tree roots cannot be disregarded and their possible influence needs more consideration.

47. There is no doubt that roots from the respondents’ China Doll tree have penetrated beneath the concrete footing on which the applicant’s rear wall is built. Image 12 in the MCS report shows the vertical portion of the crack opposite the western trunk of the China Doll tree. The crack extends down to at least the top of the soil in the planter box. Photographs included in Mr Rollo’s report show the trench after the removal of the trees and the planter box. The crack does not extend through 8 or 9 courses of bricks to the footing below. Neither Mr Rollo nor Mr Barry, who both had the opportunity to closely inspect the exposed footing, noted any cracking of the footing itself. However, Mr Rollo’s report does include a close up photograph of the remains of roots significantly larger than the one remaining root I observed during the hearing and which appear to be growing under the footing in the north-western corner of the respondents’ property. The soil around the roots appears similar to the topsoil observed during the hearing. My understanding is that further root grinding took place between Mr Rollo’s inspection and Mr Barry’s inspections. Photograph 17 in Mr Barry’s first report would appear to confirm this, as the roots have been removed and the space backfilled with topsoil.

48. Mr Barry’s report includes estimates of the likely load of the wall and footing on the underlying soils; in part, this is based on the assumptions he makes about the width of the footing which presumably come from the 1982 architect’s drawings. In his opinion the roots would not be able to counteract this force because the overlying pressure would be such that the growth of roots would deform the surrounding soil rather than lift the footing. Mr Barry maintains that the soft top soil he observed around the roots validates his assumption. In oral evidence, Mr Barry opined that even with a firmer base, there would be a degree of deformation of the root before a structure was lifted.

49. In Smith & Hannaford, a matter which considered whether roots of a Sydney Blue Gum had caused cracking of walls and footings of the applicants’ dwelling, one of the arboricultural experts was noted (at [43]), as citing research suggesting that the likely maximum pressure a tree root would impose upon rock in which it was growing would be about 860kPa.

50. Based on this citation and in accordance with s 38(2) of the Land and Environment Court Act 1979 I have taken advantage of research documented in Biddle P.G. (1998) Tree Root Damage to Buildings: Volume 1 Causes, Diagnosis and Remedy Willowmead Publishing Ltd, Wantage at pages 159-162. This confirms the figure of 860kPa suggested as the pressure generated by the secondary (woody) growth of roots. In that book there are several examples of calculations that could be applied in order to determine the likelihood of the lifting of walls, slabs and footings by roots. It is clear from the text that there are many variables to be factored in, including the actual dimensions of a footing, the weight of the structure, the diameter of the root or roots, the rigidity of the ends of a wall, and the nature of the surrounding soil. At page 161, the conclusion is made that it is usually impractical to make precise calculations on whether roots have caused damage, or might be capable of damage and that it may be preferable to rely on general conclusions including, relevantly point vi on p. 162, a more heavily loaded structure such as a house foundation is likely to withstand any lifting force exerted by roots.

51. Without wishing to adopt this conclusion uncritically and in contextualising this generality to the circumstances of this matter, I note that:

• the footing is not cracked nor are the eight or nine courses of bricks above it;

• the photographs in the Rollo report of the remaining roots appear to show them in topsoil;

• Mr Rollo describes the underlying soils as being a mixture of clay and silty, sandy soils with some signs of sandstone that he attributes to be possibly fill material due to the adjacent sewer;

• Mr Barry found the soil to be 50-100mm topsoil over soft sandy/clayey soil; at the time of the hearing the surrounding soil was soft however, there had been considerable disturbance since the trenching; and

• the roots were in close proximity to the section of wall assumed by both engineers to be underpinned and therefore rigid.

52. I also agree with Mr Barry that given the position of the western end of the wall in relation to overland flow and roof water from #1 and possibly #3, water is likely to accumulate and soften the soil at that end. The root I observed beneath the footing was not large nor was it deformed as it may have been if it had been growing between very compacted soil or rock and the footing. The photograph of the larger roots in Mr Rollo’s report shows no significant lateral deformation of them.

Conclusions and orders

53. Therefore, while it is clear that roots of the China Doll tree were found beneath the footing, having considered all of the evidence before me, I am not satisfied to the extent required by s 10(2), that a “preponderance of probability” of the causal nexus between the roots and the damage exists; specifically the applicant’s contention that upward pressure of the roots of the China Doll tree has caused the crack in the wall. Whether the mass of roots created a short extension of a static pivot point beyond the rigidly supported eastern end of the wall has not been suggested by any engineer and not something I am qualified to determine absent any expert evidence. In my view the “preponderance of probability” as to the cause of the damage lies with the construction of the footing and the difference in support at its eastern and western ends and possibly exacerbated by the other factors described by Ms Hunt and Mr Barry (and not addressed by the applicant or by the applicant's engineer). Although there still remains a very small possibility that the roots played some role, I am not satisfied that the role they might have played warrants any contribution by the respondents to the repair or reconstruction of the wall. The respondents took the initiative of notifying the applicant about the crack and were prompt in taking action to remove the trees and the planter box. The removal of these elements will facilitate the necessary works to rectify the wall.

54. As discussed during the hearing, the applicant will need to seek advice from the council as to whether or not a development application is required.

55. As a consequence, the Orders of the Court are:

1. The application is dismissed.

2. The exhibits except A are returned.

____________________

Judy Fakes

Commissioner of the Court

**********

Decision last updated: 28 June 2016