LI KUEN KWAI JAY AND ANOTHER v. LOK CHUN CHEONG AND ANOTHER

DCCJ 1922/2016

[2019] HKDC 677

IN THE DISTRICT COURT OF THE

HONG KONG SPECIAL ADMINISTRATIVE REGION

CIVIL ACTION NO 1922 OF 2016

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JUDGMENT

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A. BACKGROUND

1.  This case is about an unfortunate affliction not infrequently visited upon multistoried buildings in Hong Kong.  Our multistoried buildings are usually in multiple ownership and occupancy.  They share common walls, ceiling slabs and external walls.  Water and waste disposal piping from each unit is connected to common piping throughout the building. As each year of habitation takes its inevitable toll on the building, it is only natural that all kinds of structural problems would occur as the building ages.  One such problem is water seepage.  This is one such case.

2.  The building in question is one of the residential buildings in the South Horizon Development in Apleichau, Island South of Hong Kong.  This development was built in the early 1990s.  It is now close to 30 years old.  It is not surprising, therefore, that water leaking from ageing pipes and continued use would have eroded protective layers, leading to water seepages.  But because there is so much that is commonly shared and uses are so varied in multi-storied buildings, it is rare that there is a ready answer to the question as to where water seepages originate.

3.  Seepage in a multi-storied building is usually dealt with between the occupant/owner of the apartment suspected to be the source and the occupant/owner of the apartment suffering from the seepage, with the assistance of building management.  Most Deeds of Mutual Covenant in multistoried buildings, as in this case, would require individual owners to keep their units in good order so as not to cause loss, damage or nuisance to other owners.  If this co-operative effort fails to resolve the problem, the Joint Office (“the Joint Office”) set up by the Government comprising the Buildings Department (“BD”) and the Food and Environmental Hygiene Department (“FEHD”) is called in.  Section 127 of the Public Health and Municipal Services Ordinance, Cap 132, empowers the FEHD to issue a Nuisance Notice to the owner/occupier of a flat suspected of water leakage to take steps to stop the leakage (“Nuisance Notice”).  If the Nuisance Notice is not complied with, the FEHD may apply to court for a summary Nuisance Order, ordering compliance with the steps stipulated in the Nuisance Notice but this only occurs if the FEHD makes a positive finding of water leakage or seepage from the suspect premises.  If the previous steps fail to resolve the problem, a dis-satisfied occupant is often left with little option but to take a step of last resort – litigation in our courts.  The events in this case essentially followed this same trajectory.

4.  The plaintiffs in this Action are the joint owners and occupants of Flat 5E on the 5^th Floor of Tower 11, Yee Fung Court, in South Horizons (“5E”).  The 2^nd plaintiff Leung Wing Tung, Lilian (“Leung”), who gave evidence for the plaintiffs, said they purchased 5E on 5 November 2009 and then soon started renovation of these premises.  Leung testified that the plaintiffs moved into 5E around January 2010.  She said that sometime in 2010, she noticed water seepage^[1] coming from the flat above (6E), affecting 5E’s (i) ceiling of Guest Bathroom, (ii) ceiling of Master Bathroom, and (iii) ceiling of her corridor & the partition wall, but she did nothing about it until about February 2012, when she made a formal complaint to the Management Office.

5.  The 1^st defendant (“Lok”), in giving evidence for the defence, stated that the initial complaint related only to the Guest Bathroom and corridor outside the Guest Bathroom (which was described as “internal corridor” in defendant’s case or submissions) of 5E and the complaints in relation to the Master Bathroom of 5E did not emerge until 2017 when the plaintiffs’ solicitors wrote to him about concrete spalling falling from the roof of the Master Bathroom. 

6.  The Management Office issued a letter to the defendants dated 7 May 2012 (“Management Company’s 1^st Letter”) informing the defendants that a complaint of water seepage into Flat 5E had been received and requested inspection of 6E as well as remedial measures.  The Management Office then conducted inspections and tests of both premises in May 2012 in the presence of the owners of 6E and 5E (“Joint Inspection”)[2] and by letter dated 17 August 2012 (“Management Company’s 2^nd Letter”), which letter did not mention the results of the inspections and tests carried out by the Management Company, requested the owners of 6E (the defendants) to take remedial steps. 

7.  According to the defendants, the Management Company had carried out many inspections and tests including water ponding tests (with a dye) (technically known as the “Fluorescent Dye Test” or “FDT”)[3] which were conducted between May and October 2012, but they did not produce any evidence of seepage from 6E to 5E.  Lok under cross examination said the Management Office verbally told him that the Management Office observed no color patches (which would indicate a positive result of the ponding tests) on the ceilings of the Guest Bathroom and internal corridor of 5E.  Nevertheless, according to Lok, the plaintiffs kept lodging water seepage complaints.

8.  It is not in dispute between the parties that back in early 2012, the defendants, after receiving complaints from the plaintiffs, did at their own (defendants’) expense conduct the following initial repairs (“2012 Ps’ Premises Repair Works”) to the Guest Bathroom and the internal corridor in 5E:-

(i)   In relation to the walls of the internal corridor:-

(a) Removing the existing layer of plaster on the walls;

(b) Re-plastering and skim coating the walls; and

(c) Repainting the walls

(ii)   In relation to the walls of the ceiling of the Guest Bathroom:-

(a) Removing the existing layer of plaster on the ceiling;

(b) Carrying out chemical grout injection to the ceiling; and

(c) Re-plastering and skim coating the ceiling.

9.  The 2012 Ps’ Premises Repair Works did not, however, satisfy the plaintiffs, and so, the Joint Inspection was conducted in May 2012.  There were further complaints from the plaintiffs and the letter of 17 August 2012 from the Management Office (“Management Company’s 2^nd Letter”) was issued requesting remedial action.  This letter made, inter alia, the following statement:-

“於八月十三日，我們再次到訪五樓E座單位進行視察，發現走廊天花及牆身仍然出現滲漏情況，故懷疑 貴單位滲漏情況仍然持續.”

10.  By this time, the Joint Office had been called in.  On 5 July 2012, staff of the Joint Office visited 6E and 5E and carried out FDTs to the drainage inlets of the hand basins, toilets, floor drains and bath tubs of both bathrooms in 6E.  In a report dated the same day, one Chow Suk Yee of the Joint Office reported that no colour stain was observed in the “affected areas” of 5E.  On 2 August 2012, staff of the Joint Office visited 5E for a second time and reported that no colour stain was observed in the ceiling and walls of internal corridor and the ceiling of the Guest Bathroom[4].

11.  In December 2012, the defendants caused a second series of repairs (“2012 Ds’ Premises Repair Work”) to be undertaken on the Guest Bathroom in their own premises (6E) (which is directly above the Guest Bathroom of 5E).  These repair works appeared to be quite extensive and designed to prevent water leakage, and consisted of the following:-

(i)   Removing all the existing fixtures in the Guest Bathroom, including the hand basin, toilet and bath tub;

(ii)   Removing the original tiles and screeding on the floor and the walls;

(iii)   Replacing the original supply and drainage pipes, which were galvanised iron pipes, with copper pipes (which are more expensive, more durable and higher quality than galvanised iron pipes);

(iv)   Laying cementitious waterproofing coating on the floor and the walls up to the underside of the ceiling;

(v)   Laying E-mix waterproofing screed layer on the floor and the walls, on top of the cementitious waterproofing layer;

(vi)   Laying new tiles on the floor, on top of the E-mix waterproofing screed layer;

(vii)   Filling the gaps between the floor tiles with mastic grout;

(viii)   Applying Dip Etanche transparent waterproofing layer on top of the new floor tiles and on the walls; and

(ix)   Installing new fixtures, including a new hand basin, a toilet and a shower

12.  The 1^st defendant (Lok) asserted that he had ensured that the best materials and workmanship were deployed in such works.

13.  Despite the 2012 Ds’ Premises Repair Work, the plaintiffs remained dis-satisfied and continued to complain of water seepage.

14.  On 26 February 2013, the FEHD issued a Nuisance Notice to the defendants directing that the floor platform (地台) of the Guest Bathroom in 6E be repaired to prevent any leakage.  The FEHD was probably unaware at this time that the 2012 Ds’ Premises Repair Work had been completed.

15.  On 16 April 2013, the FEHD visited 6E and observed that the defendants had refurbished the floor platform of the Guest Bathroom of 6E.  On that same day, the FEHD staff also conducted an FDT at the Guest Bathroom of 6E and visited 5E the following day, observing no coloured dye.  A further visit on 23 August 2013 by the FEHD observed no coloured dye at 5E[5].

16.  The FEHD further together with its nominated consultant visited 6E on 29 August 2013 to conduct confirmatory FDT, reporting negative results.  The FEHD also thereafter on 19 September 2013 and 18 February 2014 conducted further FDT for potential seepage from 6E to 5E but did not by these tests find any evidence of seepage[6].

17.  In September 2013, a third round of repair works (“2013 Ps’ Premises Repair Works”)also at the defendants’ expense, was conducted in the Guest Bathroom and internal corridor of 5E, consisting of the following:-

(i)   In relation to the walls of internal corridor:-

(a) Removing the existing layer of plaster on the walls;

(b) Re-plastering and skim coating the walls; and

(c) Repainting the walls.

(ii)   In relation to the walls of the ceiling of the Guest Bathroom:-

(a) Removing the existing layer of plaster on the ceiling;

(b) Carrying out chemical grouting injection to the ceiling; and

(c) Re-plastering and skim coating the ceiling.

18.  This 3^rd round of repairs did not also satisfy the plaintiffs who kept on complaining about water leakage.

19.  Thus, in about April 2014, the defendants also refurbished the Master Bathroom in 6E (“2014 Ds’ Premises Repair Works”), to prevent water leakage to the flat below, although up to this point in time, according to Lok (the 1^st defendant), who gave evidence, that there had been no complaint about water leakage from the Master Bathroom of 6E.  The 2014 Ds’ Premises Repair Worksdone to the Master Bathroom in 5E, included the following:-

(i)   Removing the existing toilet and installing a new toilet which was designed in a way that any overflowing toilet water would flow back to the toilet bowl;

(ii)   Removing the existing hand basin, conducting drainage tests on the existing draining pipes of the hand basin, and installing a new hand basin together with a new floor cabinet;

(iii)   Conducting pressure tests on other existing pipes;

(iv)   Laying new cementitious waterproofing coating on the floor, on top of the existing floor tiles;

(v)   Laying new floor tiles, on top of new cementitious waterproofing coating;

(vi)   Filling the gaps between the new floor tiles with mastic grout; and

(vii)   Applying Dip Etanche transparent waterproofing to the new floor tiles, to the walls, to the junctions between the walls, and to the junctions between the walls and with the floor or the bathroom fixtures.

20.  The plaintiffs in their evidence dubbed the aforesaid four rounds of repair works undertaken respectively on 5E and 6E by the defendants at the latter’s expense, collectively as “the Four Works”.  While the plaintiffs did not dispute that the Four Works had been undertaken at the material times, they found the workmanship “ineffective” and the standard of workmanship “not good enough”.  No elaboration was provided by the plaintiffs save their allegation that these works failed to stop the seepage in the affected areas in 5E.

21.  Despite the Four Works undertaken at 5E and 6E at the expense of the defendants, complaints from the plaintiffs continued into 2015, and joint visits by the 1^st defendant with the Management of South Horizons and the plaintiffs took place in November 2015 (“Joint Inspection”).  The Joint Inspection also included the 1^st defendant’s colleague Mr Vincent Chan, who was a chartered surveyor and professional surveyor.  The Joint Inspection covered the Guest Bathroom, Master Bathroom and internal corridor of 5E.  The Joint Inspection “found that there were no water droplets and no damp patches on the ceilings”.  Photos were taken during the Joint Inspection and were exhibited with the witness statement of Lok[7].

22.  On 26 April 2016, this Action was commenced by writ taken out from the District Court seeking an order against the defendants requiring them to rectify the water seepage emanating from 6E and restraining them from causing or permitting such seepage, and damages.  By commencing this Action, it is probable that the plaintiffs had waited long enough for the Joint Office to take action.  This Action is based on the defendants’ contractual duty in the Deed of Mutual Covenant to keep their premises in good repair in order to avoid loss or damage to other unit owners and their common law duty of care to the plaintiffs.

23.  Then, the Joint Office sent a letter dated 3 May 2016 to the owners of 5E and 6E informing them that since the non-destructive tests conducted by Joint Office and its nominated consultant could not ascertain the source of the seepage, the Joint Office would take no further action. The letter was in the following terms:-

“業主 / 住戶：

有關香港南區海怡半島11座5樓E室天花滲水事宜

就上述滲水個案，本處曾於2013年2月26日根據《公眾衛生及市政條例》第127(1)條向閣下發出「妨擾事故通知」，規定在限期內完成所需的維修工程。

本處職員於2013年4月17日及2013年8月23日到下層單位跟進調查，發現受影響的天花仍有滲水情況。本處人員亦於2013年4月16日到貴單位跟進調查，確定閣下已妥善維修客人浴室的地台。因此，本處職員聯同本處委派的合約顧問公司職員其後於2013年8月29日在貴單位的客人浴室的地台進行覆核測試，並於2013年9月19日及2014年2月18日再到下層單位作跟進調查，惟並未發現覆核測試所使用的色水於下層單位滲水位置出現。

由於本處已進行既定的非破壞性測試仍無法確定滲水源頭，因此本處只好暫時停止跟進此個案。…”

24.  On 3 October 2017 and 17 October 2017, the defendants’ Solicitors received two letters from the plaintiffs’ Solicitors complaining of falling spalling from the ceiling of the Master Bedroom in 5E (“SHC Letters”).  This, according to the 1^st defendant (Lok), the SHC letters “were wrong to state that spalling occurred in the ‘master bedroom’.  Photos attached to the SHC Letters were clearly taken in the master bathroom and they showed spalled pieces of concrete lying in a bathtub, and concrete missing from an area of a ceiling where pipes were installed.”[8] Lok said this was the first time that a complaint of water leakage regarding the Master Bathroom and/or Master Bedroom in 5E was made.

B.   THE LEGAL PRINCIPLES

25.  There is very little in dispute as to the relevant legal principles.

26.  It is admitted that the defendants owe the plaintiffs a contractual duty of care under the Deed of Mutual Covenant in the following terms:-

“Each Owner shall maintain his own unit in good repair and condition to the satisfaction of the Manager of the Estate and in such manner so as to avoid any loss, damage or nuisance or annoyance to other owners.”

27.  Section 34H of the Building Management Ordinance, Cap 344, Laws of Hong Kong, also imposes a duty on the person having the right of exclusive possession in a multistoried building, to maintain the premises in his exclusive possession in good repair and condition.

28.  It is also admitted that the defendants owe the plaintiffs a common law duty of care to avoid negligently damaging the property of the plaintiffs.

29.  The question is whether there had been breach of either the contractual or the common law duty of care.  In this respect, in relation to water seepage, both parties agree that the following principles shall apply:-

(i)   The doctrine of res ipsa loquitur does not apply, and the burden is on the plaintiff to prove, on a balance of probabilities, that the seepage originated from the defendants’ premises (6E).

(ii)   The defendants have no duty to identify the source of the leakage[9].

(iii)   Where the water leakage remains a mystery at the end of the trial (ie where the plaintiffs fail to prove, on a balance of probabilities, that the source of the seepage originated from the defendant’s apartment), then the court should dismiss the action[10].

30.  Counsel for both sides cited a few more cases in support of their submissions.  I have considered all of these.  To the extent necessary, I will refer to these cases in the discussion below.

C.   THE EVIDENCE

31.  Madam Leung Wing Tung Lilian (“Leung”) the 2^nd plaintiff gave evidence at the trial, as did Mr Lok Chun Cheong (“Lok”), the 1^st defendant.  In addition, the plaintiffs’ expert, Ms Lau Shan La (“Lau”) and the defendants’ expert, Mr Tsang Chun Wang (“Tsang”) gave evidence.

32.  I have re-read and carefully considered the evidence presented.  As the evidence was presented over a period of 4 days, it would not be possible for me to enumerate all of this evidence. I hope the parties will understand that I could only expressly deal with such evidence as is crucial in helping me come to a decision.

The Expert Evidence

33.  The focus of the cross-examination at the trial was on the experts.  I will, therefore, first deal with the evidence of the Expert Witnesses.

34.  The Expert Witness for the plaintiffs was Ms Lau Shan La (“Lau”), BSc (Engineering), Hong Kong Polytechnic University, Chartered Engineer (CEng), Registered Professional Engineer (RPE), TCP-T5[11], AS(RGBC)[12], AS(RSC)[13], MHKIE[14], MICE[15], etc[16]. The plaintiffs Expert Report & Supplemental Expert Report made by Lau were all written in Chinese.

35.  The Expert Witness for the defendants was Mr Tsang Chun Wang (“Tsang”), BSc (Hons) (Surveying), Hong Kong Polytechnic University, Registered Professional Surveyor, Member of the Hong Kong Institute of Surveyors (HKIS).  The defendants’ Expert Report was done in English, but the Joint Survey Report by Lau and Tsang was written in Chinese.

36.  Lau by herself produced the following reports:-

(i)   The plaintiffs’ 1^st Survey Report dated 15 August 2015[17]; and

(ii)   The plaintiffs’ 2^nd Survey Report dated 14 November 2017[18].

37.  Tsang by himself produced the Water Seepage Investigation Report dated 25 April 2018 (“defendants’ Expert Report”)[19].

38.  The two experts following the conduct of tests at both 6E and 5E on 28 May and 28 June 2018, produced a Joint Survey Report dated 30 August 2018 (“Joint Expert Report”)[20]. For the Joint Expert Report, the two experts conducted the following six tests (the first 5 of which were common):-

(i)   Visual Inspection (目測法);

(ii)   High Resolution Thermal Scanning / Infrared Scan
(高清紅外線掃描法);

(iii)   Flow Meter Test (流量錶測試);

(iv)   Fluorescent Dye Test (“FDT”)
(螢光色水（蓄水）測試);

(v)   Electrical Moisture Meter (“EMM”)
(導電感應法); and

(vi)   Microwave Leakage Detection Test (“MLD”)
(微波濕度掃描法).

39.  The experts agreed on the suitability of the use of all the above tests, ie (i) Visual Inspection, (ii) High Resolution Thermal Scanning / Infrared Scan, (iii) Flow Meter Test, (iv) Fluorescent Dye Test and (v) Electrical Moisture Meter Test except the MLD. For reasons set out below in paragraphs 66-71, only the plaintiffs’ Expert, Lau, solely by herself, conducted the MLD, in addition to the 5 common tests.

40.  Both experts purported to conduct their tests in accordance with the “Professional Guide to Water Seepage investigation, Diagnosis, Testing & Reporting in Residential Buildings” First Edition 2014 (“Professional Guide”), issued by the Building Surveying Division of the Hong Kong Institute of Surveyors, and acknowledged the authority of the Professional Guide in defining the utility and limitations of the tests they conducted.

Negative results from Visual Inspection, Infrared Scan and Flow Meter Tests

41.  The first three tests by the experts, namely visual inspection, infrared scan and flow meter test, showed the common result that there was an accumulation of moisture present in the Guest Bathroom and Master Bathroom and the wall along the corridor in 5E.

42.  Visual inspection of 5E indicated indeed that there was an accumulation of moisture in the ceilings of the Guest Bathroom and the Master Bathroom as well as the walls of the corridor outside of the Guest Bathroom.  Infrared scans produced similar results.  However, both experts agreed that these tests could only show that there was an accumulation of moisture and possible seepage from outside of 5E, but they cannot determine the source of such seepage.

43.  The Flow Meter Tests were conducted to establish whether the fresh water supply pipes in 6E and 5E were leaking and therefore the potential source of leakage into 5E.  However, these tests established that there was no leakage in the fresh water pipes in either 5E or 6E.

44.  Thus, these tests cannot establish that the seepage came from 6E.  The two experts were, therefore, left with the results of the FDT and EMM tests conducted by them and the MLD Test conducted by Lau, the plaintiffs’ Expert.

Negative results from the FDT

45.  Paragraph 4.2.1 and Appendix 7.3 and 7.4 of the Professional Guide give a detailed guide as to how the Fluorescent Dye Test (FDT) should be conducted.  The relevant standard for such tests is stated to be ASTM D5957-98, 2005 – Standard Guide for Flood Testing Horizontal Waterproofing installations.  This test is also sometimes known as the “Ponding Test”, as referred to by the 1^st defendant in evidence.

46.  Dye mixed with water is placed in various places, bath tub, shower tray, water closet, floor drain and vertical grating in the suspected premises (6E Guest Bathroom and Master Bathroom) and a number of Check Points (“CPs”) in the seepage area (the Guest Bathroom Ceiling, and corridor walls outside Guest Bathroom and Master Bathroom in 5E).  In this case, a total of 8 CPs in the seepage areas in 5E were chosen.  The Professional Guide states that the appearance of colour dye in or around the seepage area should be a sign of seepage and allows one to trace its path from the test area.  If colour dye is not observed anywhere in or around the seepage area within three weeks of the flood test (FDT), the test should be negative.

47.  The FDT tests conducted by both experts during the two occasions of their joint visits to 5E and 6E on 8 checkpoints in 5E[21]. They all produced negative results.  In other words, there was no evidence of any colored water coming from 6E seen from these tests.

48.  I was reminded by counsel for the defendants during final submissions, that during cross-examination, Lau (the plaintiffs’ Expert), confirmed that she does not dispute the reliability of FDT in the present case and also, apart from the FDT jointly done by the two experts in 2018, the other FDTs conducted on the following occasions between 2012 and 2018, which also produced negative results:-

(i)   The FDT conducted by the Management Office on 6 October 2012[22];

(ii)   Tsang’s FDT reported in his 25 April 2018 Report[23]; and

(iii)   The Joint Office’s FDTs conducted on 5 July 2012 and 29 August 2013[24].

49.  Faced with these negative results, Lau (the plaintiffs’ Expert) pointed to the observation in p 23 of the Professional Guide to the effect that the dye test is not always successful and a failure to record its presence in the damp zone cannot be taken as conclusive evidence against the suspected source.  She suggests that the reason why there was no trace of dye on the checkpoints in 5E is as follows:-

“….由於物業上層（即6樓E室）住戶的用水習慣及混凝土有機會將色水過濾而導致色水無法滲透到物業（即5樓E室）天花或牆身表面”[25]。

50.  Tsang (the defendants’ Expert) in giving evidence, however, said that this was merely speculation because even if the dye is trapped between the concrete in the slabs between 6E and 5E, some dye could still be seen through the spalled concrete if there was seepage.  The absence of any evidence of coloured dye meant that there had been no seepage. Counsel for the defendants reminded the court in final submissions that Lau presented no evidence that habit of use of water by either of the parties could affect the negative FDT results.

51.  Lau also sought to counteract the negative FTD results by the results in two other tests, namely, EMM and MLD.

The EMM Test

52.  The EMM is an Electrical Moisture Meter designed to detect moisture through the measurement of electrical resistance.  The meter adopted by the Experts is a pin-type meter, which measures resistance and is referred to in the Professional Guide as an Electrical Resistance Meter.  The meter comes with two pins that puncture the surface to a depth of 3 mm, and the amount of moisture present in the concrete is measured by the amount of electrical resistance between the two pins.  The theory is that since electricity is better conducted by water, the more moisture there is in the area covered by the two pins, the less resistance there is to the passage of the electrical current.  The reading in the meter is in degrees of moisture.

53.  The EMM test is conducted in tandem with the FDT as shown in Appendix 7.4 of the Professional Guide.  It is the differences in readings before and after the FDT, which tends to show whether additional moisture had passed through the concrete slab and thus tend to show seepage from 6E to 5E.

54.  Appendix 7.4 of the Professional Guide suggests that Reference Points (“RPs”) should be set up around the CPs (Checkpoints in the seepage area) and EMM readings are made before the start of the FDT in the RPs as a baseline.  EMM readings are then made at end of the FDT, for comparison purposes.

55.  The Professional Guide points out that pin type EMMs were usually used for checking moisture content in wood and are usually calibrated for that purpose.  It cautions that corrections are necessary for different materials and ambient temperatures need to be recorded to make calibrations easier and temperature compensations and adjustments should be made with reference to the calibrated temperature and any moisture content obtained can reflect moisture gradient and contour changes between readings.

56.  The Professional Guide, while pointing to certain advantages, cautions against the pitfalls and limitations of the EMM:-

(i)   Potential Pitfalls during application

•   Some EMMs are calibrated for wood testing.  Selection of the correct test mode is required.

•   Tests that involve conductive materials will give invalid results.

•   Readings may be affected by the density of materials, aggregate size, smoothness of the measuring surface, surrounding temperatures, surface contaminants, hand pressure on electrodes, and contact area between the electrode and the testing material.

(ii)   Limitations of Method

•   Pinholes are left on the surface of the test object (electrical resistance meter)

•   For materials other than timber, scaling and calibration may be required

•   Not suitable for measuring hard surfaces such as marble or fair-faced concrete

•   Surface should be dry and free from contaminants and salts

•   Generally measures of dampness near the surface. Certain models may be able to measure dampness in concrete to a depth of 20 mm, hence eliminating the possible influence of surface condensation.

•   Usage prohibited in electrical conductive materials

57.  The 8 CPs chosen for the FTD were in the following seepage areas in 5E:-

(i)   Wall A (wall on the other side of the corridor to the Guest Bathroom);

(ii)   Wall B (wall on the side of the corridor of the Guest Bathroom);

(iii)   Ceiling of the Guest Bathroom;

(iv)   Ceiling of the Master Bathroom; and

(v)   Ceiling of the Corridor.

58.  The 86 RPs for the EMM Tests were distributed around each of the 8 CPs in the 5 seepage areas in 5E.

59.  Lau, the plaintiffs’ Expert, expressed her conclusions from this EMM test, as follows:-

“根據度電感應法（針入式）結果顯示，可見原告人物業單位（即5樓E室）走廊牆身B，客廁天花及主廁天花部分測試點的濕度度數於被告人物業單位（即6樓E座）進行螢光水測試後有明顯上升[26]”。

60.  From this conclusion, she extrapolates to the further conclusion that the seepage had come from 6E upon the hypothesis that although the FTD had failed to identify 6E as the source of the seepage, the increase of moisture in the ceiling of the Guest Bathroom and the Master Bathroom in 5E detected by the EMM after the FDTs would indicate seepage from above.

61.  Tsang, the defendants’ Expert, pointed out that the changes in readings observed by Lau in the RPs, recorded immediately before and after each FDT, were generally minor.  Tsang suggests thatincreases of over 20 degrees of moisture on before and after FDT EMM measurements could only be regarded as significant, based on industry practice and his professional experience[27]. Although Lau disagreed with this suggestion by Tsang, she did not provide contradictory evidence[28].

62.  Tsang’s analysis of the EMM results were as follows:-

(i)  Wall A (wall on the other side of the corridor to the Guest Bathroom):

Of the 18 RPs tested by EMM before and after FDT, none (emphasis added) showed any significant increase in moisture content of the concrete slab[29].

(ii)  Wall B (wall on the side of the corridor of the Guest Bathroom):

Of the 30 RPs tested by EMM before and after FDT, only 1 (emphasis added) showed any significant increase in moisture content in the concrete slab[30].

(iii)  Ceiling of the Guest Bathroom:

Of the 20 RPs tested by EMM before and after FDT, only 4 (emphasis added) showed any significant increase in moisture content in the concrete slab[31].

(iv)  Ceiling of the Master Bathroom:

Of the 14 RPs tested by EMM before and after FDT, none (emphasis added) showed any significant increase in moisture content in the concrete slab[32].

(v)  Ceiling of the Corridor:

Of the 4 RPs tested by EMM before and after FDT, none (emphasis added) showed any significant increase in moisture content in the concrete slab[33].

63.  In relation to the small number of instances where significant increases in moisture were noted in relation Wall B in the corridor and the ceiling of the Guest Bathroom in 5E, Tsang suggested that these are discrepancies caused by erroneous insertion of the pins in the EMM[34].

64.  Tsang also referred to the rainfall data of the Hong Kong observatory during the times the EMM tests were conducted.  During those times, there was little rainfall and yet the surface humidity in the corridor wall as well as the ceiling of the Guest Bathroom in 5E was high, with moisture readings exceeding 35 degrees in many cases and even to 99.9 degrees in some.  Thus, the EMM data showing small variations in moisture readings have little value in pointing to 6E as the source of the seepage and only significant changes in moisture readings before and after FDT could be trusted.  Accordingly, he does not think that the small number (6 out of 86) of increased moisture readings which could be regarded as significant, could be relied upon to show that there had been seepage from 6E[35].

65.  In cross examination, Lau accepted that discrepancies in EMM readings could be due to the following situations:-

(i)   Hand pressure differences in taking the readings at different times;

(ii)   Differences in ambient temperature at the different times when readings were taken;

(iii)   Differences in humidity at the different times readings were taken;

(iv)   Failure to take readings at the same point at different times when readings were taken.

The MLD Test

66.  MLD stands for Microwave Leakage Detection.  The meter is used to evaluate “free” moisture content by measuring the dielectric constant (electricity storing capacity) of the material being tested.

67.  Only Lau (the plaintiffs’ Expert) conducted this test.  Her conclusions arising from this test is as follows:-

“檢驗人員利用微波濕度掃瞄法，對物業（即5樓E室）客廁天花進行測試，檢驗人員利用三種不同深度的探頭，分別包括110 mm，70 mm及30 mm深度探頭進行測試。天花的測試的面積為1971mm x 1450mm，每個測試點距離約為493mm x 483 mm[36].”

“微波濕度掃瞄結果顯示，物業（及5樓E室）客廁天花的滲水水源頭位於天花上方（即6樓 E室）客廁抵台。水分由上滲入至物業（即5樓E室）客廁天花表面四周擴散[37]”

68.  Tsang (the defendants’ Expert) points out that the concrete slab between 5E and 6E would have metal reinforcement bars and because of this presence MLD conducted at the ceiling of the Guest Bathroom could produce false readings.  He refers to p 32 of the Professional Guide in the Joint Survey Report[38]. In addition, he had the following to say:-

“微波濕度掃描法結果並不能作滲水源頭的參考指標，根據香港測量師學會所撰寫的（Professional guide to water seepage）當中第32頁（見下圖B5）說明，[“The presence of metals in the tested material (e.g. concrete reinforcement) can give false reading”[E/1049]] 根據樓宇結構，5樓E室的天花內必定含有兩層鋼筋，因此微波掃描的數據並不能於此案中作參考”[39]

69.  The Professional Guide (p. 32) refers to the following pitfalls and limitations:-

Potential Pitfalls

•   Errors may occur with certain ceramics.

•   The presence of metals in the tested material (eg concrete reinforcement) can give false readings.

•   Water near the surface of the test object will heavily affect the readings.

•   Can only be used to measure damp areas along a wall or on a floor

Limitations of method

•   Attention should be paid to the interpretation of the readings when applied to elements that contain metal or ceramics.

•   Surface of the test object should be kept dry and flat.

•   Test surface must be open to the application of sensors.

70.  In cross-examination, Lau accepted the caveats in the Professional Guide relating to the MLD.  She also accepted that while the MLD readings showed different moisture content at various areas and different depths, they do not show the movement of the water, that is whether they come from above, horizontally or from below and therefore they cannot show that the source of the leakage comes from 6E.

71.  Tsang in re-examination pointed out that there is only one water path shown in the 110 mm map/diagram for Wall B (which did not have reinforced metal bars) and that path is from the floor.  As will be seen from the discussion on the factual evidence below, this observation is consistent with a layman’s test conducted by the 1^st defendant (Lok).

The factual evidence

72.  There was much factual evidence given by Leung and Lok.  Both factual witnesses were extensively cross-examined on matters which could not be said to be critical to the focal issue in this case, namely, whether the water seepage found in 5E originated from 6E. Therefore, I propose, in addition to the factual background narrative in paragraphs 1 to 23 above, only to give such treatment here to the factual evidence as might help to determine this focal issue.

73.  Lok pointed out that he refurbished his flat (6E) soon after the plaintiffs purchased 5E in about November 2009 but before they moved into the unit.  There were no complaints from the previous owners of 5E nor were there complaints before the plaintiffs moved into 5E but after they had bought the unit.  It was only after the plaintiffs moved in, sometime in 2010, that the complaints of seepage began.

74.  Lok said that the plaintiffs were persistent complainants and pointed out that in light of the frequent complaints by the plaintiffs, he had undertaken repairs at his own expense, despite there being no direct evidence that the seepage had come from 6E.  the plaintiffs, however, pointed out that the repair works undertaken by Lok were insufficient to stem the seepage from 6E, but Lok countered by pointing out that he, being a person experienced in the building industry, would be careful to ensure that all repair works were performed to high standards.

75.  Lok suggested that the seepage could have originated from the Guest Bathroom in 5E as he noticed that the shower in that bathroom was higher than the floor and it was possible that the seepage could have been the result of water flowing from this shower onto the floor and seeping into the floor slab of 5E.  Lok referred to an experiment he conducted by placing a dry piece of tissue paper on the corridor wall and finding it soaked the next day, suggesting that this soaking was the result of capillary action from the floor.

76.  Lok also referred to the false ceilings in the Guest Bathroom and the Master Bedroom Bathroom and that the accumulation of moisture on the ceiling inside these false ceilings could have been the result of showering with hot water in these bathrooms.  Both experts acknowledged the plausibility of these suggestions that do not consider these suggestions to be conclusive.

77.  There was some cross-examination of Lok as to the details for the monies he spent on the various repair works, presumably to establish some kind of baseline for the amount monies needed for repair works in the event the court finds that the seepage did come from 6E or to demonstrate the alleged parsimony of Lok by his scrimping on the Four Works.

D.   DETERMINATION

78.  I remind myself of the observations of Lam, J (as he then was) when a court has to choose between the versions of expert witnesses expressing different views to the court[40]. I also remind myself that expert witnesses could only help the court with their expert knowledge as would enable the court to make findings of fact.  It is for the court, and the court alone, to make the findings of fact.

79.  I also remind myself that the burden of proof lies squarely on the shoulders of the plaintiffs to demonstrate, on a balance of probabilities, that the seepage found in 5E did originate from 6E.

80.  Of all the tests conducted by the experts, the one test, which consistently showed a negative result, stands out as the most convincing.  This was the FDT conducted on two joint visits by the experts with 8 CPs with reference to the seepage areas set out in paragraph 56 above.  There is also neither suggestion nor evidence that the proper protocols were not followed in these tests.

81.  The FDT is a simple test.  It is simply the placing of water mixed with coloured dye in places in the suspect premises (6E in our case) and observation of any trace of the same dye in the putative affected premises (5E) sometime afterwards, to allow the coloured water to seep through if indeed there was a path in the concrete slab between 6E and 5E allowing seepage.  This test does not require other variables to be kept constant, and therefore is likely to produce fewer false positives.  I note that no coloured dye was observed in 5E long after each of the tests conducted.  Appendix 7.4 of the Professional 7.4.7 h states:-

“h. If colour dye is not observed anywhere in or around the seepage area within three weeks of the flood test, the test should be negative”. (emphasis added)

82.  FDTs were also independently conducted by the Management Office and by the FEHD on at least three occasions.  They all produced negative results.  There is neither suggestion nor evidence that proper test protocols were not followed.  These are parties with no interest in the affairs of the plaintiffs and the defendants.  I note that such independent tests have been viewed by the High Court as good and weighty evidence[41]. I take the same view.

83.  In addition, visual inspections and tests using infrared scans and flow meters undertaken by both experts also showed negative results.  The flow meter tests showed no leakage to the fresh water pipes in 6E and 5E.  Thus, seepage could not have come from leaking pipes.  The experts differ as to whether the waste water pipes in the external walls of the Building could have been a contributory cause of the seepage.  Lau said no but Tsang said he could not tell.  Lau was obviously trying to eliminate a source of seepage, but this was not agreed to by Tsang.  I cannot place any reliance on this and in any event, the burden still rests on the plaintiffs to prove that the seepage originated from the defendants’ premises.

84.  I take note of the fact that the defendants had made repairs on four occasions.  Although the plaintiffs assert that these repairs did not stem the seepage, I must take note of the fact that the 1^st defendant is in the building industry and in face of a persistent complainant such as the 1^st plaintiff, he would, more likely than not, ensure that the best materials and workmanship were deployed to avoid more complaints.  In fact, the 1^st defendant said that he had embarked on those repairs despite there being no direct evidence of seepage from his apartment (6E).  I have no hesitation in accepting the 1^st defendant’s evidence in this respect, as his reaction would have been the most rational in the circumstances.  The repairs and refurbishments made by the defendants, dubbed the Four Works by the plaintiffs, given their quality and extent, appear to me to be consistent with and tend to explain why the many FDTs resulted in negative findings.

85.  There is however a suggestion by Lau, the plaintiffs’ expert, that the negative results in the FDTs could not be relied on the basis that the Professional Guide suggested that negative FDT results cannot be taken as definite evidence against the suspected source[42]. But she did not refer the court to Appendix 7.4 h of the Professional Guide, which states that if there is no trace of coloured dye three weeks after the FDT, then the test should be negative.

86.  She also suggested[43] that habits in the use of water and the nature of the concrete slab could render it impossible for the dye to penetrate to the face of the ceiling wall in 5E.  Tsang disagrees with this, as he stated that the dye may still find it possible to penetrate through concrete spallings.  If indeed there was seepage from above and the water was trapped inside the concrete and then slowly seeps into 5E, one should see coloured dye traces sometime after the test, but none could be seen by either of the Experts, the FEHD or the Management Office, weeks after the FDT. 

87.  Lau also did not provide any evidence of water usage habits and did not demonstrate how such habits may produce negative results in FDTs.  Lau under cross-examination agreed that she could offer no evidence as to water usage habits in 6E.  Also, during cross-examination of Lau, it was put to her that “negative result of FDT could be evidence that water seepage may not be related to D’s unit in other words, if D’s unit was not the source of water seepage, there would not have color appeared?”  Lau agreed but followed up with the phrase “可能唔係”.  Lau further said that if there was a negative result from FDT, FEHD would say 未能確定源頭。

88.  Lau also suggested that as her EMM readings showed that as the RPs in 5E after the FDTs showed a pattern of high moisture, that indicated seepage from 6E.  She did not however dispute that the seepage areas in 5E were humid to start with, before the FDT and remained wet at the end of the FTD.  Lau’s premise was that there was a pattern of high moisture in the seepage area in 5E, but that does not necessarily indicate whether the coloured dye in the FDT did seep from 6E to 5E.

89.  During cross-examination of Lau by D’s Counsel, Lau agreed that there was less than one hour difference before the FDT (which the Defence described it in cross examination as ponding test (蓄水測試)) and the EMM reading.  Lau was asked whether the rise or fall in the reading is in fact unrelated to the ponding test, she disagreed.  It was further put to Lau that Tsang was correct in his assertion that “業界提「明顯上升」，是指超過20度變化?”  Lau disagreed and said “看有無一個pattern是明顯上升” (it depends whether there is a pattern for significant increase). 

90.  Tsang (the defendants’ Expert) pointed out that only significant differences of 20 degrees in moisture before and after an FDT are relevant to show seepage.  Although Lau disagreed with Tsang that a distinct difference must be in the region of 20 degrees of difference in moisture, she could not point to any professional literature or other evidence, which counters that opinion.  In the circumstances, I must accept Tsang’s evidence that only such significant increases of moisture before and after an FDT could indicate seepage from 6E to 5E.

91.  Tsang pointed out only a few readings in the 86 RPs showed a rise in moisture which may be recognized as significant[44].

92.  Tsang attributes these readings to have been the possible result of erroneous insertions of the pins in the EMM. According to Tsang, the rise in moisture implied in Lau’s small number of EMM readings cannot be taken to be a reliable indication of seepage from 6E. 

93.  I note that the preponderance of EMM readings showed only small changes in humidity readings in the 86 RPs in the seepage area in 5E, before and after the FDTs.  The exception was in the 6 cases of changes of over 20 degrees of moisture shown in the before and after readings.  6 out of 86 cannot on any view be statistically significant.  Such a small number would indicate that the readings were aberrant and could have been the result of errors in the usage of the EMM, as Tsang suggests and as shown in the Professional Guide. 

94.  I also note that all of the 86 RPs were all humid to start with (ranging from 35 degrees in many cases and 99.9 degrees of moisture in some cases), and the only 6 readings with comparative values of over 20 degrees of moisture were in close proximity to RPs, which did not exhibit significant moisture differences.  RP 3 and 23 in Wall B in 5E (with readings of over 20 degrees of difference in moisture) were in close proximity to RP 1 and 2, both of which showed very little change in moisture before and after the FDT.  RP 10 and 11, 13, 17 in the ceiling of the Guest Bathroom in 5E (with readings of over 20 degrees of difference in moisture) were in close proximity respectively to RP 9 and 12 and RP 14 and 18, all of which showed very little change in moisture before and after the FDT. This evidence suggests that these 6 significant rises observed in the EMM readings would more likely than not be false positives. 

95.  In light of the foregoing analysis of the evidence, I have no hesitation in accepting Tsang’s analysis of Lau’s EMM results and find that they cannot be relied upon to overturn the multiple and clear negative FDT results obtained both by the Experts, the Management Office and FEHD in this case. 

96.  Lau, the plaintiffs’ Expert, further relies on her MLD tests but here again, the validity of the test is tainted by the presence of metal reinforcements in the concrete slab between 5E and 6E. More importantly, Tsang points out, and Lau agreed, that the tests merely showed the presence of water but not the direction of flow and therefore, they do not show that the water came from 6E.

97.  In light of the foregoing analysis of the evidence, I have no hesitation in accepting Tsang’s evidence in preference to Lau’s.  Lau’s refutation of the negative results in the many FDTs by her reference to water usage habits and the nature of the concrete and the results of her EMM and MLD tests remain unconvincing and cannot stand up to the negative results of many FDTs conducted by the two Experts and independent parties over the 6 years between 2012 and 2018.  In coming to this conclusion, I also take note of the limitations of the EMM and MLD tests as set out in the Professional Guide.

98.  Therefore, I have no hesitation in finding that the plaintiffs have failed to demonstrate, on a balance of probabilities, that the seepage had come from 6E and therefore the case encapsulated in this Action cannot succeed.

99.  The defendants’ suggestion that the seepage had originated from 5E itself must remain a matter for speculation. It is not the function of this court to find the source of the seepage.  I will therefore make no finding on the defendants’ suggestion.

100.  The only outcome from the foregoing is that the Action must be dismissed.  The assessment of loss is therefore otiose in light of this outcome.

101.  I realize that this outcome must come as a disappointment to the plaintiffs.  But it is trite law that the owner of the above unit has no duty to identify the source of the leakage.  Thus, there is no obligation for the owner of a unit above to do any renovation work or repair work unless his unit was confirmed as the source of seepage, since repair / renovation work can only be effectively done when the source of seepage should be ascertained.

102.  I hope that the plaintiffs would take solace from the fact that in the present case, the defendants, owner of 6E above 5E, despite no source of seepage could be found by the independent parties, such as the Joint Office and the Management Office, did nevertheless undertake renovation works, 4 times at their own expense, trying obviously to solve the water seepage complaints raised by the plaintiffs over the years. The court realizes that the plaintiffs did not feel that the Four Works had the requisite quality but the court could only say that it was only logical and reasonable for the defendants to try to ensure the Four Works were duly carried out with good materials and a standard of workmanship designed to prevent annoyance to the plaintiffs in the face of persistent complaints from them.

E.   DISPOSITION

103.  It is hereby ORDERED THAT THIS ACTION BE DISMISSED.

104.  As I have not heard from the parties on costs, I make an Order Nisi that the plaintiffs shall pay the costs of this Action to the defendants, with Certificate for Counsel, to be taxed if not agreed at the District Court Scale.  The plaintiffs may, if they wish, make any submissions that there should be some other order as to costs, and if that is their wish, they may do so in writing within 14 days hereof.  If that were to take place, the defendants shall have 7 days thereafter to respond in writing, and the plaintiffs shall have another 7 days thereafter to make a final submission in writing.  If no written submission is received within 14 days of this Order Nisi, the Order shall become absolute.

105.  The parties are requested to submit for approval by this court, an agreed Draft Order within 14 days hereof.  If no agreement can be reached, the parties may present their own version.

F.   NOTE OF THANKS TO COUNSEL

106.  Last but not least, it remains for me to thank counsel for both sides for their extensive submissions and their detailed exploration of the evidence in examination of the witnesses.  The industry of counsel over a hearing lasting 5 days has lightened my burden considerably, and I am grateful to them.