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Survey of Flood Damage to Buildings Uncertainties and

VIEWS: 16 PAGES: 25

									Survey of Flood Damage
     to Buildings –
   Uncertainties and
   Standardisations
                         by


     Professor David Proverbs
            Flood Research Group
   School of Engineering and the Built Environment
             University of Wolverhampton
Climate Change: UK Implications
        Change:
 Experts predict that:
                 that:
   Temperature will rise by 3oC by 2100
                             o

   (unprecedented warming rate)
   (unprecedented warming rate)
   Mean sea levels will rise by around 25 cm by 2100
              levels
   Heavy rain will be 4-5 times more common in 2050
                       4-5
   than at present
   than
   1 in 100 year flooding event today will become 1 in 20
   year event by 2050
  “Regular and serious flooding will become a fact of life
       for many parts of the UK in years to come”
          UK Flooding Facts
          UK Flooding Facts
2 million homes and 185,000 commercial properties worth
over £215 billion
1.3 million hectares of agricultural land worth £7 billion
5 million people in England and Wales are at risk from
flooding
Autumn 2000 floods affected an estimated 10,000 homes
across the country with the estimated cost of £800 - 900
million
The worst flooding in 1953 claimed 480 lives and caused
damage valued at £5 billion
Today, a similar flood could cause more deaths and over £20
billion insured losses
         Assessment of
         Assessment of
    Flood-Damaged Property
    Flood-Damaged Property
      A Literature Review
       A Literature Review
Little consensus of opinion and ignorance of many factors
regarding damage assessment procedures or ‘optimal’
repair methods
Prone to subjectivity and significant variance
Existing guidance is mostly based on generalisation, ad-hoc
and simplistic
Lack of knowledge regarding appropriate drying methods
and their effectiveness
Highlighted the need of definitive guidance on flood-
damaged assessment and subsequent reinstatement works
      Flood Damage Research
      Flood Damage Research
Principle Aim:


    “To generate benchmarks in respect of flood
    “To
    damage remedial works for typical domestic
    properties based on the opinions of experts”
                                        experts”
      Flood Damage Research
      Flood Damage Research
The following aspects were also investigated:
  The importance of flood characteristics when undertaking
  an assessment of flood damage, and sources of information
  or methods to determine each characteristic
  Methods and/or equipment employed to dry flood-
  damaged buildings
  Methods used to determine if a building is sufficiently dry
  for repair works to commence
        Project Methodology
        Project Methodology
Questionnaire survey designed to collect data
regarding:
 Background information (details of employer, working area, job
 title and experience in assessing flood-damaged properties)
 Perceived importance of flood characteristics and methods used in
 practice to determine the characteristics
 Drying methods and their effectiveness (present and ideal)
 Methods used in practice to determine if a building is sufficiently
 dry (present and ideal)
 Repair strategies (present and ideal) and their performance (cost,
 time, quality and client satisfaction), based on common flood
 damage scenarios (floors, walls, doors and windows, utilities)
 presented in the form of digital photos taken from real footage of
 flood-damages properties
      Project Methodology
      Project Methodology
Example of flood damage scenario:
  “An external wall of a flood-damaged property has
         evidence of rising damp problem ”

                        Respondents were asked to
                        choose one from several
                        repair strategy options
                        provided
                        Additionally, they were
                        invited to add their own
                        strategy if this was not
                        listed
       Project Methodology
       Project Methodology
Questionnaire was distributed to:
  1800 members of the RICS’ Residential
  Faculty
  Members of the Chartered Institute of
  Loss Adjusters via an invitation (in the
  form of leaflet) to participate in the
  survey
  Additionally, data were collected
  through online questionnaire in the
  project website.
Overall, 289 completed questionnaires
were received
Characteristics of the respondents
Characteristics of the respondents
  Respondent organisations
   Estate agent/Housing Association         3.1
               Consulting engineers              7.6

                      Loss adjuster                                                 59.7
            Environmental Services         1.7
           Damage repair specialist              6.3

    Surveying consultancy practice                             23.3
              Architectural practice       0.7
                    Local authority        1.7

                Insurance company          1.4

                                       0         10       20     30   40   50      60      70

                                                       Percentage of respondents
Characteristics of the respondents
Characteristics of the respondents
  Operating regions of the respondents’ organisations
                 North-West                9.5
               East Midlands               9.9
                  South-East                                                48.9
    Yorkshire and Humberside                     12.7
                    Scotland       3.9
                 East Anglia               9.9
              West Midlands                     12.0
                 South-West                             18.0
                      Wales               8.8
                   The North             7.4

                               0         10             20     30   40      50     60
                                                Percentage of respondents
Characteristics of the respondents
Characteristics of the respondents
  Respondents’ levels of experience in terms of number of
  years in assessing flood-damaged properties
                                30
    Percentage of respondents




                                20




                                10




                                0
                                                   10-15


                                                           15-20


                                                                   20-25


                                                                           25-30


                                                                                   30-35


                                                                                           35-40


                                                                                                   40-45
                                            5-10
                                      0-5




                                     Number of years in assessing flood-damaged properties
          Perceptions of Flood
          Perceptions of Flood
            Characteristics
            Characteristics
Perceived importance of flood characteristics
 Flood characteristics   Mean Median   Mode   Rank
 Sewage and fasciae      3.67   4.00    4      1
 content
 Contaminant content     3.52   4.00    4      2
 Depth                   3.52   4.00    4      2
 Duration                3.33   3.00    3      4
 Source                  3.26   3.00    3      5
 Velocity                2.59   3.00    3      6
 Experts Perceptions of Flood
 Experts Perceptions of Flood
       Characteristics
       Characteristics
Strong evidence of positive relationships between the
importance of contaminant content, duration, source and
depth of the floodwater, and the number of properties
surveyed over the last 2, 5 and 10 years
   Experts with more experience consider these
   characteristics to be more important
 Experts Perceptions of Flood
 Experts Perceptions of Flood
       Characteristics
       Characteristics
Findings of methods to determine flood characteristics:
   Flood damage assessors relied heavily on visual
   inspections and independent judgments
   Local information and/or witnesses were also important
   sources of information, particularly for determining the
   depth and duration of the flood
   Suggests that current assessment of flood-damaged
   properties contains subjectivity and may therefore be
   prone to variation
Drying Methods Used in Practice
Drying Methods Used in Practice
 Surveyors consider various methods to assist drying
 rather than focusing on a single dominant method.
 The most popular method involved making use of any
 existing heating systems (practical and timely).
 The most popular ‘ideal’ drying method was to install
 temporary heating.
Drying Methods Used in Practice
Drying Methods Used in Practice
 Property size (in terms of volume, area, number
 of rooms) was the most important factor to
 determine the number of dehumidifiers to be
 installed in a flood-damaged property
    Some damage assessors would rely on
    experienced-based trial and error and
    generalisation of one dehumidifier per room
    or two per standard semidetached house
 Two-thirds of the respondents sealed off sections
 of the property to assist the drying procedure
Drying Methods Used in Practice
Drying Methods Used in Practice
 A high degree of subjectivity was again found in
 determining the number of sections to be sealed off
 Lack of knowledge in regard to appropriate
 methods to determine dampness levels, and hence
 reliance on subjective methods (i.e. based on visual
 observation and allowing a number of days after the
 flood)
 These methods were perceived to be the least
 effective but ironically used quite extensively
 The most effective method perceived was calcium
 carbide moisture metres
Repair Strategies Used in Practice
Repair Strategies Used in Practice
  Most popular strategy is not necessarily the best
  solution in terms of cost, quality, time and
  satisfaction nor the ‘benchmark’ for a particular
  scenario. However, most surveyors are satisfied that
  their current practice is the most appropriate
  solution
  The tendency is that any strategy which derives
  higher quality and/or satisfaction demands higher
  cost and vice versa
      There are few strategies which perform better
      in all aspects
Repair Strategies Used in Practice
Repair Strategies Used in Practice
In some scenarios, cost is not the most
important consideration
Some respondents would recommend an
alternative strategy than their present one
    The increased cost involved is the main
    reason for not employing strategies
    which delivered higher quality and
    satisfaction
         On-going Research at the
         On-going Research at the
          Flood Research Group
           Flood Research Group
  EPSRC International Network of Experts on Flood
  Damage and Repair (refer to flyer)


  Impact of flooding / risk of flooding on residential
property values and costs of insurance


  An investigation into the satisfaction levels of UK
domestic property occupiers’ with respect to flood
damage repair works
Acknowledgements
Acknowledgements

We gratefully acknowledge the financial support
provided by the sponsor of this research, Lloyds TSB
Insurance; and also the support in kind provided by
Rameses Associates and the RICS Foundation. We
also wish to thank building surveyors and loss
adjusters who participated in the questionnaire
survey.
              Selected list of relevant
               Selected list of relevant
              publications of the Flood
              publications of the Flood
                  Research Group
                   Research Group
Proverbs, D, Nicholas, J. and Holt, G.D. (2000) 'Surveying flood damage to domestic dwellings: The
present state of knowledge', RICS Research Foundation Paper Series, Volume 3, Number 8. ISBN 0-
84219-033-4

Nicholas, J., Holt, G. D., and Proverbs, D. (2001) Towards standardizing the assessment of flood
damaged properties in the UK. Structural Survey, Volume 19, Number 4, pp 163-172. ISSN 0263-080X.
Awards for Excellence 2002 most ‘Outstanding Paper’ in the 2001 volume.

Soetanto, R. and Proverbs, D.G. (2004) Impact of flood characteristics on damage caused to UK
domestic properties: the perceptions of building surveyors. Structural Survey Special Issue: Flooding:
Implications for the Construction Industry. Guest Editor: D.Proverbs, Volume 22, No 2, 95-104. ISBN 0-
86176-977-5

Nicholas, Proverbs and Holt (2001) An Investigation Into Factors Influencing The Assessment Of UK
Flood Damaged Domestic Properties, in Proceedings of RICS COBRA 2001 Conference, Glasgow
Caledonian University, 3rd –5th September, pp. 660-669. ISBN 1-84219-066-0 (2 vols.)

Soetanto, R., Proverbs, D.G. and Nicholas, J. (2002) Assessment of flood damage to domestic properties:
surveyors’ perceptions of flood characteristics. RICS COBRA Conference, Nottingham Trent University,
5-6 September 2002, pp 154-169. ISBN COBRA 2002: 1-84233-074-8. Awarded the RICS Building
Surveying Faculty Postgraduate Prize for 2002.

Samwinga, V. and Proverbs, D. (2003) Satisfaction Of Domestic Property Occupiers With Respect To
Flood Damage Repair Works. ARCOM Nineteenth Annual Conference, September 3-5, University of
Brighton, pp 869-878 ISBN 0 9534161 8 6
              Selected list of relevant
               Selected list of relevant
              publications of the Flood
              publications of the Flood
                  Research Group
                   Research Group
Soetanto, R. and Proverbs, D.G. (2003) Benchmarks for the repair of Flood Damaged External Walls.
Proceedings of the Royal Institution of Chartered Surveyors (RICS) COBRA Conference, University of
Wolverhampton, 1st to 2nd September, pp 149-162. ISBN 1-84219-148-9.

Samwinga, V., Homan, J. and Proverbs, D. (2004) Satisfaction issues in the reinstatement of flood
damaged domestic property. 4th International Postgraduate Research Conference, Salford University,
March 29th-April 4th, pp 184-195. ISBN 0 902896 63 6

Samwinga, V., Proverbs, D. and Homan, J. (2004) Exploring the experience of insured UK homeowners
in flood disasters. International RICS Construction and Building Research Conference (COBRA) 2004,
Leeds Metropolitan University, 7-8 September ISBN 1842191993

Lamond, J., Proverbs, D. and Antwi, A. (2005) The effects of floods and floodplain designation on
value of property: An analysis of past studies. The Second Scottish Conference for Postgraduate
Researchers of the Built and Natural Environment (ProBE), 16-17th November 2005, Glasgow
Caledonian University, Glasgow, pp. 633-642. Edited by Charles Egbu and Michael Tong. ISBN 1-
903661-83-X

Proverbs, D.G. and Soetanto, R. (2004) Flood Damaged Property: A Guide to Repair. Blackwell
Publishing. ISBN 1-4051-1616-1
D.Proverbs@wlv.ac.uk

								
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