Guide to loss prevention
© Getty Images/Warut Sintapanon

Water damage on construction sites

A guide to loss prevention

    alt txt



    Water damage is the second most frequent cause of loss during building projects, representing a large percentage of Construction All Risk (CAR) claims.

    Water damage occurs in large and small projects alike and it can bring an entire construction project to a halt. From rain entering a structure through openings in the roof and unfinished windows, to plumbing systems that leak when tested, to flood waters that appear when snow melts, water damage is a significant cause of loss to buildings under construction

    It can ruin  interiors, spur the growth of mould and damage electrical  equipment. It can result in construction delays as affected  areas dry out and damaged materials are discarded and  replaced. It can reduce profit and add significant delays  to completion schedules through clean up and replacement  times. The contractor will pay at least some of the costs  out of their own pocket in the form of deductibles, debris  removal costs that exceed the insurance coverage, and  income lost due to delays even when insurance applies  to the loss.

    Preventing water damage claims adds to a contractor‘s  bottom line. With a focus on reducing construction defects,  most water losses are preventable. Preventing water  damage is critical to a construction business owner, even if  insurance is in place. Losses can include property damage,  debris removal, re-work and delay costs, not to mention the  damage to reputation. It generally costs very little to prevent  water damage and primarily requires a focus on quality,  planning and testing throughout the construction process.

    Water damage occurs from water  entering the building envelope or from  internal building releases.

    These releases are most costly when  water sensitive equipment has been  installed prior to the water release or  intrusion, or after interior fit-out has  been completed.

    As well as direct costs of clean up, repair,  replacement and dealing with items  such as mould, there can be long delays  in restarting construction.


    Project Management and the Water Damage Prevention Plan

    Using good risk management practices that can be  implemented as part of the construction plan, most water  damage losses can be prevented with very little impact on  the budget. Prevention should be considered at all phases  of construction:

    • Pre-construction
    • During active construction
    • Project close out

    Usually there are items that are addressed at high level  as well as measures that are addressed best at site level.  Good project management to design out potential  sources of water damage coupled with a job-specific  water damage prevention plan should both be part of  any project.

    Water damage sources

    Internal building sources

    • Plumbing system
    • Mechanical system
    • Drainage system
    • Fire Protection system

    External water sources

    • Rain
    • Roofs and roof drains
    • Door & window openings/roof openings
    • Groundwater

    Construction defects

    • Door, window and wall deficiencies
    • Roof, gutter and window flashings
    • Waterproofing and damp proofing
    • Cracks and separations in waterproofing structures
    • Flooded excavations


    During the first phase, pre-construction, it is necessary  to design a formal Quality Assurance/Quality Control  (QA/QC) plan. Following this plan, additional peer review  of the construction drawings and specifications should be  performed before executing a project. Evaluate the contract  documents for areas of water infiltration susceptibility, and  consider the drainage of water away from the structure  and planned excavations.

    Design team should engineer out sources of water  damage. For example:

    • Combined service risers
    • Concealed pipework routes
    • Positioning of water tanks
    • Porous risers
    • Plumbing systems with a high vulnerability to failure (eg plastic push-fit and glue systems)

    The design should allow for:

    • Additional isolation valves
    • Riser upstands
    • Full and easy access to pipes
    • Temporary drainage points

    A comprehensive risk assessment should be  undertaken that considers, amongst other items:

    • Loss history
    • Occupancy
    • Susceptibility to water damage
    • Mitigation features
    • Safeguards

    A peer review of all construction drawings should be completed before construction work commences.  This should include a review of:

    • Methods
    • Materials
    • Code compliance
    • Compatibility with local conditions
    • Subcontractor standards
    • Quality control
    • Water drainage and site conditions

    Before starting construction, it is also important that the  contractor evaluate the inter-relationship of specified  materials and building systems.

    If an area of weakness is identified, clarification should be  sought from the engineer in the form of a Request for  Information (RFI). Schedule the installation and testing of  piping systems, such as hydronic systems, as early as  possible in the project. This will minimise damage, as the  majority of finished work will not have been started. Backup  power and pumping systems must also be considered to  prevent dewatering issues during construction.

    Water leak detection units

    © Getty Images/Jose A. Bernat

    One of the most effective ways of reducing damage from  water leaks in projects is to use a water leak detection unit.  These are installed into the water mains supply and can  be installed for the building or on a floor by floor or even  room by room basis.

    The unit works by monitoring the volume of water in litres  used in any selected time periods, for example per half hour  or per day. The user sets the maximum volume of water  allowed for each time period and if the maximum volume  of water is exceeded in a given period, for example when  a water pipe bursts in the night, the water supply will  automatically be shut off, protecting the building.

    During active construction

    During construction, a designated site representative with  responsibilities for adherence to the quality plan should be in  place. This designated site representative will be responsible  for development and implementation of the quality plan and  for its continual updates and improvements throughout the  project. It is critical that subcontractors work be included  in the QA/QC plan and that a “no defects“ policy is  communicated to all subcontractors. This policy should  be reinforced through inspections, documentation and  regular meetings. Specifically review the coordination  of subcontractors‘ scopes to ensure that no waterproofing  details have been overlooked.
    • Dedicate a team to focus on water prevention
    • Track and monitor problems and repairs
    • Train employees and subcontractors about quality standards
    • Establish a weekly check list to mitigate water issues, and close out all issues weekly
    • Mock-up all critical waterproofing systems prior to construction and discuss critical building system details and inspection concerns
    • Undertake frequent testing, and if a problem is found,  address it immediately
    • Never pay for work with waterproofing issues unresolved

    The building‘s structure should be fully enclosed, with all  windows, doors, walls and roofs complete prior to the  installation of finishes (never allow scheduling pressures  to modify this sequence). Once the roof is installed on your  construction project, conduct extensive water tightness  testing. After this testing has been performed, maintain a  roof free of debris during construction, and ensure regular  inspections are carried out to identify any potential problems.  If there are any problems, quickly address and repair them  before damage occurs.

    In addition to water-tightness testing, make sure that fire  protection systems are hydrostatically tested per  requirements of the most recent edition of NFPA 13 “Standard  for the Installation of Sprinkler Systems,“ and monitor for  leakage during testing. In addition, air pressurisation testing  of all piping systems should be performed prior to charging  with water, even if the system passed a hydrostatic test  previously. Always charge piping systems by zone and not  with all valves open. This will minimise the chances of a large  unnoticed water release. When charging piping, establish  personnel whose sole responsibility is monitoring piping  systems for at least the first 24 hours.

    Take action during or after an emergency

    To ensure that prompt and proper action is taken during an  emergency, a formal Severe Weather Disaster Plan should  be developed. This should:
    • Describe duties and responsibilities in case of a major leak
    • Describe duties and responsibilities in case of severe  weather events
    • Include all possible scenarios and a specific course of  action for each
    • Delegate one person to be in charge that will take control  during an emergency
    If structural failures occur, such as cracks or fissures,  as a result of settlement or displacement due to major  leaks/water damage, contact the structural and  geotechnical engineer for advice immediately, rather  than making aesthetic corrections to the structure. During  construction, prevent the accumulations of snow and ice to  prevent structural failures and water infiltration, especially  when the structural system is not fully established. Provide  security personnel with a list of who to call 24/7 in the  event of an after-hours water release or emergency.
    © Getty Images/Foster.r

    Post construction close out

    During the project close period, it is important to maintain  a dedicated check-list team, and reserve them for check-list  related repairs. This ensures that adequate resources exist  to close the project properly. Address the check-list items on  a weekly basis to ensure that only a week‘s worth of check-list  items remain at the end of the construction period.  

    Maintain a team that can respond quickly to warranty issues, and resolve all water issues as soon as possible and  no later than 48 hours. Take all “good faith“ efforts to prevent  further damage if water is discovered. Check list should take  account of:

    Unsecured building openings

    • Door and window openings
    • Roof openings building envelope
    • Door, window and exterior wall deficiencies
    • Roof, gutter and window flashings
    • Damp-proofing and waterproofing

    Water delivery or drainage system failure

    • Plumbing system
    • Fire protection system
    • Mechanical system
    • Drainage system

    Site drainage problems

    • Improper drainage away from excavations and  building structures
    • Inadequate retention ponds

    Subsurface drainage problems

    • Drainage issues

    Foundation and structural element problems

    • Cracks/fissures in waterproofing structures
    • Separation of building envelope elements
    • Flooded/undermined excavations
    • Excessive/premature loading

    Material storage problems

    • Water sensitive equipment installed improperly
    • Failed just-in-time delivery resulting in improper storage
    References The UK CAR Underwriters Group/CIREG Best Practice Guidance on the Avoidance of Water Damage on Construction Sites 4th Edition June 2015 NFPA 241: Standard for Safeguarding Construction, Alteration and Demolition Operations 2019 Edition Disclaimer: The guidance in this document refers to industry best practice loss control advice. Adoption of the advice contained within this document does not imply  compliance with industry, statutory or HSBEI guidelines, nor does it guarantee that water related losses will not occur. HSB-LCE-RGN-003 Rev:0 Date: 7/06/2013

    Construction insurance solutions and inspection services

    We have a comprehensive range of construction insurance products covering all aspects of projects across the UK and Ireland.

    Our engineering inspection services also help customers to maintain workplace equipment safety, optimise the efficiency of a vast range of plant and equipment, and comply with applicable health and safety legislation.