Investigation Of Water Damage Claims For Subrogation Potential by Chris Shiver, PE and Phil Chapski, PE, Cerny and Ivey Engineers, Inc., Norcross, Georgia Water entry into homes and businesses is the cause for a large number of insurance losses and claims. Though many of these claims are attributable to natural catastrophes, a large number are the result of building or site construction weaknesses, or deficiencies in installed fixtures and appliances. This article will review proper engineering/ technical investigative methods for determining the causes of water damage and whether or not any outside party may be responsible. Included will be evaluation of civil engineering issues to determine whether water is entering the structure from outside due to a building envelope failure or improper control of stormwater at the site. Of particular interest for that type of evaluation is establishing whether the water entry is due to original or renovation construction defects, or is instead attributable to failure to properly maintain the property. We will also address mechanical engineering reviews required to establish whether water damage is due to failure of an internal plumbing system and/or HVAC component or appliance. In those instances, the possible root cause contributions of hardware manufacturing, installation and use/abuse will be addressed. A large number of home and business water damage claims are found to be the result of storm or groundwater entry. In this article, we will focus on long term water entry causes, rather that sudden water intrusion resulting from major storm flooding or high wind events. In most instances, professional inspection after a structure is exposed to a severe storm event can differentiate between damage resulting from rising water and/or exposure to high winds/wind driven debris, versus damage that preexisted the storm. In some instances, it will also be discovered that severe storm exposure actually initiated leakage but that the ultimate cause was weakness in the cladding systems due to improper installation, failure to follow local codes (especially in hurricane zones) or improper maintenance. The common water entry locations in most building envelopes include roofs, walls and foundations. Roofing Roof design includes sloped and flat (which actually have minimal slopes) systems with differing types of coverings. On sloped roofs, stormwater flow needs to be managed with adequate gutters, downspouts and drains to protect walls and foundations from stormwater infiltration. On flat roofs, proper setup of drains, scuppers and gutters is additionally critical for preventing ponding of stormwater on the roof which can cause leakage and even structural overload and collapse. With any roof, water flow management system, proper design and maintenance for prevention of clogging by natural debris is crucial. Roof coverings include shingles, shakes and tiles (sloped roofs), and membrane, or built up systems (flat roofs), and metal panels. With all of these systems, proper installation in accordance with manufacturer s instructions is crucial for leak prevention, especially at transition points such as peaks, valleys, penetrations and wall interfaces. All roof coverings (even metal) are subject to deterioration over time, and therefore require regular inspection, maintenance and eventual replacement. In some instances, design of roof and attic insulation and ventilation systems can contribute to the premature deterioration of roofing materials or leakage. Most roof failures and leakage (where not caused by exposure to severe windstorm) are due to
shortened life failure from improper application or installation, or late in life deterioration from normal aging and weathering. Figure 1: Long term water damage due to metal roof ridge cap leak.
Figure 2: Synthetic stucco (EFIS) wall cracking and water entry. Exterior Walls Investigation of leakage into or through building walls starts with evaluation of the cladding or siding system. Generally, the outer material type and installation should either fully prevent moisture penetration, or be designed so that any water entry is drained away before it can affect or penetrate further into inboard wall materials. Of crucial importance are proper installation, flashing and sealing of wall penetrations, especially doors and windows. Wall cladding and door and window products are available in a wide variety of material types and qualities. The choice of materials, how they are finished, and ultimately whether they are properly maintained are all crucial to how long these building elements will resist weather deterioration and water penetration. Within building walls, the choice and placement of insulation materials and vapor barriers are also crucial for moisture control. Depending on the climate where the structure is located, improper design or installation of the material layers in a wall can result in water or condensation accumulation in wall cavities or soaking of absorbent elements such as fibrous insulation. In many cases, recent attempts to comply with more strict energy efficiency specifications or codes have resulted in ill conceived wall constructions that encourage damaging water accumulations over time. Foundations
A crucial but often overlooked area for preventing water or moisture entry into buildings is proper design, installation and maintenance of foundation systems and their supporting soils or stone. Buildings supported on concrete slab type foundations may require edge treatments, moisture barriers and even insulation appropriate to the climate and soil conditions, to prevent damp or wet floors and subsequent damage to floor coverings and contents. For buildings supported on foundations, walls, piers and footings, a crucial factor is the treatment and usage of the below grade spaces, which can range from a bare soil crawlspace to a fully finished and airconditioned basement. In each of these instances, the choices of foundation wall materials and finishes, vapor or moisture barriers, ventilation (for un conditioned areas) and drainage provisions are crucial for prevention of unwanted water intrusion. In addition, proper selection of subfloor materials above an unconditioned space can be important in preventing water entry into the occupied spaces and moisture damage and rot in the subfloor. For all foundation systems, a proper combination of waterproofing, drains around the exterior and routing of roof drains/downspout flows away from the structure, are crucial factors in preventing water problems. In some instances, sump pumps may be installed to remove foundation/ basement level water accumulations, especially as a corrective measure in existing buildings. However, it is generally more desirable to take the steps necessary to prevent water entry, rather than to rely on proper operation and maintenance of an often overlooked mechanical feature to prevent water damage.
Figure 3: Foundation water leak and subfloor damage. Water Flow Where water entry or damage has been claimed, particularly in the lower elevation levels of a structure, a look at the overall management of stormwater flows on and around the property is an essential part of any expert evaluation. Water flows during heavy rainfall generally need to be directed away from buildings by proper use of grading, surface water channels (swales) or catch basins with underground drains. On sites (especially commercial properties) with large impervious surface areas (paved areas such as parking lots) water flow management should be designed by a qualified engineer in accordance with applicable codes, and flow delay features such as retention ponds may be required to prevent flooding or overloading of storm drains. On any site, the proper direction of drainage features to public storm drains or natural watercourses is crucial for protection of both the subject property as well as neighboring properties. A proper evaluation of a water damage claim on a site will include a determination as to whether any flows originating from that site are contributing to the problem, as well as responsibility for managing those flows from other properties.
Figure 4: Fixture connection hose fitting corrosion failure. Piping Systems
In many cases, water damage within a structure is from an internal source, such as a plumbing or other mechanical feature. By far, the largest number of failures involve the pressurized water supply and distribution equipment, which is required in essentially all occupied buildings. Evaluation of such equipment should include the structure s water feed from a utility or well source. Most systems are utility fed, which means that in many cases the function and condition of generally required features such as meters, pressure regulators and backflow prevention can be of great importance in diagnosing leak problems at those locations or elsewhere in the building. Piping systems for pressurized water can be fabricated from a number of different approved plastic and metallic materials, each of which requires adherence to proper procedures during installation. Inspection of these systems requires familiarity with the proper methods and code requirements for joining, supporting and routing each type of material. Piping and connection failures can also result from failure to account for or correct water chemistry, or application issues that may cause the material to corrode or otherwise deteriorate. Many failures occur where plumbing fixtures and appliances are connected to the piping, especially where flexible hoses are utilized. Component failures within various appliances are frequently identified as the source of many damaging water leaks in particular, a fairly high failure rate for various types of in line water filter system casings has been observed. Pipe freezing causes many water losses, generally due to failure to properly rout or trace lines, or reliance purely on insulation alone for protection. Circulating water in piping systems can be used to prevent freezing, but only if the pumps or other means to maintain water flow are reliable even with the building closed or during power outages. Hot Water Systems Hot water systems have special features and requirements (certain types of plastic piping cannot be used), including leakage issues related to water heaters. Traditional steel tank water heaters are generally destined to suffer tank failure and leakage over time, with the actual life span depending on manufacturing quality, proper installation and maintenance practices. With water heaters, and many other appliances where leakage or spillage may be expected, proper provisions for water collection and drainage are important. Generally, all plumbing installations include a waste, drain and vent system, which is also covered by detailed code provisions. While leakage from these unpressurized systems can occur, more common losses involve clogging or overloading that result in backup of wastewater into building spaces through fixtures and drains. Backups can be due to system design issues, but are also frequently attributable to poor usage and maintenance practices including addition of improper or excess solids through toilets or drains. Most commercial kitchen installations require properly designed and integrated grease interceptors to prevent fats, grease and oil from congealing and clogging waste systems. Many of the more spectacular and costly waste backups observed are caused by failure to properly setup and maintain grease interception systems.
Proper setup of venting for waste systems can also be crucial for effective drainage and odor prevention, especially in large structures. Many below grade plumbing fixtures require lift pumps for proper waste flow failures in that equipment may often cause insidious damage within hidden spaces, often manifesting itself by the presence of objectionable smells. Plumbing Plumbing systems in many larger commercial or industrial buildings often are not simply scaled up in size, but involve water pumping, regulation, treatment and heating equipment quite different from small residential and other structures. Highrise structures in particular are frequent scenes of massive water losses involving subtle and complicated failures within plumbing systems that may be challenging to locate and analyze. These systems also include large diameter pressure piping with the result that some loss sources are both easy to locate and dramatic. Many larger structures (and with increasing frequency, smaller buildings and homes) include waterbased fire protection systems. These systems frequently feature piping and connection methods differing from other plumbing, as well as unique control, alarm and test features. In addition to the failure modes common to all water piping, these systems are also prone to occasional false actuation and water release from intentional acts and equipment malfunctions. Fire protection systems in particular have very stringent requirements for frequent maintenance and testing, which if properly performed should reduce the opportunities for damaging leakage. Mechanical Mechanical equipment that should be inspected during water damage cause evaluation includes heating, ventilating, air conditioning and refrigeration features (HVACR). In many buildings, these systems generate evaporator coil condensate during the cooling season, which must be drained or pumped out of the building, or into its drainage system. Condensate drip pan leakage (especially steel pan rust through) and pump failures are two frequent causes of water damage. In the last few years, there has been a resurgence of hyrdronic heating systems (particularly in homes), where hot water (or steam) is piped from a central heater/boiler to radiators, fan coils or underfloor tubing in each room. This obviously increases the potential for damaging water leakage in buildings, as well as adding to the knowledge required to properly evaluate these claims. Also increasing in popularity in homes are water sourced heat pumps, which include a circulating water loop entering and leaving the structure. Many larger structures also utilize hydronic systems for heating and cooling, with refrigerant cycle driven chillers and cooling towers used for heat removal. In addition, some small or large systems may include active humidifiers or dehumidifiers, which require either pressurized water supply or water drainage features, creating yet another source for potential leakage.
Some buildings may also suffer excessive internal humidity and even water accumulation due to improper design, installation, operation or maintenance of their space conditioning systems. Building HVACR equipment should be subject to regular (start of each heating/cooling season) inspection and preventive maintenance to maximize its efficiency and identify deterioration or possible impending failures. Conclusion In summary, water damage within buildings and affecting properties can potentially be from a number of sources and causes. Though technological improvements in many building components have reduced the potential for some types of failures, new products and features have also introduced additional failure modes or increased the opportunities for certain types of water leaks. Proper evaluation of these failures by qualified and experienced engineers and other appropriate professionals holds the greatest promise for accurately determining the origin and cause of damage caused by water or moisture. This approach also is the most likely to produce scientifically supportable findings and results, which can be used to justify assignment of responsibility for the consequences of a water loss to appropriate parties. Choosing a firm that can provide both a registered mechanical engineer and a registered civil engineer as needed for water loss evaluation ensures that all potential causes can be properly and impartially considered. This article appeared in the Winter 2007 Issue of the NASP Subrogator. NASP