Evaluating Water Leakage of Building Walls
Posted on Sep. 2, 2023 / Subscribe 0
Water intrusion through the building envelope is a significant factor in insurance claims and construction litigation. Professionals rely on structured methodologies, such as ASTM E2128, to assess the sources and impacts of water infiltration. This discussion outlines the steps and considerations for evaluating water leakage in building walls, focusing on systematic investigation, diagnostic testing, and detailed reporting.
The building envelope is the physical barrier between the exterior and interior environments of a building. It consists of materials that make up the foundation systems, exterior wall assemblies, windows, doors, roofing systems, and various penetrations through the envelope. Similarly, the exterior wall, a component of the building envelope, is an assembly of materials that need to work as a system to provide protection against weather elements including water intrusion. The transitions, connections, and compatibility between these materials is critical to ensure that the building envelope functions as intended. Workmanship plays a vital role in wall construction, with attention to detail by designers, contractors, and third-party inspectors being essential for the successful execution of the assembly. Deficiencies in design or workmanship can compromise the system, allowing water intrusion. Depending on the size of the openings and the duration of exposure, such deficiencies can lead to deterioration and failure, ranging from minor finish distress to significant structural damage.
Building codes, referenced standards, regulations, manufacturer guidelines, and industry standards set criteria for design, function, and construction of building systems, including exterior walls. As a primary weather barrier, exterior walls must be designed and built to withstand environmental elements, including water intrusion. The following International Building Code (IBC) provision establishes this requirement for exterior walls in paragraph 1402.2 Weather Protection:
“Exterior walls shall provide the building with a weather-resistant exterior wall envelope. The exterior wall envelope shall include flashing, as described in Section 1404.4. The exterior wall envelope shall be designed and constructed in such a manner as to prevent the accumulation of water within the wall assembly by providing a water-resistive barrier behind the exterior veneer, as described in Section 1403.2, and a means for draining water that enters the assembly to the exterior. Protection against condensation in the exterior wall assembly shall be provided in accordance with Section 1404.3.”
The IBC also contains numerous references to standards that are used to provide requirements for materials and methods of construction. ASTM International, previously known as American Society for Testing and Materials, is a standards organization that develops and publishes technical standards for a wide range of materials and services. Certain ASTM standards, that are referenced in Chapter 44 of the IBC, are an enforceable extension of the code.
ASTM E2128 Standard Guide for Evaluating Water Leakage of Building Walls is a guide utilized by professionals for evaluating building walls. This standard outlines a practical framework to analyze deficiencies to achieve a comprehensive understanding of defects, such as water leakage. It is important to note that this standard utilizes the approach for recreating known water infiltration concerns and is not a standard for testing design or product specifications.
Façade Types and Drainage
Evaluating wall leakage requires an understanding of the wall system design and its climatic influences by building professionals who evaluate this leakage. Wall assembly types can be described in two broad categories: Barrier Walls and Drainable Walls or a combination of these systems.
The Barrier Wall System utilizes the skin of the building as the primary and only line of defense against exterior water intrusion. There is no allowance for water management. This type of wall assembly relies on initial quality of construction as well as regular maintenance over time to keep a watertight skin. Examples of this cladding assembly may include precast concrete, barrier EIFS, and mass wall types.
The Drainable Wall System typically has two lines of defense against water intrusion. The cladding is a rainscreen with a drainable space behind it. The drainage plane contains the true WRB (Weather Resistive Barrier). Allowances are typically made for water management such as weeps or holes to allow water to drain or escape the system. Examples of this cladding assembly include conventional stucco, siding, drainable EIFS, and brick veneer.
Water intrusion through building wall assemblies can migrate from various sources. The primary source of water on the exterior envelope is precipitation, wind-driven rain, and water vapor transmission. E2128 describes water intrusion hierarchy:
- Incidental water. Unplanned water infiltration that penetrates beyond the primary barrier and the flashing or secondary barrier system, of such limited volume that it can escape or evaporate without causing adverse consequences.
- Water absorption. A process in which a material takes in water through its pores and interstices and retains it wholly without transmission.
- Water infiltration. A process in which water passes through a material or between materials in a system and reaches a space that is not directly or intentionally exposed to the water source.
- Water leakage. Water that is uncontrolled; exceeds the resistance, retention, or discharge capacity of the system; or causes subsequent damage or premature deterioration.
- Water penetration. A process in which water gains access into a material or system by passing through the surface exposed to the water source.
- Water permeation. A process in which water enters, flows, and spreads within and discharges from a material.
ASTM E2128 Methodology
Similar to the scientific method, E2128 follows a structured, sequential approach to collecting information and establishing facts for water leakage analysis. The methodology involves investigating specific leak-prone locations, interviewing building occupants and firsthand observers, correlating historical leak occurrences with building features and environmental conditions, and developing hypotheses about the causes of water intrusion. The guide’s evaluation process utilizes an empirical method of seven steps for gathering and analyzing information as follows:
- Review of project documents
- Evaluation of design concept
- Determination of service history
- Inspection
- Investigative testing
- Analysis
- Report preparation
Review and Evaluation of Project Documents
The first step, Review of Project Documents, including but not limited to plans, details, specifications, and submittals, involves a detailed examination of available records to gain insight into the intended design, materials, and construction details of the building envelope. This step helps identify potential inconsistencies between design intent and actual construction, providing a foundation for further investigation.
Service History
The service history should include interviews and survey of the building users, interview of the maintenance staff and vendors, and any other first-hand observers. Obtained information should include dates of events, weather conditions, locations of leaks, frequency of leaks, and any attempted repairs and investigations.
Inspection
A checklist may be prepared in advance of the inspections. Equipment such as measuring devises, levels, and photo and video cameras should be used for documentation. Field inspections will include, but not limited to, observations such as sealants, flashings, weeps, drainable systems, material conditions, transition of materials, freeze-thaw damage, deterioration, material failure, repair attempts, workmanship, and water related damage to finishes.
Investigative Testing
The objective of testing is to identify the leak paths through simulation of the weather events that produced the reported water penetrations. Like the scientific method, testing can be used as a means to verify and extend hypotheses reached during the document review and inspection phases. Employing testing before completing the preceding steps will be disadvantageous to the test, may contribute to spoilation of existing conditions, and lead to erroneous conclusions.
Testing and sampling locations can be limited to where typical problems occur, saving the time and expense of testing areas unlikely to have problems. Testing to the environmental conditions at which the leak occurred, within available means, is important to the success of the leak investigation effort.
Analysis and Report Preparation
While strictly adhering to ASTM E2128 may not always be practical or necessary, using its methodology as a framework ensures an investigation grounded in scientifically valid principles. Findings and conclusions should be rational, well-supported by acquired data, and defensible. If conclusions cannot be fully substantiated by sound scientific principles, further investigation may be recommended.
The information contained in the report should be comprehensive and include components such as: purpose, description of property, documents reviewed, site inspections conducted, standards and breach of these standards, testing methods and observations made, findings, conclusions, and the identification of the evaluator. As the report will serve as part of the project record, it should be a self-contained document. If the evaluation results are inconclusive, the evaluator can present options for further testing.
Rules of Evidence
Following a scientific approach to investigation and evaluation, such as ASTM E2128, ensures compliance with current rules of evidence for forensic investigations when properly implemented. The Federal Rules of Evidence (FRE) govern the admissibility of evidence in U.S. federal courts, requiring that information be relevant, reliable, and scientifically valid. Most state courts follow similar rules, with some variations. Adhering to a structured methodology like ASTM E2128 strengthens the credibility and reliability of forensic findings, supporting their admissibility in legal proceedings. While New Jersey does not directly follow the FRE, forensic investigations conducted under ASTM E2128 can still align with NJRE if they adhere to generally accepted scientific principles. This means that systematic, well-documented methodologies remain essential for admissibility in court.
Elina Shchervinsky, AIA, NCARB, LEED AP
EXPERT FORENSIC ARCHITECTURE, LLC
expertforensicarchitecture.com
Expert Forensic Architecture, LLC (Expert Forensic) was founded by Elina Shchervinsky, AIA, a Forensic Architect and Expert Witness. Expert Forensic collaborates with a diverse team of experts and consultants to thoroughly address building investigations.
Elina is a Registered Architect in New Jersey, New York, Pennsylvania, Connecticut, Virginia and Florida with over 30 years of experience in architecture and construction.
Her extensive career spans the design and construction of a wide range of building types, including schools, medical facilities, residential and industrial buildings, parking garages, airports, municipal structures, warehouses, retail spaces, laboratories, restaurants, mixed-use developments, and office buildings. Her expertise covers new construction, additions, renovations, alterations, and remediation projects.
Elina is the Past-President of the Central New Jersey Section of the American Institute of Architects (AIA) as well as the Chair of the AIA CNJ Codes and Standards Committee. Her expertise is the subject of the AIA CNJ Webinar “Forensic Architecture and the Standard of Care.” Her commitment to the AIA was recognized on multiple platforms including the article entitled “Shaping An Inclusive Horizon.”
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