Testing Building Components for Water Infiltration

By: David M. Kenney, AIA, NCARB
In August of 2020, Aston Township, Pennsylvania, published an online article regarding an August 4, 2020, severe wind, and rainstorm event. The article also described a second severe storm later that week on August 7, 2020. These two back-to-back severe storm events resulted in large amounts of rainwater surface runoff, as the ground was already saturated from other rain events that occurred prior to the first storm on August 4th. During those events stormwater entered a nearby school gymnasium exterior door and damaged the gymnasium floor. The article stated,
Aston Township was hit by two back to back severe storms during the week of August 3, 2020. The storm which occurred on Tuesday, August 4th resulted from the remnants of Tropical Storm Isais and was widespread over the entire county. The storm on Friday, August 7th was more localized, with Aston and other western Delco communities hit the hardest. The storm on Tuesday dropped 4.8 inches of rain over a 6-hour period which would be between a 50 and 100-year storm event. The Friday storm resulted in 3 inches of rain over a 1-hour period which would be classified as a 100 and 200-year storm event. This was based on the reading at the USGS Chadds Ford River Station on the Brandywine so the actual rainfall in Aston may have been higher. The fact that storms of this magnitude both occurred a few days apart is unprecedented.
Putting this in perspective, Friday’s storm was on par with Hurricane Sandy in 2012 given the large amount of rain in the short period of time… The fact that these large storms were “back to back” added to the problem and then created other issues. The ground was already saturated from all the rains received this summer, even prior to the first storm on the Tuesday. Retention basins that are meant to hold storm water and release it slowly for several days after a normal storm, did not have sufficient time to completely discharge between Tuesday and Friday. This is what happened here. [Ref.: https://astontownship.net/storms-of-august-4-and-august-7-2020-and-the-impact-on-aston-township/]
Historical weather data showed that the August 4th storm had wind speeds up to 30 mph with gusts up to 44 mph. Winds were primarily from the WSW, WNW, N and NE, generally the direction that the gymnasium door faced. During the August 7th storm, wind speeds reached 28 mph with gusts up to 33 mph, and came from the NNE and NE, again directed toward the gymnasium door [Ref.: weatherunderground.com].
The exterior concrete walkway outside the gymnasium door drained away from the building and the doorway was protected by a deep porch roof. There were no reported water intrusion issues at the subject door in the six years since the school was constructed up to the back-to-back extreme weather events during the week of August 3, 2020. As stated in the Aston Township article, the fact that storms of this magnitude both occurred a few days apart is unprecedented. These two back-to-back extreme weather events with significant amounts of precipitation and high wind speeds and gusts directed at the gymnasium door overwhelmed the door’s ability to resist stormwater infiltration.
However, there are methods to test building fenestration systems such as doors, windows, and skylights to determine if those materials have been installed in a matter that likely will prevent environmental moisture infiltration. AAMA 503, Voluntary Specification for Field Testing of Newly Installed Storefronts, Curtain Walls, and Sloped Glazing Systems is a field-testing guide developed by the American Architectural Manufacturers Association (AAMA). AAMA 503 provides specific details for testing procedures to ensure air and moisture penetration is minimized in newly installed fenestration systems.
AAMA 503 is based on guidelines established by the ASTM International document, ASTM E 1105, Standard Test Method for Field Determination of Water Penetration of Installed Exterior Windows, Skylights, Doors, and Curtain Walls. ASTM E 1105 is used for water penetration testing, and ASTM E 783, Standard Test Method for Field Measurement of Air Leakage Through Installed Exterior Windows and Doors, is used for air infiltration testing.
AAMA 503 states that the testing shall be performed as soon as practical after the fenestration system is installed. The testing also must be performed before the installation of gypsum wall board or other interior finishes to allow visual verification of the test results. With a large project, early testing can identify a design or installation issue and therefore avoid later costly repairs. If a test specimen fails, the contractor, fenestration system installer, or the product manufacturer will have an opportunity to make repairs. After those repairs are completed, the test specimen should be re-tested to verify the adequacy of the repairs.
If the building is occupied, or the installation is more than six months old, or after occupancy it is discovered that certain installed fenestration products exhibit enjoinment leakage, AAMA 503 can no longer be used to test those products. Instead, AAMA 511, Voluntary Guideline for Forensic Water Penetration Testing of Fenestration Products shall be used. AAMA 511 states,
Building damage caused by uncontrolled water penetration through exterior walls is a serious concern of owners, contractors, architects and product manufacturers. Often, improper or inadequate leak investigations result in investigators misidentifying the source of water penetration through the exterior wall.
In many cases, this error results from observations of water penetration at or near a fenestration product opening that may originate from the surrounding construction. In other cases, the water penetration is a combination of sources which may be inclusive of the fenestration product assemblies. A systematic forensic investigation of the water penetration is required to determine the actual source of the leak.
The purpose of this AAMA Voluntary Guideline is to provide specific information to assist industry professionals in selecting the appropriate adaptations to the existing testing standards for application to field investigations of fenestration products. ASTM E 2128, [Standard Guide for Evaluating Water Leakage of Building Walls], provides the foundation for field investigations of water leakage in building walls. [AAMA 511] is designed to provide supplemental guidance and highlight required information and actions regarding fenestration product investigations.
ASTM E 2128 is a more comprehensive standard guide for investigating building water infiltration issues and determining the root cause or causes of those issues. ASTM E 2128 provides a comprehensive methodology for evaluating water infiltration. In this regard, ASTM E 2128 is not limited to building fenestration products. ASTM E 2128 describes methods for determining and evaluating causes of water intrusion of exterior walls. It defines the building exterior wall as a system. Therefore, it includes an investigation of the exterior wall cladding, the wall structural components, the windows and doors, and the interior finish systems.
ASTM E 2128 provides a methodology for the systematic approach to an evaluation, including details on the initial evaluation, reviewing the building’s service history, identifying the physical symptoms, visually inspecting reported infiltrations, recreating leaks while simulating normal rainfall, tracing and correlating infiltrations, providing a final analysis, and accurately reporting the investigation and results. ASTM E 2128 covers a variety of investigative techniques, including intrusive, destructive, and non-destructive ways to determine the cause and origin of water infiltration.
CESI has received inquiries that describe ongoing water infiltration events that have been repaired repeatedly, but the building still leaks. Often water infiltration is inaccurately attributed to an incorrect exterior envelope component. Sometimes consultants and repair contractors fail to accurately identify the cause of an active water leak and recommend repairs that turn out to be ineffective in stopping the leak. CESI has investigated hundreds of building water infiltration cases and has the knowledge and experience to determine the cause or causes of a building leak. If you have a case that involves environmental water infiltration of an unknown cause, please consider retaining CESI to perform a comprehensive and science-based investigation to assess the issues and determine the root cause(s) of the infiltration.