By Shauna Sproul
Field testing of building exteriors for water penetration, frequently simply called “water testing,” is essential for identifying manufacturing and construction defects in windows, doors, skylights, and other openings in the building envelope. For example, a window might leak due to problems with installation of waterproofing and perimeter sealant details, or because of improper materials or methods used by the plant during manufacturing.
Many clients come to us for one-day water testing, conducted upon the completion of construction. While such tests are certainly useful and productive, earlier engagement in the process can help contractors and building owners avoid costly, more complex issues frequently uncovered during one-day tests.
Water testing determines the resistance of manufactured windows, curtain walls, skylights, and doors to water penetration. Proper water testing methodology follows the protocols set forth in the American Society for Testing and Materials (ASTM) E 1105 standard. Under that standard, water penetration failure occurs when water leaks beyond a plane parallel to the vertical plane of the assembly’s innermost projection, not including interior trim and hardware.
While the test is a field version of laboratory certification tests and simulates the conditions of a wind-driven rain storm, laboratory testing itself of glazing systems and other building assemblies cannot reflect field testing results. Materials and methods used in construction can significantly affect their performance in actual use. Events occurring between shipping and installation as well as environmental influences can all have a negative impact on component and system performance.
How it’s done
Water testing measures penetration by applying water to the outdoor face and exposed edges of the tested assembly with a static external air pressure higher than the pressure on the indoor face. Not only will it determine resistance of assembly components themselves, it can also reveal leakage between those assemblies and the surfaces in which they are installed. While a manufactured component may successfully meet ASTM E 1105 water testing criteria against leakage into the building itself, water may penetrate an assembly, leading to degraded performance of materials.
Water testing is typically conducted by sealing a chamber to the interior face of the assembly tested, then exhausting the air from that chamber to produce pressure differentials similar to those produced by weather. A rack of calibrated water nozzles sprays water at the proper rate on the exterior surface. The air pressure differential may be uniform (constant) or cyclic (varied). It’s important to note that air pressure varies greatly across the building envelope and the water testing methods applied should incorporate an understanding of that variation. Though water testing uses similar equipment, air infiltration measurement is not included as part of the procedure.
When to test
Water testing may be conducted any time between initial assembly installation and construction completion. However, earlier and repeated testing is advisable for multiple reasons. Tests conducted upon initial installation provide easier inspection of interior surfaces for penetration and to identify the precise point(s) of penetration. More importantly, with early testing, fabrication and installation problems can be discovered at a time when corrections are more easily made and at much lower expense since no interior wall components must be removed and replaced.
While building codes may not require it, every new construction project should be water tested regardless of size. No project is too large or too small. Many smaller projects don’t incorporate water testing simply to keep construction costs lower. Any financial advantage disappears, however, if windows or doors start to leak and water testing reveals hidden problems. The cost of water damage and remediation can greatly exceed the cost of early testing and consultation.
The ideal time to start water testing is when the first few glazing systems are installed. Not only are problems more easily detected, design and potentially recurring issues can be corrected going forward. Contractors and owners who rely on one-day water testing only when the project nears completion may be unnecessarily adding risk and cost to their construction projects.
Better still, engaging the full scope of services of a building envelope consulting firm like GCI can help identify water penetration and other building envelope issues at the planning and specification stage. It simply makes more sense to solve water issues in a project’s development and before testing, not after leakage has occurred in a nearly completed building and added water damage to the combined problems. Some potential leakage problems can be solved before windows and other assemblies have even been ordered.
The ASTM Standard is used for both the one-day testing and in the testing we would do on a full scope project, yielding the same results. The concern is we cannot always fix the issues easily with a one-day test because the building is closed up and all the windows have already been installed. In a full scope job we would test early enough to get the issues resolved before all the windows would go in.