Specifying and installing flashing around exterior wall openings

Testing requirements

Tests used in this standard are based on recognized AAMA, ASTM, or other industry-standard tests, which may have been modified. Test procedures and pass/fail requirements discussed in this article are based on laboratory-controlled conditions. AAMA 714 delineates testing requirements for the following performance characteristics:

• Adhesive strength to substrates. Perform a 180-degree peel adhesion test as specified in Section 8.1 of ASTM C794-18(2022), Standard Test Method for Adhesion-in-Peel of Elastomeric Joint Sealants. The substrates tested must be representative of those used in actual construction, but must include at least the following: concrete masonry units (CMUs), mortar substrate, OSB, and plywood.
• Water penetration resistance around nails or fasteners. Similar to AAMA 711, the flashing is applied to OSB, plywood, or exterior-grade glass-faced gypsum board. Next, two fasteners, a galvanized roofing nail and a zinc-plated #8 pan head wood screw, are driven through a slotted vinyl shim, through the liquid applied flashing and into the substrate. An open-ended watertight cylinder encircles the area and is filled with water, and another container is placed under the assembly being tested. After the test period, if water is found in the bottom container, on the fastener shanks, or on the side or underside of the substrate, the test is reported as a failure. This test is performed both before and after thermal cycling.
• Accelerated aging with UV light exposure. A minimum exposure time to UV light is expected before the liquid-applied flashing is covered by exterior facade materials and, therefore, degradation of liquid-applied flashing materials due to UV exposure should be considered. Testing is performed similar to the procedure described earlier for self-adhering flashing and the light source test chambers must conform to ASTM G154 and ASTM G155. After exposure, perform adhesion tests as specified in ASTM C794.
• Elevated temperature exposure. The liquid-applied flashing must remain stable through the thermal exposure expected during the life of the building. Prepared specimens may be classified for three levels of elevated temperature: level 1, 50 C (122 F), level 2, 65 C (149 F), and level 3, 80 C (176 F). After seven days of exposure at the desired level, perform adhesion tests per ASTM C794.
• Thermal cycling/freeze-thaw. Prepare specimens per ASTM C794. The specimen is then exposed to a high temperature for eight hours, followed by a low temperature for 16 hours. This cycle is repeated 10 times and afterward, the specimen must pass an adhesion test per ASTM C794.
• Crack bridging ability. Building settlement, joint movement between dissimilar materials, and thermal cycles will lead to cracks and misaligned joints. The liquid-applied flashing must have adequate elastomeric properties to maintain the water-resistive seal through these movements. Samples are tested using a modified version of ASTM C1305/C1305M-16, Standard Test Method for crack Bridging Ability of Liquid-Applied Waterproofing Membrane.
• Water immersion. Prepare three liquid-applied flashing specimens per ASTM C794. Perform a peel adhesion test per ASTM C794 over one half the bonded length of a specimen and then the specimen is immersed in water for seven days. After seven days of water immersion, a second peel adhesion test is performed per ASTM C794.
• Damp surfaces. This standard also provides a procedure for testing the adhesive bond strength of the liquid-applied flashing when applied to a damp surface. This includes conditioning for damp surface testing, requirements for adhesion bond strength, and testing for water vapor permeability per ASTM E96/E96M-22ae1, Standard Test Methods for Gravimetric Determination of Water Vapor Transmission Rate of Materials’ Method B.