Can We All Just Get Along? Ensuring Compatibility Among Liquid Applied Sealants and Flashing
By Aaron Blom
A study by RDH Building Engineering examining leakage in a wide variety of window types and assemblies showed that the window-to-wall interface was the most prevalent leakage path for all windows tested, carrying a high risk of consequential damage to buildings.
Preventing air and moisture intrusion includes selecting sealants and flashing materials that meet performance requirements for the project and ensuring that those products are compatible with one another.
An updated version of AAMA 713, Test Methods to Evaluate Chemical Compatibility of Freshly-Applied Sealants with Freshly-Applied Liquid and/or Self-Adhered Flashing Materials, will publish in 2024, representing a significant change in scope to the document.
Is It Safe to Cut Corners?
It’s common for field installers to apply flashing materials to sealants without allowing for the manufacturer’s recommended full sealant cure time. For this reason, FGIA’s Flashing Committee set out to address an important question: Under those circumstances, are these products compatible with one another? AAMA 713 was updated to verify that this reduced cure time does not affect compatibility. Furthermore, the upcoming republication of AAMA 713 also includes testing for compatibility of liquid-applied flashing with both sealants and self-adhering flashing materials.
The test methods describe a laboratory screening procedure for evaluating the chemical compatibility of sealants, liquid-applied and self-adhered flashing materials, intended for use in fenestration installations. Compatibility is only part of the equation for a high-performing installation. Proper installation of fenestration products per manufacturer’s recommended installation instructions or other industry-accepted installation guidelines, such as InstallationMasters®, is critical for ensuring performance.
Chemical compatibility is limited to observed visual effects, including drain-down, cracking, blistering, swelling, and debonding of the sealant, liquid applied and self-adhered flashing materials and more. These test methods are intended for the installation of fenestration products.
It’s important to note that the tests in AAMA 713 do not address the performance requirements for these products. These are tested per AAMA 800, Voluntary Specification and Test Methods for Sealants, AAMA 711, Specification for Self-Adhering Flashing Used for Installation of Exterior Wall Fenestration Products, and AAMA 714, Specification for Liquid Applied Flashing Used to Create a Water-Resistive Seal Around Exterior Wall Openings in Buildings, respectively.
This laboratory screening procedure provides a basis for the proper selection and specification of sealants and adhered flashing material.
To simulate component compatibility and performance over time, elevated temperatures are used to accelerate aging. The test duration is three weeks and product/system combinations can be tested to achieve compatibility in three progressively rigorous categories.
Within 30 minutes of preparation, all samples should be placed at a 60° to 70° angle into the oven at the specified exposure temperature. Samples are aged in the oven for seven days, then removed for evaluation. Samples are evaluated within 30 minutes from time of removal. If there is no evidence of incompatibility, the samples are placed back into the oven and evaluated again after an additional 14 days. The test can be terminated if any evidence of drain-down is observed, which would indicate incompatibility.
Following these guidelines helps protect against air and moisture infiltration, and enhances the success of a building enclosure’s performance. For further guidance, you can find a copy of AAMA 713, an FGIA document, in the FGIA Online Store and the updated publication will be available soon.
Aaron Blom is technical training specialist for the Fenestration and Glazing Industry Alliance (FGIA).
ablom@fgiaonline.org
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