This is a follow-up to the long-term durability test at the University of Texas I posted about last week. Today, I am talking about how well a membrane seals around nail holes, specifically how it performs in an ASTM test that manufacturers subject their products to in order to show they meet a standard of "waterproofing." As a part of the Weather Resistive Barrier (WRB) testing, the UT team ran its own version of this ASTM – D 1970 test, which was created for roofing membranes that guard against ice dams and the leaks that occur when ice is forced under the shingles, then melts. Well, it turns out this test is pretty tough to meet. I heard from the UT team that the test labs with the official ASTM results apparently only publish the "passing" tests and not the failed ones.
So, which is the one that actually passes in the video? Only Tremco's ExoAir 220 actually passed the test run by the UT Durability lab. This Fluid Applied (thick mil) WRB was the only one that successfully sealed around the backed-out nails and kept water at bay for the required period of time. This is only one test, but that's a pretty big win for the Tremco WRB.
I'm working on a Journal of Light Construction article that will be published next month on the topic of WRBs and the good/better/best methods for using them on your project. Stay tuned.
To read Beth Anne Feero's article in Construction Specifier, click here.
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