Glass mat substrate and water resistive barriers

Hi everyone,
Hoping for some insight from any other stucco inspectors out there. Today I came across a glass mat substrate with an additional single layer of water resistive barrier. I know that glass mat manufacturers like to say that the fiberglass layer is water resistive, but I can’t find anything specific on if it can be considered one of the required 2 layers of WRB for a stucco application (according to ASTM standards).
My guess is that it can’t, but I was hoping for confirmation.
Thanks!

Contact the Manufacturer and request their Tech Data on the product.

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I agree with Jeffrey, you will need manufacturer information to determine suitability for application. The manufacturer should have an ICC-ESR to reference. There are a few glass-mat sheathing manufacturers with integrated A/WRB materials meeting ASTM and IBC/IRC requirements.

I’m not aware of a glass-mat sheathing that has not went through the pretreatment process that would meet ASTM and ICC

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Thanks Jeffrey, I unfortunately only had access to 1" core samples that I took as part of the stucco inspection, so I couldn’t determine the manufacturer or specific product. Thanks for your response!

And thanks to Robert, too. I appreciate you taking the time to respond