"Everything within the waterproofing membrane"

Partially True.  True: The membrane itself is not included.  Technically, only a percentage of the materials for the credits you are seeking must meet low emitting critera (v4.1).  IE: If you are pursuing ceilings, 90% of the materials must comply to contribute, and with walls only 75% must comply - though it's certainly a lot easier to calculate if you don't have to use the budget method AND you can get a bonus point for tracking at 90% for a min. of three categories.  If your project is v4 and you're substituting v4.1 credits, your materials can utilize v4 testing standards (CDPH Standard Method v1.2-2010 rather than 2017).  The v4 guidebook has some pretty helpful diagrams that really help visualize where they draw the line.  

We also got a response comment that you have to get the actual testing lab data/certificates from the manufacturers. The product data sheets that reference VOC content (distributed by the manufacturers) is not accepted. 

This is making this credit very difficult to collect paperwork at the end of the project, and slows down product approval processes during construction phases, as the contractors and the manufacturers have no clue what you are asking for. We were advised to not pursue adhesives & sealants as well as paints & coatings, and it was great advice as most of those products do not qualify or have proper documentation to support their claims of VOC content.  

Lab results for VOC Content? I get the VOC Emissions testing report, that makes sense, but VOC content? VOC content standards were originially developed to respond to ground level smog concerns. It seems very odd that reviewers would reverse a long practice of accepting VOC content claims from manufacturer's cut sheets.

They have to be talking about the CDPH emissions test report which should report TVOC Emisisons after 14-days. The VOC content listed on a Product Data Sheet is different from this. The manufactuer should be able to report this and provide you documentation if they actually have had their product tested. 

this one has been a bit of struggle for us as well. 

Laboratory's that conduct the tests must be accredited under ISO/IEC 17025 ... and/or ... organizations that certify manufacturer's claims must be accredited under ISO Guide 17065.

This is what the LEED reviewer is looking for. Statements and product data from manufacturers is no longer accepted by GBCI when documenting VOC compliance. 

This is a LEED Coach's response: "A wet-applied product (Adhesives and Sealants / Paints and Coatings categories) must have two documents provided: VOC content and VOC emissions evaluations (or General Emissions Evaluations, if you are looking at v4 instead of v4.1). The product data sheets that reference VOC content (distributed by the manufacturers) are accepted for VOC content documentation, but not for VOC emissions evaluations. For the VOC emissions evaluations, the third-party certificates or lab reports must be provided. If a third-party certificate is provided, and the certification body is not listed on the Third-Party Table, then the certification body must be accredited under ISO Guide 17065. If a lab report is provided, the laboratory that conducts the test must be accredited under ISO/IEC 17025. "

So in short - for VOC content, the manufacturer's product data is acceptable; for VOC emissions the lab report is required. 

If you have access to a project through LEED Online it has some useful graphics to help clarify what is within the weather barrier.  Under a LEEDv4 project go to the Low-emitting Materials credit click on the "Credit Library" tab, then click on the "Guide" tab and select "Further Explanation" on the left menu.  There is a section on "Definition of Building Interior and Exterior" with 6 Figures (4 wall sections with different claddings, and 2 roof sections.) It is not crystal clear where the weather barrier is in all those details but generally we interpret them to mean that the weather barrier is outside, and components from the inside surface of the weather barrier are inside.  LEED v4.1 would be the same but apparently since it is in pilot there are no guides for v4.1 shown.

Hi Chyanne, where can we find the guidance / info that states that "If your project is v4 and you're substituting v4.1 credits, your materials can utilize v4 testing standards (CDPH Standard Method v1.2-2010 rather than 2017)." It would be helpful to know that it still applies, and I'd like to make sure before I go ahead with v4.1. Thank you! 

EDIT. Found the LEED interpretation : https://www.usgbc.org/leedaddenda/10495

Regarding whether the weather barrier is "interior" or "exterior" - this below is from the v4 Reference Manual: "The building interior is defined as everything within the waterproofing membrane. The building exterior is defined as everything outside and inclusive of the primary and secondary weatherproofing system, such as waterproofing membranes and air- and water-resistive barrier materials."

Cold climate building are frequently equipped with a robust vapor barrier located on the  inboard side of framing and insulation, vapor permieable weather barrier and siding.  TYhis vapor barrier it typicly a 6-10mils polyetylene plastic and is sealed at all laps and edges, effectivly isolating those wall components ourboard of that layer  from the interior environment.  In htese design cases, is that what woudl be considered the waterproof membrane?  I am not seeing any depeer explantionin v4.