Vapor redardant paint

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Author Message David Axt, AIA, CCS, CSI Senior Member Username: david_axt Post Number: 730 Registered: 03-2002 Posted on Thursday, October 05, 2006 - 02:44 pm:    Our building envelope consultant (don't get me started) wants us to remove the vapor retarder we have specified and specify vapor retardant paint. The project is in the NW and we typically specify CertainTeed Membrane or Lamtec VMP-VR vapor retarders that go between the studs and gypsum board. Personally I think that vapor retardant paint 1980's idea. I never see it used anymore nor would I know what type of paint to specify. What is your opinion of vapor retardant paint? Does it even work? Harold S. Woolard Senior Member Username: harold_woolard Post Number: 33 Registered: 12-2003 Posted on Thursday, October 05, 2006 - 02:58 pm:    Just ask for a guarantee from the Paint manufacturer for 10 years for any moisture intrusion into the structure and you will end up with what you specified the first time. Wayne Yancey Senior Member Username: wyancey Post Number: 186 Registered: 05-2005 Posted on Thursday, October 05, 2006 - 04:21 pm:    David, It is not a vapor retarder paint but vapor retarder primer. Sherwin Williams has such a product. I will e-mail you the product data sheet or simply call Eddie Stein. PNW does not require a Class I vapor retarder [0.1 perms or less] but a Class III vapor retarder [10 perms or less and greater than 1.0 perms] will suffice. Plywood, OSB, most latex-based paints are Class III and are considered vapor semi-permeable. Use unfaced batts. That said, I cannot understand not using Membrain and unfaced batts. Paper face batts will also work in the PNW. Avoid vapor semi-impermeable vinyl wall covering on the interior surface of exterior walls. No mention in your post of air barrier or will that also get you started? Wayne Phil Kabza Senior Member Username: phil_kabza Post Number: 213 Registered: 12-2002 Posted on Saturday, October 07, 2006 - 05:57 pm:    The vapor retarder primer should help hold moisture within the gypsum board that would otherwise be controlled by the building HVAC system. Probably not one of your performance requirements. There are some places where the vapor retarder paint is useful, such as some retrofit applications, or when the contractor knew better than the architect and left the vapor retarder sheet out. Without perimeter and penetration treatment, the vapor retarder paint is just academic, though. Do you have a current liability insurance certificate from the building envelope consultant? David Axt, AIA, CCS, CSI Senior Member Username: david_axt Post Number: 731 Registered: 03-2002 Posted on Monday, October 09, 2006 - 01:13 pm:    Phil, "Current liability certificate"? Please explain. BTW, the Owner hired the envelope consultant, not the Architect. Thanks. Anonymous   Posted on Monday, October 09, 2006 - 05:26 pm:    David, We have a developer client that informed us recently that a group of attorneys is using vapor retarder primer applied to gypsum board as a way to bring defect claims against designers and builders - for condominium projects. They are confident that in nearly ALL cases, the paint will not have been applied correctly, supported by tests they have commissioned from cut outs in the painted gypsum board demonstrating a perm rating of less than what the code requires (1.0 perm or less in the PNW, last time I checked the code!!!). Stick with MemBrain! Wayne, while building science supports the use of a vapor (diffusion) retarder in the PNW between 1-10 perms, I am not aware of any code change that allows this, yet. Please elaborate... (Unregistered Guest) Unregistered guest Posted on Monday, October 09, 2006 - 05:37 pm:    Can you share the initials of the consulting firm that made this recommendation?? I'd be interested in knowing... Much appreciated. Anonymous   Posted on Tuesday, October 10, 2006 - 08:38 am:    Why do I have a sneaky feeling that most of the so called "Building Envelope Consultants" are owned by law firms? David Axt, AIA, CCS, CSI Senior Member Username: david_axt Post Number: 734 Registered: 03-2002 Posted on Tuesday, October 10, 2006 - 01:50 pm:    The building envelope consultant that recommended using vapor retardent primer instead of a vapor retardent membrane is (BET&R) Building Envelope Technology and Research out of Seattle Washington. My firm has reviewed their report and has a lot of issues with what they recommend. Much of is belt and suspenders with another belt. Some of it just does not apply to our specific application. Phil Kabza Senior Member Username: phil_kabza Post Number: 214 Registered: 12-2002 Posted on Tuesday, October 10, 2006 - 09:04 pm:    Sorry, David - I was being a little snarky about the insurance certificate. But it seems some owners want to listen to every consultant except the design professional who is the only one responsible for the design - and architects roll over and die when these consultants show up on a project. When was the last time a "building envelope consultant" was held liable for the failure of a design? There are some brilliant people in that field, but also a lot of engineers looking for high fee, low liability gigs. I've written voluminous responses on boilerplate reports that demonstrate consultants' limited ability to read and interpret specifications. David Axt, AIA, CCS, CSI Senior Member Username: david_axt Post Number: 736 Registered: 03-2002 Posted on Wednesday, October 11, 2006 - 01:44 pm:    Boiler plate reports.....you got that right mister! We have sent kind of a scathing report back to the owner defending the decisions that we (the architect) has made and discounting the decisions that the consultant has made. This brings up the big question of liability. If we don't follow the consultant's recommendations there is a problem are we liable? If we do follow the consultant's recommendations, even though we disagree, and there is a problem are they liable? Richard Howard, AIA CSI CCS Senior Member Username: rick_howard Post Number: 97 Registered: 07-2003 Posted on Wednesday, October 11, 2006 - 02:07 pm:    The design professional will be the one they come after if there is a problem, whether or not there was a consultant and whether or not his report was followed. It's the "pot of gold", his E&O insurance, that makes him a big target. I'd bet the consultant's agreement limits his liability to the amount of his fee. The only mitigating factor would be if the owner directed the design professional to follow the consultant's recommendations and the consultant continued to demonstrate responsibility through construction to final acceptance.