We need to choose the paint for the interior walls in our Passive House, and I believe we were advised to use latex paint to introduce vapor retardation. We are in Pittsburgh, PA, Zone 5, with a lot of plants in the house, and a thick wall: exterior cladding, 1×4 rainscreen, 4” of mineral wool, Solitex Mento weather barrier, plywood, 6 or 8” of cellulose, 5/8” of drywall. Electrical outlets were sealed with electrical putty… On average, using Joe Listburek’s rule of thumb calculation for dew point, we pass, although it is still T.B.D. as to what our interior conditions will be like w/r to temperature and humidity. I read some of the blogs here on the topic, and understand vapor retarder Type III like latex paint would be sufficient to meet the code.
Looking through the paint options (need to be low VOC too), I have hard time finding any information about permeability, or even locate “latex” paint. Some latex content may be there, but the paint is called “acrylic”…? The manufacturers don’t seem to provide much info. Should one include some vapor-retarding primer instead? What products might be suitable to meet both criteria?
For low VOC, we determined these would meet the requirement.
• Per NGBS indoor air quality requirements, architectural coatings need to be selected from the following list: Sherwin-Williams Emerald (CARB), Sherwin-Williams Harmony (CARB, 2g/l), BEHR Premium Plus (meets GS-11 at 46g/l, but is not certified), Miller acro pure (certified GS-11, 6g/l), Benjamin Moore Natura (meets GS-11 at <5g/l, but not certified). Thanks, Lucy
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