What thickness of vapor barrier paint do you need to apply instead of a poly vapor barrier?
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The thickness of vapor retarding latex paint - Is measurement wet or dry?
Kim Boas
July 24, 2020Last updated: Sept. 25, 2020
I am applying a vapor retardent latex primer to my concrete basement floor and would like to know if one coat is thick enough. The thickness cited in an ecohome article was 0.00031. The technical data for the paint has a wet thickness that matches the article but a much smaller dry thickness.
When we used avapor retarder primer(vapor barrier paint) in ourEdelweiss LEED Platinum Demo Houseinstead of a 6 mil poly vapor barrier, it was for the walls not the floor. As for thickness, that is what we would call a bit of a concern with using it as a vapor barrier, it is harder to be sure there is consistency of coverage. Ours didn’t need a lot of moisture protection on the walls due to it’s construction, you can see more about the wall we build with vapor barrier paint here –
Building science of walls in cold climates– video
So I’m wondering, what are you using it for on the floor? I ask for a couple of reasons – if you aren’t putting anything else on top of it, would it not be subject to wear? If So I’d be using several coats probably. If you plan to put flooring on top of it, would you not be better with a standard 6 mil (or more) polyethylene vapor barrier? Vapor barrier paint is a great option when you want vapor protection, but also some ability of walls to dry to the interior during certain conditions. I can’t think of any condition when you would want moisture to escape from the floor, so I must be missing something…
I'll be putting latex floor paint over the vapor barrier primer. Since the house I recently moved into has an open stairwell to the basement, there is a musty / mildew smell. I've foamed and put 6 mil poly in the open crawlspace connected to the basement and painted the bare concrete walls with drylok. The floor was painted with latex, so I couldn't use the drylok floor paint. The latex vapor barrier paint seemed like a reasonable option.
我不愿意去权衡太多的赞成或反对，我只是不确定它会有多好，因为它真的不是预期的目的。并不是说它不起作用，但如果地板真的很潮湿，我想知道它的油漆能保持得多好，或者它最终会不会裂开或发生什么事。作为一个起点，这不是一个坏主意，因为这是一种非常廉价的解决问题的方法，但你可能会从制造商那里得到更好的见解。你也可以去油漆店或地板整理店看看他们是否也有想法。最坏的情况是它不起作用，然后你可能不得不做一个真正的多聚蒸汽屏障和某种浮动地板。这房子建了多久了?我只是想知道混凝土下面是否会有一个蒸汽屏障，如果它是相当新的，如果它是相当老的，没有，所以它会更潮湿，这可能会影响它的工作效果。
I assume you've already gone the dehumidifier route? That's the first step to instantly lowering basement humidity, just mentioning it in case you don't have one.