One more question about rainscreens
When using a 3D rainscreen material like House Slicker, Delta-Dry Stucco & Stone, or Sure Cavity behind stucco, you need something between the stucco and the rainscreen material to keep the stucco from clogging the channels for drainage and air. Some of these materials come with a pre-bonded fabric to do this, whereas you would otherwise put something like a layer of felt on top of the rainscreen and behind the lath and stucco.
I had thought that the structure that went (from inside to out) sheathing, WRB, rainscreen air gap, WRB stucco would be better because, while the stucco might dry more slowly, the outer WRB would minimize the amount of water making it into the rainscreen gap and thus reduce the amount of vapor in the space and the risk of liquid water finding a path through the inner WRB to the sheathing. My contractor says hell, no. He says that will defeat the purpose of providing a drainage plane. I’m not sure that I see that. The point of the drainage plane is to keep the sheathing and framing dry, not to keep the stucco dry.
I have seen that people have built houses with felt outside of the rainscreen, but maybe that was just to serve as a stucco barrier because they didn’t have a rainscreen material that came with its own stucco barrier. Also, the makers of most of these products sell versions with a non-WRBs stucco barrier on the outside, but I haven’t seen one bundled with a WRB intended for the outside.
So, I think my contractor is probably right, but would like to hear what people here think because I’m sure I got the idea of a WRB on each side of the rainscreen from somewhere and I want to know if anyone thinks it’s best.
Thanks in advance.
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