Stucco and air gap question with Home Slicker
I am remodeling my house down to the studs. Put In cellulose insulation and OSB – 2×4 walls. Going with stucco on bottom half. I read that this is a dangerous combo without an airgap. So I forked out the bucks and bought Home Slicker stone and stucco to create a 1/4 inch air gap. We have installed standard Tyvek and have the Home Slicker Stone and Stucco over it. So my big question is do we need another layer of felt on the outside of Home Slicker or is the layer of stucco blocking fabric that comes attached to Home Slicker good enough?
To be more explicit. Code requires two layers of felt due to the fact that stucco binds to the first layer leaving the second an intact weather barrier. Is this kind of protection needed with homeslicker stone and stucco product? Would adding a layer of felt on the outside of the homeslicker air gap create some kind of unintended consequences by having a WRB on both sides of my 1/4 inch air gap?
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http://www.benjaminobdyke.com/uploads/resources/Home_Slicker_Stone__Stucco_6__10mm_Installation_Instructions_090613.pdf
Joel,
I noticed that you have posted this question in two locations. When you posted it on the page with my stucco article (To Install Stucco Right, Include an Air Gap), I answered on that page. Here is what I wrote:
There are really three questions here:
1. What does the manufacturer of Home Slicker Stone and Stucco require?
2. What will your local building inspector require?
3. How much risk are you willing to accept?
For the answer to question 1, see this document: Home Slicker Stone and Stucco Installation Instructions. That document recommends that lath and stucco can be installed on top of the product in question, as long as there is a WRB between the wall sheathing and the Home Slicker. (See illustration below.)
For the answer to question 2, contact your local building department. Your inspector may want to see an additional layer of building paper or asphalt felt on the exterior side of the Home Slicker Stone and Stucco, because the wording of the building code gives your inspector that latitude.
The answer to question 3 is hard to pin down. However, after researching stucco failures, which are very common, I would include a layer of asphalt felt (or use paper-backed lath) on the exterior side of the Home Slicker product if I were building a home with stucco. Asphalt felt is cheap, and the insurance is worth it.
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Joel,
I'll add another point in response to your last question: "Would adding a layer of felt on the outside of the Home Slicker air gap create some kind of unintended consequences by having a WRB on both sides of my 1/4 inch air gap?"
The answer is no. Installing two layers of building paper or asphalt felt on the exterior side of the air gap won't have any negative consequences, even if you have a WRB on the interior side of the air gap.