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Community and Q&A

Flashing below grade veneer

Josh_Man | Posted in General Questions on

Hey everyone, I really could use some help / advice.

I am in the middle of building my home, and my exterior cladding is veneered natural limestone out of Montana. It says 1.5 inch thick but some of it I believe is 2inch.

My architect works on very renowned homes in my area work and I feel if there was any integrity issues of his techniques word would spread and that’s not the case. They started as GC’s and found a niche in timber frames and now primarily design homes, but have tons of field experience and continue to do some timber installation.

So to my question, he has told me they often run the stone right down into the grade 6 – 8 inches down with no issues. He also sent me a finish details with the stone held up slightly above grade, probably for my peace of mind. I know lots of folks discourage this and actually want 6 inches above grade, but I think it looks goofy and I would have a gap of foam that I would need to cover.

I have ground contact treated plywood grade on the lower skirt of the house, and the newest I bought was actually below grade treated plywood.

I am planning cover the treated plywood with peel and stick 40 m membrane that will wrap onto the foam so the lower edge of the plywood is sealed, followed by commercial grade d Tyvek, 2 layers of grade D paper, and then a rain screen and will have a weep screed as well.

Am I setting myself up for future failure or will this be fine?

I have attached my finish details for all of your advice!


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  1. Expert Member


    I don't see a problem. As long as the top of the slab is 6" above grade, and the veneer stone itself is not affected by being buried, then I don't see an issue.

    1. Josh_Man | | #2

      Malcom, thanks for the response!

      The slab runs 6 inches above grade covered by 2inch ridged foam, but the treated plywood on the face of the foam will extend 6 inches below grade or at grade. The slab is 18 inches thick.

      I guess my original concern was water wicking up the treated plywood and rotting it out if the 40m poly were to break down below grade or something of that nature.

      Its 18 inches of treated plywood, then transitions to OSB above that.

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