We wish to build with a veneer stone wainscot detail, using one of the real stone products, not the cast manufactured type such as Cultured Stone. Thickness of this sawn stone veneer is 2", and we want to have its bottom at or just below finished grade. Anybody done this? Tales or success or failure? Photos? The pic is from one of the websites of manufacturers of this type cladding.

Is this helpful:

http://volcanicstone.com/wp-content/uploads/2009/12/Stone-Veneer-on-Insulated-Concrete-Form.jpg

I plan on doing something similar with a real stone wainscot. Please post if you have any additional examples/details.

I am doing this over ICF with a thin ledgestone veneer. It runs about 1" - 1-1/2" thick. A couple issues came up with the masons who looked at the job.

1. Drain plane
2. Attachment
3. Weight.

The first we solved with a product that is like thin polymer brillo pads stuck to a tough backing. This goes right against the ICF (backing or smooth side out) and provides a bit of a drain plane back there. The backing keeps the mortar scratchcoat and setting bed from occluding the drain plane.

The attachment issue was fairly easy as the masons were more comfortable seeing expanded metal lath, so we just added that over the drain plane product. You need to have adequate attachment to the ICF webs using some kind of corrosion-resistant screw which holds on both the expanded metal and the drain plane product. It will hold a lot of the weight of the mortar and stone.

The third item, weight, might be a bit more problematic for you. Ail the masons wanted to see a brick ledge to start on and to support the weight....BUT, when they saw how thin the veneer was, they all agreed that could be done without a brick ledge. In talking with them, they all said that if the product was any thicker, they would need something else there to start on. At 2", you might be treading in that territory.

That brings us to the final item which plays a part. If you have your veneer starting below grade, you have both the problem of where the moisture that gets behind can drain to and the possibility of continuously drawing up moisture from the ground through wicking. If you could guarantee a good coarse pad of gravel up against the ICF wall, you might escape that problem, but that would be hard to maintain over time. When they wanted the brickledge, my solution was going to be placing a line of the thin 4" X 8" X 16" cinder block against the base and bedding it well in the gravel. I figured it might be porous enough to get some drying action going there and provide some starting support for the masonry.

I ultimately, I ended up with sidewalks or other concrete surface under about 80% of the stone veneer, and just had the concrete guys pour some little 12" ledges under the rest of it for the masons to start on.

good discussion..i'm not an icf guy, but my first inclination would be to pour a footing/brickledge outside the icf plane....... a 2" stone veneer will match or exceed the weight of a brick veneer

From my own experience, cured mortar sticks to styrofoam so well that it is impossible to remove without breaking the styrofoam.
Therefore I don't understand why one would use a metal lath? I thought the purpose of a metal lath was to serve as a structural attachment, for example on wood stud walls. What's the purpose of the metal lath on a styrofoam substrate?
Also, why would you need a scratch coat under a setting bed? I would just install the stone veneer with a high quality mortar mix directly on the styrofoam.

Posted By galore on 05 Oct 2012 10:16 PM
From my own experience, cured mortar sticks to styrofoam so well that it is impossible to remove without breaking the styrofoam.
Therefore I don't understand why one would use a metal lath? I thought the purpose of a metal lath was to serve as a structural attachment, for example on wood stud walls. What's the purpose of the metal lath on a styrofoam substrate?
Also, why would you need a scratch coat under a setting bed? I would just install the stone veneer with a high quality mortar mix directly on the styrofoam.

According to this article a metal lath is NOT needed on EPS/ICF. The article agrees with what you said, install the stone veneer directly onto the ICF with a good quality mortar mix, no scratch coat under a setting bed.

JLC Article

It makes sense since the EPS is held together by the webs and the concrete. In other words, the exterior EPS isn't going anywhere.

Therefore I don't understand why one would use a metal lath?

One reason might be that old habits die hard. In some places, it is difficult to find a mason who has experience with styrofoam and would be willing to do without what he is accustomed to seeing. Another reason might be that expanded metal lath could still be indicated for structural reasons.

I thought the purpose of a metal lath was to serve as a structural attachment, for example on wood stud walls.

That is correct. When used with ICF, the structural attachment would be to the ICF web. Please note that this is a true structural attachment and fastener type, depth of penetration and quantity used will all be important factors, depending on the weight of the masonry.

According to this article a metal lath is NOT needed on EPS/ICF.

The article you present deals with manufactured stone. That is a substantially different product, both in terms of weight and adhesion. This thread started with natural stone, which is a heavier product and may require different treatment, particularly in terms of "structural" attachment. I believe that the key may be found in established building codes, which specify attachment requirements based on the weight per square foot of the installed "stone" facing.

my house and shop have 1.5" SM foam.. not icf but some what the same to the stucco application. we use lath (tight diamond expanded metal) on the corners and around the windows. then we go over it with stucco wire (bigger grid welded wire)