The recommendation is that you just apply it on. Most ICF's are 2 lb/cuft density. You cant go wrong with that - same as EIFS.
In case of a natural dister or accident (if you late your wife drive) its really easy to fix.

Plenty of stuccos around....

Consider the following - Sto, Parex, Permacrete, Oro Coatings,
Drywit sucks... just a personal opinion...

Do a wire lath then put a conventional mud coat on it. Then choose either a conventional or synthetic finish on.

It sounds to me that if the contractor is worried about damage to the walls later on then that would be the best way.

  

What they said.

ICFs are great for stucco.

Are you talking about cement stucco or the synthetic (acrylic) stucco?  I know that synthetic stucco (e.g., Dryvit) is typically installed over 1-1/2" of EPS (bead board) that is lower density than the typical ICF foam.  It leaves the wall with a hollow sound when you tap on it.  My first reaction was that the finish was fragile and would suffer damage over time, but I have accidentally bumped it on occasion with building materials with no noticeable damage.  I followed Dryvit's recommendation to apply two layers of mesh on grade-level walls for added strength.  From my limited experience, Dryvit is a good product.  What's more important is your choice of an installer.

we have been building/distributing with icf in s/e florida since 1995 (keys to cape kennedy). about 70% our projects were finishid with stucco, the rest with fiber cement siding.
many builders have used regular stucco applied with or without metal lath applied, then paint. cracks are normal and the paint becomes the line of water defense. some used synthetic stucco basecoats with fiber glass or synthetic mesh, then regular mud for texture and paint. some used all synthetic stucco systems (sto, dryvit, parex, synergy etc) directly on the icf forms. key for all systems is the forms must be cleaned or rasped before application.
attached a few pictures of a 35 year old icf condo directly on daytona beach, stucco is metal lath and grey mud, then painted. owners say no problem ever in all this time, just normal cleaning and painting maintenance ie, pressure washing, cracks caulked, then painted. notice the recessed and caulked windo returns/sills.
personally, in colder climates i would use all synthetic (eifs)stucco, due to more expansion/shrinkage during summer and winter seasons. flashing/caulking of openings and maintaining that seal is very important with all systems.

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insuldeckflorida, what about regular cementitious stucco in the first coat and then synthetic as the last coat before paint? (the only combination you didn't mention, but it's what I've been reading about...)

you may need to be concerned with having a smooth surface to rub out the eifs granulated texture/finish...
check warranty of eifs finish with that combo.....
and color fastness....
and you can always paint it if needed later on....

on my own house (50% 40 year old cmu added on with icf, 50% new icf) i used regular stucco with icf base coat, then what we call a knocked down skip-trowel finish, similar to adobe/old world "lumpy" stucco...then paint...some hair line cracks, but the paint covers those...

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There currently is no ASTM spec for conventional Portland stucco direct applied over ICF's. Florida Building Code requires wire lath for applications of dissimilar products relative to stucco. The PCA also recommends a paper back wire lath for this application. This is an area where ICF's add cost since stucco can be applied directly over CMU. Yes, synthetic stucco can be direct applied with F/G mesh but again, more expensive than traditional Portland Stucco

Permacrete prides themselves in being the ICF stucco people. I think mostl of their testing has been over ICF's. The impact on Permacrete is over 6000 psi. They shot it with a .45 at 18 inches with only minor dimples. Great stuff!

dwangle,

You know I am a little intrigued with the shot being fired with a .45 at 18 inches. I'm pretty sure that if it were shot at an ICF wall, it would do more than give it a tiny dimple. I worked on a project and threw a lacrosse ball at the ICF (stucco) as hard as I could and got a small dimple. I do think that the esp will allow for dimples if hit directly with something very hard, though those occurrances are rare.

If permacrete has a youtube video proving the gun shot, then I will be extremely impressed!

renangle

Yes, this is exactly what our builder is worried about.
He is suggesting a tilt-wall system instead now, which he said would eliminate the concern and the wall would still be R-20 (vs. R-22 for ICF). Any comments on that? 

below is a tilt wall panel, finished with a textured roller on the ground as part of the concrete pour, no stucco needed.....
any texture/veneer is possible...
we can do this with insuldeck/tiltdeck, panels up to 60' tall, as large as you can lift them with a crane...

R value can be from 19 to 33 depending on panel thickness...

anyone interested in more info send me an email
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If you concern is something similar to a lacrosse ball (or golf ball) making a direct hit on your house, I honestly think that the chances are remote (unless you are on a golf course). You can do stone or something similar near grade and convert over to stucco as you go up. I would try to think of something else than steer away from ICF, but I'm sure that I'm biased. We elected to just use less stucco and more brick...but we are also working on a school where lacrosse is a big sport. Just my opinion...but the benefits of the ICF outweighted the stucco finish.

Here is a little test Permacrete did. http://www.permacrete.com/_pdf/permacrete_impact_test.pdf

Renangle-you are right about the .45 not being shot at an ICF wall. I just read in their literature that it was on 1/8" aluminum panel backing. It has the actual pictures of the bullets - quite impressive.

Re:Insuldeck
Textured/stamped concrete walls with no siding or stucco make sense to me. How do you seal the gap between each panel?

joints are sealed by inserting a foam backer rod and then filling the gap with pu or silicone caulk.
this is the way every tilt-up structure is sealed.
takes care of expansion/contraction and water.
you can research it here:
http://www.tilt-up.org/

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