Please advise on window and flashing detail for an "outy" window install on ICF.

If using synthetic bucks (our current plan, unless you adivse otherwise), is it correct that the flanged window is attached to the face of the buck that is (roughly speaking) flush with the outside of the ICF wall?
If so, please describe the best method of flashing the window (2 layers class D, or ?).  Since we plan to use acryllic stucco (unless this forum suggests something else), i am concerned that if we simply seal the window in place, and use flashing tape that this may not be right since any water getting behind the stucco will inevitably get behind the tape and into the window.

Also, please advise if this forum has particularly good or bad experiences with acrylic stucco vs cementatious stucco vs products like stucco-crete. my intent is a maintenance free surface.

many thanks for your help, Steve

Steve - this is one of the weakness of outies. There are a number of ways to deal with this issue. Normally you would only have to worry about the tops as moisture will "usually" drain straight down. If your windows are close to your soffit than you don't have much of an issue as it would be close to impossible for the water to get in above the window.
If you are using conventional nailing flanged windows, you have a number of options.
1) just silicone /foam/duct seal the top and side flanges to the ICF.
2) cut a flashing in on an angle above the top of the window such that the 45º piece goes through the ICF to the concrete, than comes down the face of the wall and over the flange, turns 90º out from the wall and then a small 45º drip edge.
3) route a grove in above the flange and bury the top edge of the flashing tape in the groove, fill the groove with stucco base and than apply standard finish coat over it.
There are many other ways of doing this some are good some not so much.

If you are doing some type of batten around the windows than you have more options.

Acrylic stucco is an almost prefect match for ICF, however it is limited by the applicator. Almost every problem with acrylic stucco is tracked back to improper installation. As you infer above, the one issue is that the actual drain plane should moisture make it through the stucco is the concrete foam interface. It is difficult to make an actual self draining plane for the moisture to follow and come out the bottom. It is important that the layers of stucco are applied correctly and at the correct thickness.

I think what most synthetic stucco companies want is a joint between the window that can take backer-rod and caulking. This joint is to be flexible to handle differences in expansion and contraction. So with a nailer flange window or door that protrudes a trim band should be installed. Trim bands can be a nice accent. Check out the details. http://www.totalwall.com/PDF/Details/TotalDirectICF_DetailsLong.pdf

However I do not want a trim band on my own house, I am going to skip the trim band and just caulk the junction of stucco to window. I have just had the basecoat on for two years, no trim band, caulk or finish. But I do not recommend this.

There are some really good window flashing details on Green Building Advisor forum. Some are free but others you have to be a paying member.

Prosoco R Guard is a really good sealing material to use. It is a urethane waterpoof barrier. Check out their website.

Most on GBA recommend a recessed window install but a flush mounted is fine.

http://www.senergy.basf.com/SiteCollectionDocuments/Details%20PDF/Senergy_Details_Surfacing_Systems_for_%20ICFs.pdf

All the Senergy details with nailer flange protruding windows show a trim band.

The Prosco R Guard appears to be all liquid applied.

What we need is a thin peel and stick flashing that synthetic stucco can be applied over.

Posted By EnergyWiseBuilding on 13 Apr 2013 10:45 AM

What we need is a thin peel and stick flashing that synthetic stucco can be applied over.

Not sure if this would work or not, but my framing crew installed BITEC Defend Ice & Water protection over my low slope porch roof and in the roof valleys.  Rather than a smooth top surface, this stuff has what appears to be sand impregnated in the top surface to give it some grip for the roofers.

http://www.bi-tec.com/index2.html