When parging to an ICF wall, these are the steps we take to prepare the wall before mud gets spread. We take in account the wall as a whole assembly and make sure that we have water protection from top to bottom. Some of these considerations can be used for stucco and/or stone applications to ICF. The take away...creating a drainage plain to allow water to exit after parging, stucco or stone gets saturated from heavy rainfall. This info seems trivial but you wouldn't believe how many people skip this thought process, even many "so called" professionals.