Is there a problem when placing concrete, dropping concrete from the top of the wall which may be over 8' (2.4 m)?
No. Specifications in the America Concrete Institute (ACI) do not limit the maximum distance concrete can free fall. Engineering studies and reports have shown that free fall from up to 35' doesn’t reduce concrete quality and there is no evidence of segregation or weakened concrete strength. ICF concrete design calls for a high slump mix which assists in reducing segregation.