ICF basement walls below grade membrane waterproofing over the exterior EPS foam are more prone to water intrusion than standard poured concrete with standard waterproofing adhered directly to the concrete. Easier to breach waterproofing membrane over foam than directly applied to concrete. Shrinkage cracks can be seen and injected on traditional poured concrete walls but not so with ICF. If the builder or waterproofing subcontractor won't give you a 10-15 year watertightness warranty, then don't use them.

If you have a leak, finding the source often takes much excavation and rewaterproofing larger areas because traditional poured concrete walls normally have localized water entry point. ICF can allow water behind the EPS foam board to bare concrete and water can be held and spread along the backside of the permanent Insulated form.

Voids are more frequent at windows and doors in ICF. Bracing during pouring is even more important than traditional poured concrete walls.

If you go ICF, choose the right builder and subs. Mission critical.