Can the plastic webs be detected by using stud finders?
A stud finder typically uses the density of materials to locate studs. The polypropylene (plastic) web material will show up on high quality density stud finders. Note, the webs in Fox Blocks are spaced at 8″ (200 mm) on center and will be continuous vertically on each side of the wall.
How does the ICF block get secured to the foundation?
The ICF blocks are held in place with either low expansion spray foam or a metal starter track. The bracing/alignment system, typically installed after the 4th course of block, also supports the ICFs in place. Once the concrete is in the wall there is no concern with the forms moving. The concrete is connected to the footing with reinforcing dowels.

How Much Does an ICF House Cost to Build?