What is a ‘blow-out’?

A ‘blow-out’ is a break in the form, generally due to the pressure from the liquid concrete during the concrete placement and/ or consolidation. Fox Blocks ICFs are designed to maintain a high safety factor of pressure from the liquid concrete. Damaged forms or failure to support areas where forms have been cut leaving a large area of EPS between the web supports may cause a blow-out. Over consolidation may also cause a blow-out.

Fox Blocks recommends the Pre-Placement Checklist be reviewed for all wall assemblies prior to the placement of concrete, to find potential problem areas and install additional strapping or support to prevent blow-outs. Generally, for an Fox Blocks form, the size of a blow-out may be limited to the EPS between the webs, 6" or 8" wide by the height of one form. If a blow-out occurs, the concrete pour moves to another area on the wall, the hole is patched by replacing the EPS, installing wood support over the area, and then resuming the pour.