Step 19: Consolidate the Concrete

When pouring concrete, air can become trapped inside the concrete mix. If these air pockets aren’t removed they create voids that reduce the strength of the wall. Vibrating the concrete inside the wall temporarily returns it to a semi-liquid state, removing air voids and guaranteeing a strong, solid wall.

Internal vibration is required for any ICF structure. External vibration is not sufficient and is not code compliant. Use a low impact pencil vibrator with a ¾ to 1-inch head and a 1.5 HP motor. Either gas or electric is acceptable. The recommended technique is fast in/slow out with an average pull out rate of 4 to 6 inches per second.