An insulated concrete form system having a pair of bottom U-shaped channels secured to a concrete slab that serve as a footprint for a concrete wall. Exterior and interior foam sheets are aligned within the bottom U-shaped channels that define the wall. Top U-shaped channels are slipped over a top edge of the foam sheets. A plurality of strongbacks are used to provide structural support for the foam sheets during a concrete pour of the wall. The strongbacks each have a pair of hangers adapted to be secured over the top U-shaped channels to secure the strongbacks to the foam sheets. A top wall spacer is used to join a strongback on one side of the wall cavity to a strongback on a second side of the cavity to resist pressure exerted outward on the foam sheets during a concrete pour to form the wall.