A concrete form unit includes opposing sidewalls which are preferably made of foamed plastic or other insulating material. Articulated spacers extend between and connect the sidewalls, and are capable of folding about themselves both at an elbow situated between the sidewalls, and also at their junctures with the sidewalls. The folding ability of the spacers allow the sidewalls to convert between a collapsed state wherein the sidewalls are in close adjacent relationship and the spacer links are oriented at least substantially parallel to each other and at least substantially parallel to the sidewalls, and an expanded state wherein the sidewalls are in distant spaced relationship with the spacer links being oriented at least substantially parallel to each other and at least substantially perpendicular to the sidewalls. The collapsed form unit therefore assumes an overall box-like shape, and therefore the collapsed form units are easily stored and shipped with minimal lost storage volume.