Issue with Box Collider at Height

I have created a pile of boxes in my game to crall under. My character collides with the boxes on the ground but any above that it just walks straight through. The parameters of the corridoor are 200 units tall and wide and the box consumes the top 100 units of the corridoor and 100 units each direction. The character controller is also set at Y:100 for position and scale and the graphics for it are alligned to that. The "Is Trigger" is unticked for all colliders.