Abstract: A grid framework structure for supporting a load handling device operative to move one or more containers includes: plural upright columns arranged to form vertical storage locations for containers to be stacked and be guided by the upright columns in a vertical direction. The upright columns are interconnected at their top ends by a first set of grid members extending in a first direction and a second set of grid members extending in a second direction, the second set running transversely to the first set in a substantially horizontal plane to form a grid structure having grid cells. The first and second sets of grid members are sub-divided into plural grid elements such that adjacent grid elements extending in the first direction or the second direction are offset with respect to each other in the horizontal plane by at least one grid cell.