A grain storage bin includes a cylindrical wall formed by a plurality of panels arranged in rows with a bottom edge of a first row bolted to a top edge of a second lower row. At each joint the bottom edge of the first upper row is overlapped with and outside of the outer surface of top edge of the second lower row and the bottom edge is fastened to the top edge by bolts carrying spacers as to define a first channel along the joint for passage of air. A cover strip overlies the channel and extends from an upper edge of the strip at the inner surface of the first panel above the channel to a lower edge of the strip which is fastened to the top edge so as to define a second channel so that air can pass between the interior and the exterior through the first and second channels while the particulate material is prevented from escaping through the first channel by the cover strip.
