A roof for a large diameter grain bin is formed by roof rafters inclined from a top of the wall to a top ring, with sheet metal panels in an upper row extending from the ring to a circular bottom edge and a lower row extending from a circular top edge to the wall. A circular bracket of Z-shaped cross section is carried on the rafters by upstanding support legs and provides an upper flange engaging the bottom edge of the upper row and a lower flange engaging the top edge of the lower row and an interconnecting web portion. One or both rows are supported at a mid point on a cylindrical tube bent to form a circle butting the panels and supported from the rafters on leg members which include a center strap which can be bent around the tube and two legs bolted to the rafters.