Support means for foldable structures of the type having a roof of foldable material and a vertical mounting shaft staking perpendicularly to the ground. The interlocking support means consists of upper and lower interlocking members. A plurality of horizontal ribs are pivoted and clamped in the interlocking support means so that the ribs are held horizontally, but can fold down along the vertical shaft for transportation. The ribs have a channel cross-section. A rope extends from the end of one rib through the rib channel, through the interlocking mounting means and then through a second rib, whereby the ends of the rope may be used to stake down the structure and support side walls.