A frame assembly for supporting an extendable wall member of a portable shelter on a foundation. The frame assembly includes a plurality of frame members that are operably secured together. The frame members are positionable between a first configuration, in which the wall member is extended, and a second configuration, in which the wall member is retracted. At least one frame member includes an end that is disposed adjacent the foundation. Furthermore, the frame assembly includes a foot member with a support portion. The foot member is pivotably coupled to the end of the frame member to pivot between a first position, in which the support portion is disposed between the end and the foundation to support the frame member on the foundation, and a second position, in which the support portion is disposed away from an area between the end and the foundation.