Abstract: The invention is an adjustable building frame comprising a plurality of interfitting parts. The frame includes a base having a pair of opposing receiving surfaces and several parallel roof members received and connected by and between the receiving surfaces. The roof members are generally perpendicularly to the opposing receiving surfaces of the base. Each roof member comprises at least two telescoping sections which may be telescoped together or apart to adjust the length of the roof member. Increasing the length of each roof member of the frame increases the height and volumetric area defined by the frame, and decreasing the length of the roof members decreases the height and volumetric area defined by the frame. A flexible cover is attachable to the roof members by a plurality of clasps or a flexible but more rigid cover is attachable to the roof members by a series of bolts. The cover ideally overlaps itself, so that it will expand or retract as the height of the frame is adjusted.