For many hyperbolic paraboloid shells, the horizonal reaction is provided by horizontal ties between the supports. It is shown that the horizontal movement of the supports associated with the elongation of these ties will alter sufficiently the stresses in the shell membrane and the axial forces and moments in the supporting edge members that these movements must be considered in the analysis. The effect of the outward support movement for gable‐type HP shells supported on four corners is to reduce the arching effect across the diagonal supports, resulting in behavior that resembles more closely that predicted by membrane theory. When such shells are placed to form continuous structures, the effect of the outward support movement causes the portion of shell in the vicinity of the first rows of interior supports to behave as inverted umbrella HP shells.