A microstructure, consisting of conventional rods, is herein shown to exhibit “negative hygroscopic expansion” (NHE) in the form of a reinforced double arrowhead with freely rotating joints, whereby the NHE occurs in the direction perpendicular to the reinforcing rods. A kinematic analysis enabled the condition of NHE, as well as the conditions of its “negative thermal expansion” (NTE) analogy, to be established. Results show that the likelihood of “negative expansion” is increased when the longer inclined rod expands to a much greater extent in contrast to the expansions of the reinforcing and the shorter inclined rods. Combined description of NHE and NTE not only allows the conditions of “negative hygrothermal expansion” (NHTE) to be put forth but also the condition by which “zero hygrothermal expansion” (ZHTE) is achieved by means of mutual cancellation between both types of expansions. This concept of ZHTE allows a more flexible design of materials and structures that are exposed to simultaneous changes in moisture concentration and temperature, as it does not require the minimization of both the coefficients of hygroscopic and thermal expansions.