The presence of gypsum during application of cementitious grouts inside masonry is a major concern, which may lead to the creation of ettringite and the subsequent damage of the masonry. The design concept of the presented hydraulic grouts is based on the reduction of the portland cement content to the 30%-wt of the total binder mass, in favor of appropriately proportioned mixtures of hydrated lime and natural and artificial pozzolans. The behavior of the system lime-pozzolan-portland cement in the presence of gypsum is investigated. A series of mortar specimens were fabricated, in which a part of the sand was replaced by gypsum. The grouts were used as binders, and the evolution of the length change and the modulus of elasticity were followed for 730 days. A large expansion was recorded in the lime-natural pozzolan-portlant cement mortars, which may be considered as non-sulfate resistant. Conversely, substitution of a part of the natural pozzolan (10%-wt of the pozzolan) by an equal in weight of silica fume lead to a reduction of the recorded expansions.