The formation of hexagonal and lamellar surfactant-silicate mesophases at room temperature has been investigated by in situ synchrotron small angle X-ray scattering. Emphasis was given to the influence of butanol and hexanol on the surfactant-silicate phase behavior. The experimental setup included a continuous flow reactor allowing a resolution in time as high as 0.3 s. Depending on the reaction composition, one, two, or three coexisting phases were observed. The results are discussed in terms of time-dependent changes in the concentration of cosurfactant not incorporated into the composite aggregates. Although many of the observed effects are paralleled by well-known properties of aqueous surfactant solutions, important dissimilarities exist. Furthermore, the relative intensity of the high-order reflections are suggested to correspond to the degree of interaggregate condensation in the composite mesophase.