The present contribution specifically considers the tensile stress exerted by in-pore (or confined) capillary liquids and the role it possibly plays on the host solid mechanics, in absence of significant confining pressure. This situation stands for any unsaturated porous systems submitted to drying-wetting cycles. An original combination of micro-thermometric procedures applied to liquids occluded inside quartz closed cavity, with Raman scattering data collected in the solid quartz lattice, leads to conclude that not only tensile guest liquid can act on its host solid, but can result in solid cracking in subcritical conditions. These processes are of importance for natural or man-made materials present in the Earth’s environment, where water and other active species are present, for which various combination of pore fluid and confining pressure/tension are possible, and displacements and stresses are small.