We present a logic of separating modalities, LSM, that is based on Boolean BI. LSM's modalities, which generalize those of S4, combine, within a quite general relational semantics, BI's resource semantics with modal accessibility. We provide a range of examples illustrating their use for modelling. We give a proof system based on a labelled tableaux calculus with countermodel extraction, establishing its soundness and completeness with respect to the semantics.