A system for sealing a space defined between a modular wall and a permanent structure includes a sealing material connected to the permanent structure and the modular wall and spanning the space defined therebetween. The sealing material is configured to transform from an expanded state to a recovered state in response to a stimulus to form a seal. The stimulus can be, for example, heat, whereby heating the sealing material at or above the transition temperature for the sealing material causes the sealing material to transition from the expanded state to the recovered state.