Abstract: The invention provides a fire-stopping product, an insulated building façade comprising a fire-stopping product, and a method of making a fire-stopping product. The fire-stopping product comprises a resilient, porous material at least partially impregnated with an intumescent agent and held in compression by a releasable restraint. When exposed to hot gases from a fire, the restraint yields to release the resilient, porous material in an initial expansion, thereby exposing the intumescent agent to the hot gases and allowing rapid intumescence to occur. When implemented in a ventilated building façade, the fire-stopping product is able to close an air gap in a short amount of time.