The invention provides a method and assembly for fastening and reinforcing a structural member (e.g., an automotive vehicle pillar, such as an automotive "B" pillar). The assembly preferably includes a structural member having a first and a second portion defining a cavity therebetween. An expandable reinforcement material, such as an epoxy-based reinforcement material, and a spacer are typically disposed within the cavity. The assembly also typically includes a fastener or fastening assembly. In operation, the spacer preferably assists in supporting the first and second portions of the structural member during changes of state (e.g., softening) of the reinforcement material.