A reinforced structural member is provided which includes a reinforcing member received in the cavity of a structural member. The reinforcing member includes a carrier having divergent, intersecting legs which preferably engage and rest upon the structural member, a thermally expandable reinforcing material, and a fastener for coupling the reinforcing material to the carrier. The thermally expandable reinforcing material is preferably provided as separate elements positioned on the carrier, whereby upon activation by heat, the expandable material melts, foams and expands so that after curing, the structural member is bonded to the carrier. The shape of the carrier in combination with the expanded reinforcing material serves to stiffen and reinforce the structural member. The thermally expandable material is preferably initially dry and non-tacky, and the fasteners serves to maintain the relative position of the reinforcing material elements on the carrier prior to activation of the reinforcing material.