A method of manufacturing a loading unit for use with a surgical stapling apparatus, wherein a surgical buttress (B1, B2) is pre-loaded onto the loading unit during the manufacturing process, the method comprising: providing the loading unit, the loading unit comprising: a tool assembly including: a cartridge assembly including a staple cartridge having a tissue facing surface, a plurality of staple retaining pockets and a knife slot formed in the tissue facing surface thereof; a plurality of surgical fasteners loaded one each in the staple retaining pockets; and an anvil assembly in juxtaposed relation to the cartridge assembly, the anvil assembly including an anvil plate having a tissue facing surface defining a plurality of staple forming pockets and a knife slot therein, at least one of the cartridge assembly or the anvil assembly being movable in relation to the other of the cartridge assembly and the anvil assembly; the method further comprising: providing the surgical buttress (B1, B2); applying the surgical buttress to the tissue facing surface of at least one of the cartridge assembly or the anvil assembly; applying heat and pressure on the respective cartridge assembly or anvil assembly so that the topography of the surgical buttress conforms to the shape of the tissue facing surface by deforming the surgical buttress into the staple retaining pockets and the knife slot of the cartridge assembly or the staple forming pockets and the knife slot of the anvil assembly to which the surgical buttress is applied, thereby increasing the contact area between the surgical buttress and the tissue facing surface; wherein the surgical buttress is made wider than a width of the respective cartridge assembly or anvil assembly so that lateral edges of the surgical buttress extend partially around the circumference and beyond a lateral side edge of the respective cartridge assembly and/or anvil assembly. a cartridge assembly including a staple cartridge having a tissue facing surface, a plurality of staple retaining pockets and a knife slot formed in the tissue facing surface thereof; a plurality of surgical fasteners loaded one each in the staple retaining pockets; and an anvil assembly in juxtaposed relation to the cartridge assembly, the anvil assembly including an anvil plate having a tissue facing surface defining a plurality of staple forming pockets and a knife slot therein, at least one of the cartridge assembly or the anvil assembly being movable in relation to the other of the cartridge assembly and the anvil assembly; the method further comprising: providing the surgical buttress (B1, B2); applying the surgical buttress to the tissue facing surface of at least one of the cartridge assembly or the anvil assembly; applying heat and pressure on the respective cartridge assembly or anvil assembly so that the topography of the surgical buttress conforms to the shape of the tissue facing surface by deforming the surgical buttress into the staple retaining pockets and the knife slot of the cartridge assembly or the staple forming pockets and the knife slot of the anvil assembly to which the surgical buttress is applied, thereby increasing the contact area between the surgical buttress and the tissue facing surface; wherein the surgical buttress is made wider than a width of the respective cartridge assembly or anvil assembly so that lateral edges of the surgical buttress extend partially around the circumference and beyond a lateral side edge of the respective cartridge assembly and/or anvil assembly. providing the surgical buttress (B1, B2); applying the surgical buttress to the tissue facing surface of at least one of the cartridge assembly or the anvil assembly; applying heat and pressure on the respective cartridge assembly or anvil assembly so that the topography of the surgical buttress conforms to the shape of the tissue facing surface by deforming the surgical buttress into the staple retaining pockets and the knife slot of the cartridge assembly or the staple forming pockets and the knife slot of the anvil assembly to which the surgical buttress is applied, thereby increasing the contact area between the surgical buttress and the tissue facing surface; wherein the surgical buttress is made wider than a width of the respective cartridge assembly or anvil assembly so that lateral edges of the surgical buttress extend partially around the circumference and beyond a lateral side edge of the respective cartridge assembly and/or anvil assembly.