An extrusion die for forming polymeric foam sheets includes a first die body, a second die body, and a manifold within the first die body and the second die body, wherein the manifold includes an inlet to receive polymeric material. The extrusion die further includes a die exit formed by opposing die lips in fluid communication with the manifold and a temperature control zone adjacent the die lips. The extrusion die further includes two generally planar shaping surfaces in proximity to the die exit and place one above and one below the die exit. Adjustable shoes are disposed in proximity to the die exit on each side of the die exit and between the planar shaping surfaces.