This house of a rural mail carrier and his wife is distinguished by the variety of concrete blocks that fashion its walls. Concrete block became a popular building material after Harmon S. Palmer patented a block-making machine in 1900, which after 1905 was sold by Sears, Roebuck and Company. Although the machine made only one block at a time, two men working together could produce as many as one hundred blocks per day. The Allen House showcases the great variety of textures the block maker could create simply by changing the faceplate in the mold. The most popular surface texture was the rock-faced block, which simulated stone. Here rock-faced blocks are laid with beaded mortar joints, giving them a solid formality. But small details make the building stand out. A line of concrete buttons, two per smooth-faced block, forms a border along a concrete cap marking the top of the slightly raised basement, and a course of closely spaced beads divides the first floor from the second. Triple rows of nailhead molding ornament the blocks at the corners. These classic block patterns lent themselves well to the house’s Colonial Revival design, characterized by a two-tiered portico and a hipped roof pierced by a pedimented dormer. The veranda’s Ionic columns on the first story and Tuscan columns on the second are cast in concrete.