Abstract: A nailable floor panel structure including a plurality of generally inverted-channel shaped parallel floor planks with depending flanges disposedly downwardly in generally abutting relation, and generally linear end caps affixed and rigidly interconnecting the respective ends of the panel planks. Each end cap includes longitudinally spaced, laterally offset portions corresponding to the floor plank junctures, and cut-out portions at the ends of the cap conforming in shape to the depending flanges of the channel-shaped floor planks. The design provides enhanced structural integrity of the finished floor panel and facilitates modular fabrication of the finished panel.