Abstract: A molded siding member for use on buildings composed of a plurality of vertically extending panels connected side by side by intervening webs to simulate a horizontal course of spaced shingles, the member being formed along its upper margin with nail receiving recesses molded into its exterior surface to form bosses protruding inwardly a predetermined distance to engage the side of the building and thereby provide a predetermined spacing of the said upper margin outwardly from the side of the building when the member is nailed in place, the member being formed with protruding portions extending downwardly below its lower margin to form locking tongues adapted to be inserted in the space between the building and the upper margin of the next lower member to lock the lower margin of the upper member in place in readiness for a simple nailing operation at its upper margin.