Into the "fossa" was dumped large amounts of rubble, gravel and stone, whatever fill was available. Sometimes a layer of sand was put down, if it could be found. When it came to within 1 yd (1 m) or so of the surface it was covered with gravel and tamped down, a process called "pavire", or "pavimentare". The flat surface was then the "pavimentum". It could be used as the road, or additional layers could be constructed. A "statumen" or "foundation" of flat stones set in cement might support the additional layers.