Fired clay was mainly restricted to roofing tiles and associated decorations, but these were quite elaborate. The roof tiles allow a low roof pitch characteristic of ancient Greek architecture. Fired bricks began to be employed with lime mortar. Very prominent buildings were roofed in stone tiles, which mimicked the form of their terracotta counterparts. While later cultures tended to construct their stone buildings with thin skins of finished stones over rubble cores, the Greeks tended to build out of large cut blocks, joined with metal cramps. This was a slow, expensive and laborious process which limited the number of buildings that could be constructed. The metal cramps often failed through corrosion.