‹‹‹ Vitr. 5.12.5 | Table of Contents | Vitr. 5.12.7 ›››
6But if the bottom be very soft, alder, olive, or oak piles, previously charred, must be driven, and the intervals between them filled with coals, as directed above for the foundations of theatres and walls. The wall is then raised with squared stones, the joints of which are to be as long as possible, in order that the middle stones may be well tied in. The inside of the wall is then filled with rubble or masonry; and on this, even a tower might be erected.
6But if the place proves to be soft, the bottom must be staked with piles made of charred alder or olive wood, and then filled in with charcoal as has been prescribed in the case of the foundations of theatres and the city wall. Finally, build the wall of dimension stone, with the bond stones as long as possible, so that particularly the stones in the middle may be held together by the joints. Then, fill the inside of the wall with broken stone or masonry. It will thus be possible for even a tower to be built upon it.