The walls of ashlar tufo blocks appear to have been built by covering the bedrock with soil and using this soil as foundation for the blocks and preparation for floors situated between the walls. The original wall of the wall can be seen to the length of 10.73, but tufo blocks are only present to the length of 8.87 m. The blocks have obviously been robbed, but the extent of the tufo floor (SU 1216) and a little ridge in the bedrock indicate it's original extent.