A Lancaster jury returned three more guilty verdicts on Friday against 59-year-old Alan Kimble Fahey, after convicting him of nine others Wednesday. Jurors deadlocked on three more counts.
Ten of the misdemeanor convictions are for maintaining illegal structures.
Fahey, a retired telephone service technician, began building Phonehenge West in 1984 on his Mojave Desert property.
It has grown to include a barn where he lives, another structure that resembles a railroad car, and a 70-foot tower with stained-glass windows.
He says the structures are art, but authorities say they are a safety hazard.
The Associated Press contributed to this report.