The building material is stone sourced from nearby cell tower construction sites and hand-carried uphill from ¼ mile away. The project adheres to East Bay Regional Parks District Rules and Regulations (Ordinance 38 section 805):
“No person shall damage, injure, collect or remove earth, rocks, sand, gravel, fossils, minerals, features of caves, or any article or artifact of geological interest or value located on District parklands.”