"The Nolichuckey River is a nearby mountain river," said Principal Architect James F. Williamson, AIA, of Williamson Pounders Architects (WPA) in Memphis, TN. "They have been dredging stone from the river for more than 100 years. [The church] has been a landmark in downtown Johnson City for most of that time - mainly for its eccentric use of stone. It's known locally as the 'Rock Church.' "

When describing the original architecture of St. John's, the architect explained that the exterior looks as though it is composed of large pebbles. "When I say pebbles, I mean stone that has been rounded by the water," he said. "When we were ready to do the new nave, everybody was very interested in the possibility of building with the same river rock. We did a little research, and then some Church members found the company that supplied the original stone. It was still in business, so the stone came from the original site."