Neighbors watch with concern as man builds circular sandbag house in their St. Louis neighborhood

ST.  LOUIS -- A home under construction site in the western part of St. Louis is creating quite a spectacle and concerning some of its neighbors.

Zachary Kraft is building a circular home that's what he calls 'a rammed adobe earth bag structure.'

That means walls are made from stacks of sandbags filled with natural materials.  He said the concept is popular in the southwest part of the United States, and creates homes that are extremely energy efficient.

“I think a lot of people have been thinking it’s a bomb shelter or something like that,” Kraft told FOX 2 News in St. Louis. “People live in them and they’re awesome,” said Kraft.  “It can be extreme temperatures, very cold, very hot and that’s what people want to live in.”

Kraft received a building permit but will need to pass further inspections in order to obtain an occupancy permit.

Watch the video above for neighbors' comments critical of the city and the construction.