CLEBURNE (CBSDFW.COM) – At the Garza Building in downtown Cleburne, bricks protrude out toward the street and the side of the three-story structure appears to be leaning.

That’s what fire chief Clint Ishmael noticed while he was in front of the building on Memorial Day.

When he took a ladder truck back Tuesday for a closer look, he was able to pull a brick right out of the wall. And when he looked inside, dozens of eyes looked right back at him: The entire wall was filled with bats.

There are so many that, over time, their droppings have frozen and thawed, expanding the wall, causing it to crack and fall apart.

“You drive by these buildings every day and unless you’re actually looking for it, it’s difficult to detect,” Ishmael said.

When he took a CBS11 crew back up to the wall Wednesday, the bats weren’t in the same spot, but appeared to have burrowed even deeper into the wall.

An ammonia-like smell coming from the cracks was overwhelming.

Building owner Frank Garza said high school students and groups who rent the building, which was built in 1866, have told him they had seen swarms of bats in the early morning hours.

But the second and third floors are vacant, and no one ever noticed the bats building a home in the walls.

Garza, who runs a restaurant called Chigo Hotdogs on the first floor, has to find a way to repair the building. Bricks could fall onto the sidewalk at any time.

However, first he and his son Casey have to figure out a way to remove the bats.

“I don’t know anybody off the top of my head I can call and say, ‘Hey I have a thousand bats, what can you do?'” Casey said.

Ishmael said it’s not unusual to have older buildings in the city develop structural problems, but this is the first time in 20 years he said he had seen bats cause the damage.