FOREST PARK, Ga. -- Security gates slowed down Clayton County firefighters rushing to a three alarm apartment fire late Monday night.

SLIDESHOW: 3-Alarm Fire Destroys Apartment Building

Management recently installed the gates at the Laurel Point Apartments on Johnson Road, but they failed to notify the fire department.

When fire trucks rolled up to the complex they couldn't get in.

After a delay, residents directed them to an open gate.

"All the entrances were blocked off, so I had to tell the firemen to go on down; they couldn't get in this entrance," said apartment resident Sheila Evans. "By the time they got in, the fire was out of control."

Flames had spread throughout one apartment building.

That building was under renovation and no one was living in any of the units.

The age of the building contributed to the firefighter's problems.

"This building was built back before sprinklers were mandatory," said Clayton County Fire Department Chief Alex Cohilas.

There's no word yet on the cause of the blaze.