Fire investigators are looking into what caused a fire at a Hamilton County business.

Varnell Construction Company on Highway 58 caught fire early Saturday morning. 

When firefighters got there, they say half of the building was on fire.

They got the blaze under control in about 20 minutes, but it had already caused $80,000 in damage.

Firefighters say the fire started in the office.

They say it does not look suspicious.