WALTHAM, MA - A reported building fire at 173 Charles Street in Waltham sent Engines 1, 2 and 4, Squad 5, Rescue 1 and Ladder 2 to the scene. Engine 4 first due reported heavy fire coming out the first-floor windows and requested a working fire. Companies knocked the fire down on the first-floor, but fire continued to the second-floor where it was running up the exterior. It took firefighters about one hour to knock it down, and they were on the scene for about two hours. One resident needed assistance from the Red Cross. There were no injuries.