Fire crews have been at a builders merchant in Northfleet for a second night running.
More than 80 firefighters from all over Kent rushed to the blaze at Discount Builders Yard in the Botany Road industrial estate, when the fire started on Tuesday at 1am.
The building was almost entirely destroyed and was filled with wood and other building materials.
Two crews from Thames-side and a height vehicle stayed at the scene until 2.30am because materials were still smoldering.
Crew manager Dave Spittle of blue watch told News Shopper: "A lot of the metal buildings surrounding the builders yard had to be removed to stop the fire spreading.
"We are going back at 9.30am for another visit to make sure the area is safe.
"It was a really big job and all the crews involved did a really good job in making sure the fire did not spread to any other neighbouring buildings.
"It could easily have been a much worse scenario."
There were no confirmed reports of any injuries after the fire.
The owner of the building, who was at the scene, was said to be "devastated".