I was talking to my brother today and he was telling me that he had a chimney fire a few days ago. Sorry if this is a bit long but I want to explain everything. Chimney is a brick unit about 30ft tall that has a cast in place liner for the bottom ~15-20ft (supaflu) then the top part was rebuilt this summer with round clay tile and brick. 7" round opening from top to bottom. Long story short, they bought the house this spring and the chimney was unfit for use. It had an 8x12" flue that was not lined and it was coming apart. He hired a contractor to make repairs, he did the cast in place liner. Next came a next roof and come to find out the chimney guy didn't do the work correctly, the outside part was just "lipstick on a hog"! My brother hired another guy and they went ahead and rebuilt the chimney from the bottom of attic level up using a 7" round clay liner to match the cast in place liner. He is using a borrowed stove which is of unknown brand. It's fairly new, he thinks it was built in Minnesota if I remember right. It has maybe a 2 cu ft fire box and then the box is wrapped in metal and there is a duct that comes off the top to push the heat to wherever (cage blower under the stove). It's a "smoke dragon". I know he has 2 dampers inline on the stove pipe because the draft is really strong. (My Dad had to do that as well in his workshop) Wood he is burning is at least 2-3 years seasoned, maybe longer. He bought several cords from his father in law to get through for this winter. The FIL is like most of us where is he many years ahead with his wood. Burning roughly 24/7 and chimney has been cleaned it every 1-2 weeks. Everytime the stove gets emptied of ash the chimney gets cleaned. My brother uses a poly brush and does a bottom up cleaning. Poly brush because I guess the Supaflu would get damaged with a metal brush. The chimney fire happened when he was at home. He was working in the basement, pouring concrete to repair some floor damage. He opened the stove door to toss in a couple empty concrete bags and he got the freight train rumbling. At first just figured it was just from the draft, but he dialed it down and it continued and was getting worse. Went outside and 3-4ft flames where coming out the stack. It ended up going out on it's own as his friend was on his way with fire gear (small town and he is the closest volunteer firefighter) No damage in the end, all was ok. Cleaned the chimney out the next morning and pulled out about 3/4 full on a 5 gal pail! When he was cleaning it out before he would get a dustpan full, maybe a cup if that. That seemed normal, I wouldn't expect to have all that much creosote when burning good wood and cleaning often. Of course he is worried now. Did everything "by the book" and even well above and beyond with the flue cleaning and STILL had a fire. Any ideas on what might have caused this? Poly brush not working?