How to Identify CreosoteMarks or stains on your roof can be an indicator of a pressing and dangerous problem called creosote. This build up of soot inside your chimney or stove pipe can pose a serious risk of fire and must be removed right away. It’s important to know the signs that creosote presents and to act quickly once the indications are found. Creosote is a sticky substance that hardens to a crust on the liner of your chimney or stove pipe. That condition then builds up into the flue and runs through the chimney cap when rain and snow are in the air. This results in stains on your roof shingles. Where are the Creosote Stains? You can tell that the dirty soot is coming from your chimney by the location of the stains. Shingles around the area and in the sloped pathway of the roof are a clear indication. How Large are the Creosote Stains? The size is dependent on the size of your chimney and the amount of creosote build up that has reached the flue. Keep in mind that any minimal creosote build up should be removed immediately and your chimney should be cleaned on an annual basis to avoid chimney and house fires. Gas or Wood BurningWhether your fireplace uses gas or wood fuel, black stains on the roofing materials are an indication of trouble. Any build up of creosote must be looked after to provide a safe atmosphere inside your home.