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Professional Chimney Sweeping
A build up of creosote in a chimney is a very dangerous situation and can cause chimney fires so bad it could destroy the house The reason for this is as it burns, it expands and can the chimney in the attic to fail.
The chimney sweep just left, but not before telling you, “You have a very serious third stage creosote problem”
What on earth is that ? Well seeing is believing so first grab a flashlight, go to your fireplace or chimney inspection hole, and take a look. Your flue's insides probably look like a black mirror, witch shines, slick deposits on the wall that look almost painted on, giving the appearance of black ice or black bathroom tiles. That's third degree creosote.
To understand why it brings a grim look to your sweeps face, a little more explanation is in order. Creosote, as you know, is the black sticky substance that's produced whenever wood is burned. It is a natural by product, and its flammable, which is why you called your sweep to remove it in the first place.
But when it condenses on the inside of your chimney, it can take a number of forms, most of which fall into three categories.
First stage: The most common, people usually call it soot. It's a light powder, if you look on your chimney sweeps face you'll probably see some.
Second stage: Looks like pumice stone from a volcano or black potatoes chips or a burnt marshmallow, usually light and airy. Third stage: Similar to a black bathroom tile, black ice or an asphalted road. A very hard shiny glaze. The most dangerous and difficult to clean. Your chimney sweep can do an excellent job on first and second stage creosote by using a series of wire brushes designed to fit your chimney and stove pipes.
Third stage creosote is a totally different animal. It is easiest to understand why your sweep's wire brushes are not effective on it, when you realise that not only does it look like a black mirror, but it has many of the same qualities. The wire brush rubbed across a mirror would only slightly scratch the surface, basically the mirror would be unchanged. What makes third degree creosote so dangerous? First when its heated in a chimney fire it mushrooms far beyond its original size. As it expands across your chimney it can choke the flue, causing the fire to find a new way to exhaust it's fumes. This new avenue of exhaust often is through your attic or roof. On occasion, pieces of a chimney have been blown out by the tremendous pressure exerted from this expansion. And a third stage driven fire is so hot that it easily exceeds the temperature limits for which the chimney was designed, thereby damaging the chimney. Such chimney fires routinely exceed the temperatures of a blow torch.