A fireplace can be a truly marvelous thing. They are usually the centerpiece of any living room they happen to be in. A fireplace provides ambiance, warmth, and mood, all while lowering your heating costs. But, to have one you must also have a big hole in your roof. This is where the potential for trouble comes in. This article will discuss the basics of getting a good, weather tight seal around your chimney.
When dealing with leaks, place flashing high on the list of usual suspects. It is the most common thing to go awry, and chimney leaks are no different. Flashing is sheet metal that keeps the transition between the chimney and the roof watertight. If water manages to get behind the flashing, it can do extensive damage to the roof decking, framing, and even the interior of your home. You will want this fixed immediately, in order to avoid expensive repairs.
To properly install flashing will require two layers. The first layer is called step flashing. L-shaped sections of sheet metal are woven into the shingle courses and lapped up the side of the chimney. The next layer of metal (counter-flashing) should be imbedded in the mortar joints of the chimney and folded down to cover the step flashing.
Even if installed by a skilled professional the corners will need a bit of extra attention. As the metal is cut and bent around the corners it leaves a very small gap that should be sealed with a quality urethane caulk. Please note that extra caulk is not a viable substitute for quality flashing work.