Chimney Crown Repair
How often do you need to inspect your fireplace chimney? Inspecting it at least once a year will keep your fireplace chimney in good working order. If loose brick or a cracked chimney crown are not repaired, they can lead to much larger repairs later on. Water is the number one reason why fireplace chimneys need maintenance and repair. One of the best ways to inspect your chimney is from up on the roof of your house, but most people don't like climbing ladders and getting out on the roof, especially if the roof is steep. The next best way to inspect your chimney is simply to step back from the chimney to a point that you can view the whole chimney. Using a pair of field glasses, look for any loose or broken brick. Next, look for any moss or dark discoloring of the brick or stone facing. If a chimney is in good shape, the brick should all be uniform in color. On most all chimneys, the first part to fail will be the mortar crown. There are two things wrong with this. First, the mortar crown is the hardest part of the chimney to see and inspect. The next thing about the mortar crown is that it's your chimneys first line of defense against letting water penetrate into it. Last but not least, is the fact that a mortar crown should never be made of mortar, it should be made of concrete.
Building your chimney crown out of concrete, will extend the life of your fireplace for many years. Especially if you create a drip edge of at least one inch all the way around the face of the brick chimney. This way, the water that falls on top of the chimney will run off the concrete crown and fall to the ground without running down the face of your chimney. This one thing will add extra life to your chimney, in that it will stay drier, and keep your brick in better shape. The number two problem that we see on chimneys, is loose or missing chimney flashing. Your flashing is what keeps water from entering into your roof were the chimney and roof meet. A poor flashing job can ruin a new fireplace chimney or the roof its self. Many times when a homeowner has a roof replaced, they don't replace the flashing on the chimney. They just replace the roof flashing. This can lead to problems down the line.
The firebox and damper are the next two areas on a chimney that we have to repair or replace. This usually happens when the fireplace or chimney has not been maintained properly. As we discussed earlier, water is a chimney's worst enemy. Especially here in the Seattle area where we have months of hard rain. To stop this water from penetrating, the masonry chimneys crown must not let water in. Next, every fireplace chimney should have a rain cap that installs over the top of the flue liner. This will serve several purposes. The most important one is, it will stop rain from going down the flue liner and soaking the firebox with large amounts rainwater. If you can imagine what happens to the firebrick when there is frozen water on one side of the firebox, and a hot burning fire on the other side. A rain cap over the flue liner will keep the damper in your fireplace chimney from rusting out. This is also one of the major repairs that chimney's need when we go out to inspect them. A little maintenance will go a long way. You can help yourself and have many good years of enjoyment from your fireplace chimney.