Chimney Flashing Repair
Chimney flashing is one of the essential parts of a chimney. In that, it defends the area around the chimney from leaking water, where the roof meets the chimney. It also is one of the most overlooked areas in the maintenance of a home. Chimney flashing is your first line of defense against water damage. It's also your last line of defense. If water gets past your chimney flashing, there is nothing to stop it from penetrating your walls and ceilings. We get quite a bit of rainwater every year. Whether you have a fireplace that is built of masonry stone or brick, you will have to maintain the chimney flashing. Chimney flashing is able to last about 20 years, due to the amount of wear and tear in our weather patterns.Many of the fireplace chimneys that I see have the same chimney flashing that they were built with. Many of these are over 50 years old and failing. Most of the time this can be fixed by cutting out the old metal flashing with an angle grinder and replacing it with new chimney flashing. The next thing that we would consider, is the bricks that are above the chimney flashing. Do they need to be repaired? Do they have missing mortar joints? Do they need to be repaired and re-tuckpointed? Tuckpointing is done so the water cannot bypass the chimney flashing. Last but not least almost every fireplace crown needs to be check for cracks. Chimney crown cracks are one of the primary reasons that chimneys can leak past the chimney flashing.
In the picture above, you see an example of a chimney that has been restored by cutting out all the old flashing and replacing it with new flashing. This chimney is over 50 years old. It's as good as the day that it was built. All the brick has been repointed with new mortar joints and cleaned and sealed. But the most important part of this chimney restoration is the new concrete crown that is placed at the top of the chimney if you look close at the picture above, you will see that this new concrete crown is approx. 4 inches thick. This is a lifetime chimney crown. It's quite different in that almost all chimney crowns are constructed out of mortar when they are being built. This will only last a few years without extra maintenance. With this concrete crown at the top of this chimney, it is actually better than the day that it was built. A brick chimney can last for hundreds of years if it has been constructed right and maintained. A brick chimney is meant to absorb a certain amount of water and then dry back out by breathing in and out the normal amount of water. That is why it is essential that the chimney or fireplace flashing is in place and working to stop any excess water from entering in through the chimney walls and into the rest of your home. Remember that a chimneys flashing stands alone, and has no backup system to stop water from damaging your walls and ceiling. It would be a good idea to check your chimney flashing every few years, to make sure that it's in good condition.
As a masonry contractor here in the Seattle area for over 25 years, we have repaired thousands of brick and stone chimney for our many customers, and we always repair them in a way that they should have been built to start with. By this, I expect that if a chimney flashing is not installed right we will cut it out and reinstall it in an accurate way. One of the most substantial problems that we see in chimney flashing is that the flashing is not stepped right. Chimney flashing needs to be stepped with at least a 2-inch overlap from piece to piece. The higher piece always overlapping the lower piece. This is also true of how much you want to overlap the roof flashing. As it needs to have at least a 2-inch lap to prevent water from getting by the flashing. Last but not least, if your chimney is more then 2 feet wide it is a good idea to place a cricket behind the upper side of the chimney. This is a small peaked roof that will kick the water out from behind your chimney. This is a little tricker than just a regular roof because both the cricket and the chimney need to be flashed where they meet. Let's talk about how long a repair flashing or chimney tuckpointing should last. As I said above, we have been repairing chimneys and fireplaces for over 25 years in the Seattle area, and we have yet to go back and redo any chimney or fireplace that we had previously rebuilt. This is not that amazing if a chimney is built right. It can last a lifetime and more with just a little maintenance. Please give us a call if your chimney is in need of help and I will come out and give you a free chimney inspection.