Replacing a Chimney Crown


A chimney crown is the cement that forms the top of your chimney. It acts as an "umbrella" to prevent water from pooling on the brick. This is important in the warmer times of the year because bricks are semi porous and allow water to leech into them. The bigger issue is what would happen in the winter during freezing temperatures.


Water that is allowed to penetrate a small gap will expand when it freezes, splitting or cracking the brick or cement. If this process is allowed to continue each winter it will eventually destroy the chimney.


We usually see this on chimneys that are 40 to 50 years old. Occasionally we'll see it on newer chimneys. What we are noticing a lot lately is that a repair attempt has been made and failed. Someone has tried to apply a thin layer of cement of a damaged crown and that new layer, because it is so thin fails in a few years.


The correct way is to remove the old crown, construct a form around the top of the chimney and install a new crown. It requires a little more effort but you end up with a crown that will last.


We recently replaced a crown that was showing some damage. You can see the old cement underneath the thin layer of cement. If the chimney had remained like that you can see where water would have entered and froze, causing more damage.



We placed tarps and sheets of plywood to protect the existing roof. Then we chipped away the old cement that formed the crown on the chimney. We then built a form around the chimney to pour the cement into. The most critical step is making sure the cement cures properly, insuring the crown won't need to be replaced again. If it's allowed to cure too fast it may even crack the same day. The key is to keep it most using towels and plastic.






Here is the completed crown. We put new stainless steel screens on after the picture was taken. The rest of the chimney is in excellent shape. We installed a new roof for the homeowner about six years ago. At that time the chimney was fine. It usually takes several years for a crown to show this much damage. The pace that the damage occurs accelerates as the cracks get bigger. Oftentimes you can see the damage from the ground.

If your bricks are "spalling" or breaking up and falling on the roof, you may require a complete rebuild. It's obviously much cheaper to replace the crown before it gets that far.




Schedule a Chimney Crown Repair Estimate!



roof express plus logo


rss feed




Copyright © 2012 All Rights Reserved.
Real Time Analytics