Chimney Crown Repair / Rebuild
The crown is the top surface that protects the masonry chimney walls. It serves to prevent moisture from seeping into the masonry chimney. Although both are very important, a crown is not the same as a chimney cap. A cap only covers the opening of the chimney flue, whereas the crown covers the entire top surface. The crown also serves to keep standing water away from this area and is built at a slant to send the water away from the center of the chimney.
Due to the location of the chimney cap high above the ground, you may not pay much attention to its condition. This is why our trained chimney specialists at Dubuque Fireplace and Patio take extra care to examine this chimney feature for you during our annual chimney inspection. A chimney crown in good condition is crucial for maintaining the integrity of your chimney because it’s the first line of defense against the weather.
The deterioration of a chimney crown is most commonly due to water and constantly changing temperatures that can cause cracks. These get worse with the continuous freezing and thawing cycles during the course of the year. Once the crown gets to a point of serious cracks or crumbling, the result will be many other problems for the house and chimney. If cracks exist in the crown, then water will be able to bypass the flashing which serves to protect against moisture in the area where the chimney and roof meet. Water is very damaging when it comes to finding its way into an opening! One way that you may notice a problem with the chimney crown is water marks on the ceiling around the area or drips in front of the fireplace.
Once the damage has occurred, there are a couple different ways to fix the chimney crown. If the structural integrity of the crown is still intact, then a strong bonding sealant can be used to fix any existing cracks and then a waterproof sealant can be used on top to further prevent against any more damage. The sealant will greatly extend the life of the repairs. Another way to fix minor cracks is to resurface the entire crown. This also works to keep the moisture out and also prevents against the existing cracks getting worse.
But for crumbing crowns or other serious structural problems, the crown must be completely rebuilt. At this point, it is beyond a simple repair. Typically chimney crowns are formed in place with cement and crafted into just the right shape and finish. Another thing to consider when rebuilding this feature is to use stronger materials the second time around, such as a crown reinforced with steel, or made from metal or stone. This will help the new structure last longer and prevent against future repairs.
With any type of Chimney Crown Repair, the most important aspect is to protect the chimney from
harsh weather and keep it closed off to all moisture. It is important to keep up with chimney
maintenance, even on the areas that you may not think about or even be able see from the ground.