The homeowners just purchased their Owings Mill, MD home and they knew from the home inspection that the chimney needed some masonry repairs. As you can see the bricks are spalling (spalling happens when moisture gets into the bricks freezes and pops the brick faces out). This crown was in a condition similar to a chimney project that we rebuilt in Ellicott City.
Why the home needed a chimney rebuild?
This happens because of the design flaws in the construction of the chimney. Below is I will list some of the flaws based on the arrows.
Green arrow– They did not install an expansion joint around the flue liners. When the flue is in use and heat is going through it, it will expand. Without an expansion joint the flue liners will eventually crack the crown as they expand during the heating process. You can see that has happened here with the large cracks running from the chimney liners to the edge of the crown.
Yellow arrow– The crown is pitched to the edge of the bricks leaving it fragile. The crown itself isn’t thick enough, to begin with, but when they pitched it off to the edges it leaves a very thin surface where water will collect, freeze and crack the edges.
Red arrow– The bricks at the top of the chimney are corbelled inwards (stepped in). This leaves a place for water to sit and soak into the chimney. This is also a place where you can have vegetation growing on the chimney like the one above. The vegetation can and will have the roots destroy the chimney if left unattended.
All this damage to the to the top of the stack will also cause leaking into the fireplace. You can find out more about common causes of chimney leaks in our previous article.
How we rebuilt the chimney
When we build or rebuild chimneys, we will corbel the bricks out, and from there we will build a new floating cast concrete crown that sits on a stainless steel sheet, re-enforced with mesh and has the expansion joints around the flue liners. You can learn more about floating cast concrete crown here.
Once the chimney was rebuilt, we applied Chimney Saver waterproofing to prevent the same moisture issues from occurring.
Job Complete – Rebuilt Chimney
We also installed new counter flashing which in tucked into the mortar bed joints of the chimney.
Rebuild completed! We were able to get a pretty good match on the brick and mortar. Another satisfied customer from All Pro Chimney Service.