Concrete Chimney Crown
The crown of your chimney is the topmost portion of a masonry chimney. This makes it the first line of defense from the elements. Cracked or deteriorate crowns will allow what into the chimney and eventually into your home.
Most chimneys built before 2010 have what’s called a mortar wash or splay, this is when the mason uses mortar (sometimes reinforced with horsehair of fibers) and slopes it up from brick edge to flue tile. This generally cracks within 10-15 years and begins allowing water into the chimney.
Wisconsin’s current codes require a minimum 4” thick and it must overhang the sides of the chimney by at least 1 ½”, there must also be an expansion joint between the flue tiles and the concrete.
Our crowns are poured with 4000psi strength concrete with added rebar re-enforcement, they are 5 ½” thick with a 2” 0verhang, we meet Wisconsin’s expansion joint requirements and go one step further with a bond break between the bricks and concrete.
We do this because concrete and bricks fluctuate at different temperature points, which means when the bricks begin the expand from the heat in the summer the concrete does not, these opposing forces cause the bricks to crack or separate from their mortar bond.
To finish it all off we have a drip grove underneath the overhang to stop water from making it to the brick face.