Chimney Crown Repair

Chimney Crown Repair — Your First Defense Against Water

The chimney crown is the concrete or mortar cap that sits on top of your chimney, sealing the gap between the flue liner and the outside edge of the chimney. It's your chimney's first line of defense against water entry from above — and it's one of the most commonly damaged chimney components we see.

Why Chimney Crowns Crack

Most chimney crowns are built with standard mortar rather than proper crown mix — a cost-cutting shortcut during construction that leads to premature failure. Without expansion joints, thermal expansion and contraction cause cracking. Water enters these cracks, freezes, expands, and creates larger cracks. Within a few years, a crown built with improper materials begins allowing significant water entry.

Levels of Crown Repair

Crown sealing is appropriate for crowns with minor hairline cracks. We apply flexible, waterproof sealant that bridges cracks and prevents water entry. Crown coating involves applying a thick, flexible membrane over the entire crown surface, providing years of waterproof protection. Crown rebuilding is necessary when cracks are extensive, pieces are missing, or the crown is structurally unsound. We remove the old crown completely and rebuild with proper crown mix including expansion joints.

Building a Crown That Lasts

When we rebuild a crown, we do it right: Portland cement-based crown mix (not mortar), minimum 3-inch thickness, proper slope away from the flue, a 2-inch overhang with a drip edge, and expansion joints where the crown meets the flue liner. This construction prevents the cracking that plagues improperly built crowns.