What It Does

The chimney crown is the concrete or mortar “roof” that covers the very top of your chimney. Its job is to keep water from soaking into the masonry below. A good crown is slightly sloped so rain runs off and overhangs the edges just enough to keep drips off the brickwork.

When it’s built right, it quietly protects your chimney for years. When it’s built wrong or starts to crack, water finds its way inside fast.

What Can Go Wrong

Common trouble signs:

• Hairline or larger cracks across the surface
• Pooled or standing water on top
• No overhang or a flat top that traps moisture
• Flaking or crumbling at the edges

Once water seeps through those cracks, it can damage the brick, rust the flue, and even leak into your attic or walls.

How the Pros Fix It

A chimney sweep will inspect the crown for cracks and poor drainage. Small cracks can often be sealed with a flexible waterproof coating that moves with temperature changes instead of cracking again.

If the crown is too thin or severely damaged, it can be resurfaced or rebuilt using stronger, longer-lasting materials. Many sweeps use CrownCoat or CrownSeal, both professional-grade coatings that create a watertight, elastic membrane over the crown surface to stop leaks before they start.

The Products They Trust

CrownCoat: A brush-on sealant that forms a durable, flexible waterproof layer over the crown. It prevents cracks and leaks caused by rain, snow, and freeze-thaw cycles.

CrownSeal: A thicker, trowel-grade material that’s ideal for repairing crowns with deeper cracks. It cures into a long-lasting, waterproof membrane that moves with the chimney instead of cracking.