Crown cracks from river humidity and freeze-thaw
Why it happens here
Milltown sits right against the North Branch Raritan River, so the air stays humid and masonry dries slowly. When winter freezes that moisture, the concrete crown cracks. Once cracked, water runs straight into the flue.
Our approach
We rebuild crowns with chimney crown mix and a proper slope, not a thin patch. We also apply waterproofing sealant to the surrounding brick so the whole top of the chimney sheds water.