
High-altitude freezes every night. What does that do to masonry?
- Crown cracks that seem to grow every spring
- Joints opening on the sun-facing side first
- A chimney that ages faster than the house around it
Why it happens in Wyoming: Cheyenne crosses freezing over 140 times a year, the highest count we measured in any state, but in air dry enough that sound masonry mostly shrugs it off. The chimney with an open crown or joint is another story: at this altitude the freeze finds it nightly. Condition is everything; the weather supplies the test.
What fixes it, and what it costs
At altitude the freeze-thaw cycle can run nightly for months (strong sun thaws what clear nights refreeze), so condition is everything: a sound crown with an overhang, tight joints, and a breathable water repellent once they are sound. The same chimney that suffers open-jointed will shrug the altitude off maintained. The mountain supplies the test either way.
- Flexible seal over a sound crown
- $200–$500
- Localised patch repair
- $300–$700

























