Look for these warning signs: visible cracks in the masonry, white staining (efflorescence) on exterior bricks, water stains on walls or ceilings near the fireplace, or a chimney that’s leaning even slightly.
Inside, you might notice rust on the damper, cracked flue tiles, or a strong odor coming from the fireplace even when it’s not in use. If you’re getting water in your firebox during storms or see chunks of mortar in your yard after winter, those are clear replacement indicators.
The deciding factor is often cost—when repair estimates approach 50% of replacement cost, or when you’re facing multiple major repairs, replacement gives you better long-term value and eliminates ongoing safety concerns.