Your chimney has a Houston problem, not a chimney problem.

Creosote deposits absorb humidity and release it back into the room, which is why the smell usually arrives with the warm weather rather than the burning season. Negative pressure in the house then pulls that air down the flue instead of up it. Both are fixable. See fireplace odor removal.

One of four places: the crown, the flashing, the cap, or the masonry itself. They look identical from inside the house and cost very different amounts to fix, which is why we test before quoting rather than after. Start with a leak inspection.

A general home inspection does not cover the inside of a flue. Property transfer is one of the situations that calls for a Level 2 inspection with a camera scan, and finding a defect during closing is far more expensive than finding it before listing.

The species decides everything. Chimney swifts are protected under federal law while nesting and cannot be removed until the season ends. Mammals often have young in spring, and removing the adult without the juveniles creates a worse problem. We identify first, then remove, then cap so it cannot happen again. See chimney animal removal.