Candle soot vs fire soot microscopy

Candle Soot vs. Fire Soot: Why They Leave Different Stains and Require Different Fixes

Candle soot is oily and sticks to surfaces differently than fire soot — and cleaning one the wrong way makes it worse. Learn what sets them apart so you don’t cause more damage trying to clean up.

A white residential ceiling exhibits distinct dark, parallel stripes, often found along joist lines. This clear visual demonstrates thermal tracking, or 'ghosting,' where soot and dust adhere to colder surfaces, as explained in our article: 'Thermal Tracking ‘Ghosting’: Why Your Walls Have Black Stripes'.

Black Lines on Your Walls and Ceiling? It’s Probably “Thermal Ghosting” — Not Mold

Perfectly straight black lines running along ceiling joists or wall studs are almost always “thermal tracking” — soot deposited on cold spots in your framing, not mold. Learn what causes it, how to tell the difference, and whether you need a pro.