Dark-colored ceiling stains

50+ Y.O. 1-story/rambler with drywall finishes, little to none insulation in attic, & a wood-burning stove…Dark stains were observed in a pattern that followed ceiling joists in an outline with darkest areas being the closest to exterior walls, away from wood stove in center of house…Some areas showing darker on joists & other areas, on the opposite side of wall from wood stove, showed darker bays & lighter on joists…No moisture was present when tested with meter, and dark areas on ceilings could be cleaned/wiped off with wet rag…After wiping, rag had a mild odor of smoke & candle/incense-type fragrance. (See attached photos)
MY THEORY: Due to limited insulation in attic, thermal transfer is occurring through framing, and when wood and/or candles or incense are being burned, warm air, capable of carrying more humidity/moisture than cold air, is attracted to the coldest areas of thermal transfer & heat movement, and airborne soot collected on condensation created by rapid cooling of warm air in cold spots.

Has anyone witnessed/observed this phenomenon before? My client has expressed concern & any extra input would be greatly appreciated.

I think you diagnosed the condition accurately. It’s called “ghosting.” Good call.

“Ghosting” can just be cleaned & painted then. We are in Seattle/northwest area, so the lack of insulation is the underlying issue, especially from an energy standpoint. Thanks for the input.

It can also happen with and oil burning appliance which is called a puff back. Having cleaned many puff backs in the restoration business, I can tell you that I have seen them in many forms. Insurance will pay to have them cleaned. You typically find ghosting at the points of convection such as over and under windows, joists, and at the high corners of rooms. Nail and screw heads will also show up. This can also happen due to candle damage. People who burn a significant amount of candles will create this damage as well. Specially, if they are not high quality and have lead in the wicks. In all cases, a stain blocking primer is necessary before painting. Or else the ghosting will happen back through the paint. Often, it will not clean off surfaces readily, if at all (wall paper and textured finishes for certain). When you are in a home , if there are no oil or wood burning appliances, always ask if they burn candles.

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