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.