We may purchase a house built in 2004. There are dark smudges on the drywall where ceiling joists are.?
Filed in Chinese Drywall Feedback on Sep.19, 2011
We wonder what has caused these. The current owner says she has burned a lot of candles and the joists magnetically attract the smoke from the candles?? Don’t know if they are wood or maybe steel. Any suggestions? Chinese drywall? Metal studs??
September 19th, 2011 at 3:41 pm
Could be from candle smoke.Also check for any leaks.
September 19th, 2011 at 4:17 pm
It is possible that the joists could have made the ceiling colder right under them. If the ceiling is insulated with anything greater than R4 (the thickness of the 2×4 joists), then it would be warmer while the joists would be colder (the “R” rating is supposed to approximate the insulation quality of solid wood). These colder areas might have allowed the carbon particles to adhere better than the warmer spots.
September 19th, 2011 at 4:49 pm
That is quite common in a smoky environment – convection at even slight irregularities on the ceiling will cause additional build-up at the points of turbulence – and it is static electricity attraction, so “magnetism” is not far off as a descriptive. It really does not take much.
At the same time, if there is enough build up to see smudges, it is quite possible that you have a thin layer of paraffin (what we call the primary component of commercial candle-wax in the US) everywhere in the house which will make painting difficult in the future – unless you prime with a very good oil-based primer (Kilz comes to mind). Kerosene heaters do the same thing only much, much worse.
You can test for this using two small plant sprayers. From a distance of about 15cm (6 inches) spray the ceiling lightly. If the water beads up, there is a fine wax/oil coating. If not, you are OK. If your owner resists that diagnosis, the second plant sprayer should be filled with water but with the addition of a few drops of liquid dish detergent. That will spread normally and not bead up. Showing the difference.
September 19th, 2011 at 5:28 pm
Yes it is probably from the candle use (could be mildew, but probably not) if it is the candles you have spot prime them with a stain blocking primer and repaint the areas.
September 19th, 2011 at 6:20 pm
Candle smoke, incense and a fireplace (real fireplace that burns actual wood) can all do that. The reason its at the joints, is because that’s where the smoke concentrates as it tries to disperse indoors. If it’s that worrisome, have a home inspector come check it out. The stains won’t come out, per say, but a fresh coat of paint will make them disappear