Soot and Other Black Stains
by Arnie Katz
Q: We moved into our new home about four months ago, and love the house, but there are black stains appearing in the carpet along the edge of the walls and under bedroom doors. There are also stains on the refrigerator, and when I wipe the screen of my TV, the cloth is covered with black. Our builder insists it's not a problem with the house, and the heating contractor claims everything is working properly. My uncle, who's a doctor, says it's mold & mildew, and could be a health threat. My brother, who's a builder, says it's just dirt from all the construction activity in the neighborhood, and it will clear up once the construction stops. And my sister insists it's soot from the candles we burn. How can we find out for sure?
A: First, the bad news. Based on your description, any-or all! -of your relatives may be right. The good news is that it's often possible to solve these problems without spending huge sums.
You're already on the right track. The best first step is often figuring out what the material is that's causing the stains. Mildew and molds tend to form on damp surfaces, or places where warm, moist air hits a cold surface and condenses. It also tends to have a characteristic "moldy" smell to it.
Dirt coming into the house tends to be lighter in color than black, unless you've got black soil in the neighborhood. You can usually wipe it up with a damp cloth. Soot, on the other hand, is black black, and if you try to wipe it you wind up feeling like Dennis the Menace trying to glue the smashed cookie jar back together: the more you do, the worse it gets. Soot tends to be oily, and it smears.
There has been a dramatic increase in soot staining of homes in the last couple of years. Any time we burn something in the house, there is the potential for soot production. If the combustion products aren't vented to the outside, then we can get soot deposits in the house.
Common sources of soot include:
Your first challenge is to figure out the source(s) of the soot in your house. Based on a number of soot investigations that we and others around the country have done in the last two years, it's quite possible that your sister is right-the soot may very well be caused by your candles.
At this point we know that some types of candles produce soot, and in some homes, due to the air leakage characteristics of the house, the soot winds up deposited on the carpet along the baseboards of interior walls. Soot is typically attracted to plastic surfaces, and we've even found it inside refrigerators. In some homes it deposits on walls, and produces "ghosting" stains that outline pictures or even the studs in the wall frame. Sometimes it deposits on floors and stains the carpet under frequently closed interior doors or along the base of draperies or bed skirts.
People have been burning candles in their homes for hundreds of years, so it's fair to ask why this is happening now. As we explore the problem, we're coming up with more questions than answers:
Some articles indicate that the candle industry in our country has doubled in the last five years. Is this simply a decorating fad, or are odors increasing in our houses to the point that we need to cover them up?
The easiest way to determine if candles are the cause of your soot problem is to clean the stained areas and stop burning any candles for a couple of months. If the soot doesn't return, you may have solved the problem. To make sure, you could start burning them again for a couple of months, and see what happens.