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  1. #1
    Haze Smith Guest

    Default Residue on wall above baseboard heaters

    A couple of years ago, we added two bedrooms in the basement of a 30 yr old double-wide modular home. A month ago I ran into my customer, and she asked me to check out something happening to the wall above the baseboard heaters.

    There was a residue about 8" above the radiator that looks something like it looks if you hold a bic lighter against the wall: a whispy black trace of a flame. In addition, they couldn't wash it off. You could smudge it, but you couldn't get it all off the wall.

    No other heaters in the house but the ones we installed leave this residue. They are all heated by the same boiler.

    They tried to fix it by painting over it, but the residue reappeared. Just before I saw it, they replaced the old boiler with a new one, and painted the walls over -- again. They hoped their troubles were over.

    I saw Nicole in the grocery store today. Guess what? It's back. Any ideas? I'm stymied.

  2. #2
    Glenn Mitchell Guest

    Default Re: Residue on wall above baseboard heaters

    Are these people heavy smokers? The BBD heaters recirculate the air and just above the heaters would be concentrated

  3. #3
    Bob Patterson Guest

    Default Re: Residue on wall above baseboard heaters

    Residue above BB htrs is usually a result of incomplete combustion of something in the air (soot). Glenn has one of the most common reasons. Other things to look at are dust particles in the air or even dust bunnies. I noticed that your post says the problem is in the basement only. Take a real close look at the total ventilation in the rooms, you may need additional ventilation and/or air filtration. Another thing is that if you have soot on walls and you paint over it without sealing, it will bleed through.

  4. #4
    Michael OHandley Guest

    Default Re: Residue on wall above baseboard heaters


    Both good answers. If these are electric baseboard heaters they probably have a lot of dust or pet hair in them that is literally cooking and sending smoke up the wall.

    Of course, it could be good old fluid dynamics at work. Hot air from the heater is rising up along the wall at a slower speed than the colder descending air that is spreading out in that basement Dust particles (Which can be soot)suspended in that cold air are in motion down and out, when their direction is sharply changed by encountering the hot air. As the speed of those particles is accellerated and they attempt to change direction, centrifical force forces them to the outside of the airstream where they collide with the wall and are deposited on the finish. Same concept that old oil-filled air cleaners on combustion engines used up through the 50's to trap dust. Air carrying dust would rush into the air cleaner and be forced to rapidly and suddenly change direction. Centrifical force would carry the particles to the bottom of the filter reservoir where they would land in the oil and sink to the bottom.

    It will bleed through the paint until some type of pigmented shellac is used to seal it before painting.



  5. #5
    Bob H Guest

    Default Re: Residue on wall above baseboard heaters

    I've seen this on a lot of walls with bb units and assumed it was just pollutants concentrated by convection. I wonder if there is a particular coating on the ones you installed which distinguishes them from the others with no stains. I assume the reappearance is not a bleed through which could be remediated with shellac.

  6. #6
    Wayne Falcone Guest

    Default Re: Residue on wall above baseboard heaters

    Numerous possibilities and I agree, any of the previous suggestions could be the cause. If it is an ongoing condition, sealing over the stains will not cure the problem, you have to determine where the stains are coming from and address that cause. Some times there could be dampness in the carpeting that holds some dirt and then the dirt gets drawn up through the baseboard heat units staining the wall above the units. The staining could be mold or mildew bleeding thru the drywall, from water seepage into the foundation walls. Check the exterior grading to make sure the basement foundation walls are not getting damp or wet behind the finished walls.

    Enjoy Life !


  7. #7
    Arcosanti Guest

    Default Re: Residue on wall above baseboard heaters

    My wife ALWAYS has at least 1, sometimes up to 5 candles burning in our house. (I think she single-handedly is responsible for keeping Yankee Candle in business!) We have similar soot-type stains in our house, usually above outlets, especially in our kitchen. It almost looks as though our outlets are trying to catch on fire. I was told by a candle-maker that candles, especially cheap ones made with cheap wax, will produce that residue. Something to do with the soot particles bonding with ions from the electrical outlets or something.
    I just did a bathroom remodel for a "closet smoker" who would excuse herself to the bathroom to smoke her cigs. (I know that because it is my Mom!) Right above every single light bulb on the bar light above her mirror, there were black soot stains.
    I'd be willing to bet these people either love their candles, run a gas fireplace alot, or are smokers. Hope this helps..........


  8. #8
    Wayne Falcone Guest

    Default Re: Residue on wall above baseboard heaters

    The candles do produce a lot of soot, however if you keep the wick trimmed down low it will eliminate most of the soot. Also the warm soot will be drawn to the colder areas of the house. (wall studs, ceiling joists, high hat lights, etc.)
    I inspected a friend's house who had black soot stains on the walls, ceilings, around the high hat lights in the cathedral ceiling and on the second floor carpeting. She had called in 3 heating contractors and another Home Inspector to check why her heater was causing all the soot. When I walked in the door there were 4 candles burning in the kitchen and 5 in the family room, with the cathedral ceiling. She was also, a concert pianist and every night when she played she would light approx. 8 to 10 liquid oil candles on top of her piano. Throughout the house she had approx. 25 additional candles that she would light from time to time. I told her that she would have to stop burning the candles if she wanted to eliminate the soot. She told me that I didn't even look at the heater yet, how could I determine that the soot was coming from the candles. I explained that I had seem the situation before and had similar stains in my house when my wife was continually lighting candles. When we stopped lighting the candles the soot stains did not return. Then she stated that she had to have her candles, they helped her relax and they made the house smell nice. I told her she will have to learn to live with the stains or paint the walls with dark colors.

    Enjoy life,


  9. #9

    Default Re: Residue on wall above baseboard heaters

    Not really sure where to post this problem. About 4 years ago I noticed that we were getting black lines at the top of our walls that went out across the ceiling. Similar to what you would see if I fire had gone up a wall and what the smoke would leave. My husband always blamed it on my burning candles. One weekend after being gone we came home and it was all over our ceilings. We determined it was a puff back from the furnace. A cleaning company came in, took about 3 weeks and cleaned my house top to bottom, painted everything and we replaced our furnace. Now I'm starting to see this again. Again, he's saying candles burying his head in the sand. But I've found spots on a baseboard, ceilings, on the back of my daughters bedroom door behind a dress she has hanging there, also black going up the wall by a couple electrical outlets. I have pictures but I'm not sure how to post them as I'm new here today. But I know it's not candles because the black would be above candle level and it's both above and below candle level. Can anyone offer any suggestions please? I'm going nuts!! I want to reprint again but if I can't figure out this problem I'll just be wasting time and money reprinting. We have oil heat and its not just one room. It's in most rooms actually. I do not use oil candles and have even bought a couple electric wax melting warmers as to not use candles! Very frustrating. I dont have any idea who to call. Thank you!

  10. #10
    Join Date
    Jan 2007
    Brooklyn, Fire Island

    Default Re: Residue on wall above baseboard heaters

    Quote Originally Posted by Roogie3259 View Post
    I know it's not candles because the black would be above candle level
    That's an odd assumption to make.

    Truth is just one man's explanation for what he thinks he understands. (Walter Mosley)

  11. #11
    Join Date
    Jun 2004
    South San Francisco, CA

    Default Re: Residue on wall above baseboard heaters

    Do an internet search for "ghosting walls".


  12. #12
    Join Date
    Dec 2005

    Default Re: Residue on wall above baseboard heaters

    Yep, it's the candles alright. And probably a faulty oil-fired boiler as well. Get rid of the candles and have the oil burner checked. And listen to the husband once in a while, he's not as dumb as you think.

  13. #13
    Join Date
    Jan 2013

    Default Re: Residue on wall above baseboard heaters

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