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Discolored cathedral ceiling in stove room

Post in 'DIY and General non-hearth advice' started by John_M, Nov 21, 2012.

  1. John_M

    John_M Minister of Fire

    Joined:
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    Loc:
    Central NY
    Built the house in 2004. R42 kraft paper faced batts in ceiling. Kraft paper toward room side of ceiling. No plastic vapor barrier on ceiling or walls. Two 3' ceiling fans run at low speed 24/7 during the heating season. Soffits are fully open and air has an unobstructed flow up and through the full length ridge vent. Heavy frost on entire roof each sub-freezing morning. No bare spots in the frost. Frost does not evaporate untill sun melts it away. Enitire attic area appears to have excellent ventilation.

    Interior ceiling is painted wallboard. First coat is Benjamin Moore primer (NOT PRIMER /SEALER). This is covered with two coats of Benjamin Moore off-white latex.

    I watched all the work being completed and the various contractors seemed to take great pride in their work.

    This year I have noticed some light gray "shadows" on the ceiling -NOT on the walls. These "shadows" appear to be defining the scissor trusses (16" O.C.) and perhaps some gaps in the insulation. I am unable to climb ladders to the easily accessible attic area which contains a switched 100 watt light.

    My first impulse to remove the "shadows" was to apply a good primer/SEALER over the existing paint and two coats of the existing Benjamin More color on top of the new primer/sealer. This would "hide" the problem. However, if there is a problem with the insulation or vapor barrier I want to fix the problem before re-painting.

    I want to get some feedback from our Hearth members who have experience in this area before I call a contractor.:confused:

    Best wishes, good luck and Happy Thanksgiving to all. :)

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  2. Adios Pantalones

    Adios Pantalones Minister of Fire

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    Did you get up there and see if you can just plain clean it? Could be dust sticks there easier. Is this a room with the wood stove?
  3. John_M

    John_M Minister of Fire

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    Adios, This is the room with the wood stove. I am becoming increasingly convinced that, with age, I am becoming dumber than a post. It never occurred to me that the "problem" could be as simple as dust clinging to the surface. What I failed to mention in the original post is that the ceiling fans running 24/7 blow air "UP" to the ceiling. This would also, as you suggest, blow any ash dust "UP" to the ceiling, allowing it to stick to the various areas. In the next day or so I'll ask a friend to climb a ladder and attempt to remove the "dust" using windex and a soft cloth.

    You and others provide voices of reason to my intellectual wilderness.
  4. Adios Pantalones

    Adios Pantalones Minister of Fire

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    Hope it's as simple as that. We may be at an advantage NOT seeing it, as it's the sort of thing that can trick your eyes (especially aging eyes like mine)
  5. Highbeam

    Highbeam Minister of Fire

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    base of Mt. Rainier on the wet side, WA
    I'm not as smart as adios but I do know that your ceiling has cold and warm spots due to the rafters where insulation can't be. The thermal bridging means that the rafters will always leave cold strips on your ceiling. Your house is modern and from the sounds of it built extremely well. I suspect that there is sufficient moisture in the living area to condense, even slightly, on those cold ceiling strips every once in awhile. Any condensation will create a nice sticky spot for the dust to adhere and with time will become a stripe of darkness.

    Start with a nice cleaning but painting over it will also hide the dust stripes.
  6. John_M

    John_M Minister of Fire

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    Central NY
    Hey Highbeam, :) (and others), Here's one for ya': I have a cast iron kettle on top of the woodstove and the kettle evaporates approximately two gallons of water each 24 hours. Do you believe removing the kettle will eliminate enough moisture to prevent the very slight and spotty condensaton on the ceiling?

    Will removing the evaporating kettle cause other problems? Health problems?

    You mention painting over the stripes: Would a primer/sealer on top of the existing paint prior to repainting help prevent the slight "stickiness" in the future or would application of a primer/sealer be a waste of time and money? :confused:
  7. ironpony

    ironpony Minister of Fire

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    I agree with this observation,
  8. CTguy9230

    CTguy9230 Feeling the Heat

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    we have a room with a higher ceiling, not quite as high as yours by the sounds of it, and we had pretty much the same thing going on..

    got up there with a little cleaner and the dark spots were gone....also i reversed my ceiling fan to blow the hot air down away from the ceiling
  9. John_M

    John_M Minister of Fire

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    CTguy, you are two steps ahead of me: 1) I have not yet made the effort to coerce a friend to help remove the spots but will do so soon; 2) Just yesterday I reversed the ceiling fans to blow "down". As in your case, this should keep most ash dust beneath the ceiling. An unanticipated benefit of blowing the warm air "down" has resulted in much more warm air moving into the bedrooms; the two rooms farthest from the stove. It has taken me three years to discover these little-known secrets.

    Thanks for the tips.

    Good luck and best wishes.
  10. CTguy9230

    CTguy9230 Feeling the Heat

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    no problem...glad i could help

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