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  1. #1
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    Aug 2010
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    BC Canada
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    Default What can cause that dark dots

    this happened on the basement living ceiling mostly along the exterior wall. 16 yrs old 3 stories detached I thought that could be some kind of lights installed before. any idea?

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  2. #2
    Join Date
    Mar 2007
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    Orlando, FL
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    Default Re: What can cause that dark dots

    Quote Originally Posted by Peter Louis View Post
    this happened on the basement living ceiling mostly along the exterior wall. 16 yrs old 3 stories detached I thought that could be some kind of lights installed before. any idea?
    Flash photography can skew photos, so I'm not sure what you're seeing in person. Could be anomalies, could be nothing....

    Dom.


  3. #3
    Join Date
    Nov 2014
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    SC
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    1

    Default Re: What can cause that dark dots

    Quote Originally Posted by Peter Louis View Post
    this happened on the basement living ceiling mostly along the exterior wall. 16 yrs old 3 stories detached I thought that could be some kind of lights installed before. any idea?
    LOVE THESE "what is it"'s


  4. #4
    Join Date
    Mar 2007
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    Santa Rosa, CA
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    3,154

    Default Re: What can cause that dark dots

    Candles?

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  5. #5
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    Aug 2011
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    Bennett (Denver metro), Colorado
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    Default Re: What can cause that dark dots

    Color and near walls suggest wall paint daubed on ceiling but the shape of the blobs suggest other than paint mishap. They don't look like insulation voids that can cause ghosts or shadows. They do look a little like paint "holidays". (wrong sheen) Sample with moisture detector would be my first exam. If there is an attic above, then an inspection there is next. They don't suggest mold or leakage from above, but you never know. If dry and not accessible from above, as a home owner, I'd paint with a stain killer and see if they re-emerge before I start cutting holes.

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  6. #6
    Join Date
    Mar 2007
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    Spring Hill (Nashville), TN
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    Default Re: What can cause that dark dots

    Its where they roll painted the walls and hit the ceiling and then touched up the paint… SWAG!

    Scott Patterson, ACI
    Spring Hill, TN
    www.traceinspections.com

  7. #7
    Join Date
    Feb 2008
    Location
    Caledon, Ontario
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    4,982

    Default Re: What can cause that dark dots

    It looks like bleed through, either a stain from above, (i.e. dead mouse in attic) or drywall was contaminated with oil or some other form of contaminate before being installed, and likely poor priming before painting did not hide it stain.


  8. #8
    Join Date
    Nov 2012
    Location
    Tallahassee, FL
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    36

    Default Re: What can cause that dark dots

    Quote Originally Posted by Scott Patterson View Post
    Its where they roll painted the walls and hit the ceiling and then touched up the paint… SWAG!
    that's my guess from what I can see.......and ceiling are very hard to touch up successfully

    - - - Updated - - -

    Quote Originally Posted by Scott Patterson View Post
    Its where they roll painted the walls and hit the ceiling and then touched up the paint… SWAG!
    that's my guess from what I can see.......and ceiling are very hard to touch up successfully


  9. #9
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    Sep 2008
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    so so, California
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    Default Re: What can cause that dark dots


  10. #10
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    Oct 2010
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    MONTREAL QUEBEC-CANADA
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    Default Re: What can cause that dark dots

    I concur with Marc but will relent to give a full nod to the hypothesis.


    Ghosting hypothesis:
    Looks like candles convection.

    Robert Young's Montreal Home Inspection Services Inc.
    Call (514) 489-1887 or (514) 441-3732
    Our Motto; Putting information where you need it most, "In your hands.”

  11. #11
    Join Date
    Aug 2008
    Location
    Pleasant Hill, Iowa
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    145

    Default Re: What can cause that dark dots

    Yes it can be from candles and is called Ghosting, the real name is Brownian Motion.

    Dan Hagman ACI
    ProSite Home Inspections
    Des Moines, Iowa

  12. #12
    Join Date
    Oct 2010
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    Default Re: What can cause that dark dots

    I do not know if I personally would consider the particles randomly placed.
    With candles, I believe it would be considered a form of man-made pollution and thermal tracing.
    Other forms of ghosting can be linked to thermal bridging, thermal tracking, electrostatic deposition.

    Robert Young's Montreal Home Inspection Services Inc.
    Call (514) 489-1887 or (514) 441-3732
    Our Motto; Putting information where you need it most, "In your hands.”

  13. #13
    Join Date
    Feb 2008
    Location
    Caledon, Ontario
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    Default Re: What can cause that dark dots

    For your info.


    December 21, 2006
    Abstract:

    This digest offers a detailed explanation of the causes of carpet discoloration, particulate deposits on surfaces and "ghosting" of wood stud members on the interior gypsum board surfaces of exterior walls.

    BSD-150: Black Stains on Carpets and Ghosting of Framing | Building Science Corporation


  14. #14
    Join Date
    Oct 2010
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    MONTREAL QUEBEC-CANADA
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    Default Re: What can cause that dark dots

    Ray,
    Good solid description.
    Great articles as well.
    I enjoy the narration and the descriptive narrative: (4) four Deposit Mechanisms.
    I could not conceive it as random molecule displacement, but rather home sciences with laboratory testing/modeling.

    How I interpret the article is, there are 2 mechanisms.
    1: Filter.
    2: (Plate Out.)

    Plate out has (3) roles in the attraction or flow mechanism: (1) Electronic, attraction. (2) Temperature, cold surface. Likely a dew point & convection. (3) Impaction motion.

    Thanks.




    Last edited by ROBERT YOUNG; 01-04-2016 at 06:09 AM.
    Robert Young's Montreal Home Inspection Services Inc.
    Call (514) 489-1887 or (514) 441-3732
    Our Motto; Putting information where you need it most, "In your hands.”

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