Causes of stains on ceilings:

This article describes how to identify and diagnose ceiling stains in buildings focusing on the cause of various interior wall and ceiling stains and explains how to recognize thermal tracking, thermal bridging stains, building air leaks, and building insulation defects.

Often these stains are mistaken for toxic indoor mold. We also include a description and photographs of normal dirt or debris deposition that occurs around heating or cooling air supply registers. When investigating a building for a mold problem, you can save mold test costs by learning how to recognize Stuff that is Not Mold or is only Harmless Mold but may be mistaken for more serious contamination.

Diagnostic Guide to Ceiling Stains: Building Air Leaks & Thermal Tracking Marks at Interior Ceilings

Found here: definition of thermal tracking or ghosting stains appearing on building ceilings (or walls): cause, diagnosis, cure and prevention. What causes those long parallel dark stains on building interior ceilings?

Photos & text identify thermal tracking, thermal bridging, air bypass, insulation defects and air movement in buildings. How to recognize poorly insulated building walls or ceilings and how to pinpoint building air leaks.

A photo-guide to common indoor ceiling and wall stains and what they mean. Links to more photos of indoor ceiling or wall stains that are not toxic mold.

[Click to enlarge any image]

Our page top photo shows two common thermal tracking or "ghosting" patterns. The narrow dark stains on the ceiling show the location of ceiling joists, and the wide black sooty stain in the upper left of the photo shows where ceiling insulation is less or has been omitted entirely.

Long, narrow, parallel black or gray ceiling stains in buildings may be due to thermal tracking as we explain here.

Common sources of ceiling stains

Ceiling stains are most often due to one of the following:

• Air leak stains at pot lights or wall/floor gaps -
  
  deposits of house dust or debris on cool or moist areas especially at cathedral ceilings and at floor-wall junctures
  
  See CATHEDRAL CEILING STAINS below on this page
• Air supply register stains
  
  near ceiling or wall heating or air conditioning registers - deposits of house dust or contaminants transported through duct systems
  
  See AIR REGISTER STAINS below on this page
• Animal stains,
  
  usually pets, rubbing against or lying against walls may stain walls but unless you have some meddlesome birds, rarely against ceilings
  
  See PET STAINS & MARKS in BUILDINGS
• Soot staining from various sources,
  
  some indicating urgent dangerous conditions
  
  See SOOT STAINING below on this page
• Thermal tracking or ghosting
  
  (introduced below at CEILING & WALL STREAKS below on this page)
  
  Also see THERMAL TRACKING BRIDGING GHOSTING - home
• Water leaks into the ceiling from roof leaks
  
  or in freezing climates, from ice dam leaks
  
  See ROOF ICE DAM LEAKS
• Water leaks into the ceiling from plumbing leaks
  
  See LEAK TYPES, WATER SUPPLY or DRAIN PIPES
• Water leaks into the ceiling from condensation
  
  dripping off of cold water piping or out of air conditioning ducts or bath fan exhaust ducts
  
  See CONDENSATION or SWEATING PIPES, TANKS
• Water leaks into the ceiling from water entering at a building wall
  
  of a floor or balcony above
  
  See DECK FLASHING

The size, shape, location, pattern of any building stain form important clues in diagnosing its cause. King among the easy-to-diagnose leak patterns is thermal tracking or ghosting as that condition tends to produce regular or pattern stains.

Dark Ceiling or Wall Streak Stains

Definition of thermal tracking or "ghosting": sooty or dark lines or stains appearing in patterns on building ceilings or walls

On the inside of buildings, especially in older homes whose interiors have not been re-painted or cleaned in some time.

Thermal tracking or ghosting stains usually map the location of cooler surfaces such as the locations of ceiling joists, wall studs,or areas of smaller amounts of or completely missing building insulation.

Note those dark "stripes" extending along the ceiling? These ceiling stains probably mark the location of ceiling joists (where the in-room ceiling surface temperature was kept a bit cooler since these locations in the ceiling cavity are occupied by a wood joist rather than by insulation).

Thermal tracking ceiling stains, usually black, gray, or dark brown in color, may appear to follow the lines of ceiling joists (and will typically appear roughly 16-inches on center or 24-inches on center depending on how the building was framed (photo at left).

Sooty or dark smudges or stains appearing near the ceiling

On the inside of building exterior walls or at the ceiling-wall juncture, especially in older homes whose interiors have not been re-painted or cleaned in some time.

Thermal tracking stains may appear at the top of the wall and extend onto the ceiling surface such as shown in this photograph.

Thermal tracking or "soot tracking" (also called thermal bridging or ghosting stains) such as shown in the photograph at the top of this page may be found wherever moisture condenses on cool building surfaces.

Warm moisture-laden air touches the cooler surface of a building wall or ceiling, giving up some of its moisture to the surface as condensation.
Also

see AIR MOVEMENT in BUILDINGS

As air moves through the building, typically up walls and across ceilings, debris in the air, particularly soot such as that left by burning candles (scented candles may be more of an IAQ issue), adheres more to the damp surfaces than to others, leaving black marks or "tracks."

In a conventionally-framed wood structure, wall and ceiling framing is typically on 16" or 24" centers.

The wall or ceiling interior surface will be cooler where the framing is located than will be the spaces which are not touched by framing and which, perhaps, are insulated. So if you see black streaks up the building wall in a regular 16" or 24" pattern, particularly on cooler exterior walls but potentially anywhere, it may be thermal tracking.

How to Diagnose Stain Patterns on Cathedral Ceilings

Cathedral Ceiling Stains:

Alan Carson, a home inspection educator and researcher and principal of Carson Dunlop Associates (Toronto), points out that on cathedral ceilings, where we see dark streaks following exterior studs or roof joists, (on cathedral ceilings very often), this is often associated with condensation on the wall or ceiling surface, and dirt in the air sticking to the condensation.

When the condensation dries, you just have the dirt following the stud or joists lines. In the upper left section of our photograph below you can see stains marking the location of ceiling joists.

Ceiling stains over lights:

Al Carson adds that we also see dirt marks on ceilings above light bulbs from chandeliers or other light fixtures using incandescent bulbs. For example, if there are five candelabra type bulbs on a chandelier, we will often see five dark rings on the ceiling above.

These relate to airborne dirt being thrust against the ceiling as a result of the thermals that are created by the heat of the light bulb.

 

Black rectangular stains on ceilings:

that are about the width between ceiling joists are likely to mark areas where insulation has been reduced or omitted entirely - as you can see in our page top photo.

In a cathedral ceiling in which older recessed lights have been installed, you may see a combination of patterns:

• black rectangular stains 
  
  around the ceiling light (insulation was kept several inches away from the light for fire safety), and
• white rectangular areas of "no stain" 
  
  in sections of ceiling between the recessed lights (where an insulation batt was installed, but spaced away from the lights).

Ceiling stains where insulation has been omitted completely:

 may be very apparent such as this photograph taken in a garage.

The garage ceiling was insulated except along one side where you see the long dark rectangular stain. This side of the garage was also an outside wall. In a damp garage, we might find mold growth on this area.

See GHOSTING DARK RECTANGULAR STAINS: CAUSES for more examples of ceiling stains caused by poor insulation and/or air bypass leaks.

Ceiling & Wall Stains at HVAC Registers

Reader Question: Are these stains around ceiling air supply registers due to thermal tracking?

These interior stain photographs are from my daughter's home in Tulsa, OK - could this indicate thermal tracking? It worries me, but her in-laws say it's just dirt.

She has a special-needs 2 year old who has allergies and frequent bouts of pneumonia.

Reply: No. Here is how to distinguish between thermal tracking stains and dust deposited from the heating or air conditioning ductwork

A competent onsite inspection by an expert usually finds additional clues that help accurately diagnose a problem, in this case perhaps a problem with your heating system, air filters, or maybe dirty ductwork, or perhaps finally, an extra source of dust and debris in the building indoor air.

But the pattern of stains and debris in your photos looks as if it is dust and debris being deposited by air blowing out of HVAC supply registers - this is not thermal tracking. Your stain photo above shows that dirt and debris have been deposited on a textured paint ceiling in a dark fan-shaped pattern radiating out from the air supply register at the top of the wall.

Additional debris stains at either side of and just below that same air register track where air probably leaks out around the register cover edges.

The differences between thermal tracking and indoor dust or stains that are coming from the HVAC system include:

• Thermal tracking stains
  
   generally will appear in stripes on exterior walls and on building ceilings where the cooler surface associated with the wall or ceiling framing cause a slightly higher moisture condensation level in those areas, causing in turn, building dust to adhere more rapidly and at greater levels than elsewhere on those walls or ceilings.
• Ductwork dust and debris stains
  
   tend to be located close to air supply registers and appear in a "fanning out" pattern around the register, on a nearby ceiling, wall, or floor.
  
  In your second stain photo (left) we see that the dirt and debris are visible right on the register grille itself.
• Watch out: Soot stains from unsafe heating equipment -
  
  risk fatal carbon monoxide poisoning or oil burner puffback explosion
  
  See GAS BURNER FLAME & NOISE DEFECTS
  
  See OIL BURNER SOOT & PUFFBACKS
  
  See SOOT HAZARDS in BUILDINGS

So it looks as if your daughter's in-laws are probably quite correct - it's indoor dirt, or more technically, airborne dust and debris being blown out of the air supply registers.

I agree that there can be a relationship between dusty or dirty HVAC systems or the absence of a duct system filter and debris stains on indoor surfaces that show up as thermal tracking.

If debris is being picked up and blown through the duct system, and if we also have conditions that invite thermal tracking (minimal insulation, cooler walls, higher indoor moisture, for example), the dust being delivered by the duct system might indeed become deposited in a thermal tracking pattern - the striped pattern that is described above.

But your photos do not show that characteristic thermal tracking pattern - the stains in your photos are not thermal tracking in your case.

What to do about dust, debris, or dirt stains around indoor air duct supply registers

You might want to start addressing the debris stains in your photos by checking for the presence of an air filter in the duct system; if no filter is installed at all, one is needed. If a filter is already installed it may be dirty and needs to be changed.

Typically air filters in residential warm air heat or air conditioning systems should be changed monthly.

Check the ductwork and air handler for high levels of dust and debris. If necessary the ductwork, and air handler may be cleaned.

Considering that the youngster is reported to have recurrent respiratory illness, ask the pediatrician or pulmonologist about the advisability of improving the indoor air quality by reducing the overall dust levels (housecleaning, getting rid of carpets, improved air filtration, etc.) and about the need to have the building inspected by an expert who might look for evidence of mold, rodents, insects, etc.

Soot Stains from Fireplaces or Heating Equipment

Ceiling stains may be traced to use of fireplaces, even scented candles, but more-important, soot deposits in a building may be caused by improperly-operating heating equipment that may in turn be unsafe.

Reader Question: diagnosing ceiling and wall soot stains after heavy snow and a power outage?

After a major snowstorm last week, and 2 week power outage, i see soot stains on the ceiling and walls, with many soot spots, near a ceiling AC return vent. The AC compressor and air handler are unplugged and not working since the fall, so no air should be moving through the vent. Is it possible that somehow air came out of the vent, carrying with it soot from the AC ducts? - Allan

Reply: possible sources of black staining or "soot staining" during and following a power outage

Allan,

It might be helpful if you'd send me some sharp photos of your stains (use the CONTACT link found on our pages). Without seeing the pattern and knowing nothing else about your home I can only speculate.

Sometimes we "see" a stain for the first time when something makes us notice it, but the stain might not really be new. We need to know the pattern, location, and probable cause of your ceiling and wall stains in order to best suggest a solution to the cause. Some examples that might be related to snow cover and a power outage could be

• Use of a fireplace or woodstove
  
  during a power outage might add soot or smoke particles that deposit on walls or ceilings
• Watch out: Soot produced by a heating system
  
  whose draft was interfered with by snow cover over a too short chimney or blocking combustion air intake - check that your heating equipment is operating safely.
  
  I know, power was off, but at power-back-on a malfunctioning heater can produce soot, potentially dangerous.
• If the stains are really ONLY at ceiling A/C air supply registers
  
  and those ducts and registers are used only for cooling, then yes, there can be air movement in and out of ceiling ducts and registers, by convection, during cold weather even when the A/C system and blower are turned off. We discuss this air movement in and out of ducts in more detail
  
  at DUCT SYSTEM AIR MOVEMENT
• Watch out: soot stains traced to improperly-adjusted gas or oil heating equipment
  
  means that equipment is unsafe, risking a dangerous carbon monoxide hazard that can kill building occupants, or a malfunctioning oil burner risking an oil burner puffback explosion. Turn such equipment off and in cold weather, call for emergency heat service.
  
  See See SOOT HAZARDS in BUILDINGS as well as other gas and oil burner sooting warnings given above on this page

 

...

---

---

ADVERTISEMENT

---

---

Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2023-10-26 by InspectApedia DF (mod) - investigate possible causes of ceiling stains or thermal tracking

@Edits For Me La,

Do take a look at the article I mentioned as it will help you diagnose what may be the cause - things like a leak, inadequate insulation, or ventilation patterns.

After reviewing the list of possibilities there, please let us know if we can help further.

On 2023-10-26 by Edits For Me La

@InspectApedia DF,

On 2023-10-26 by InspectApedia DF (mod)

@Edits For Me La,

Without seeing a photo, my best guess is some sort of thermal tracking. Please see

THERMAL TRACKING: DIAGNOSE INDOOR WALL OR CEILING GHOSTING STAINS
https://inspectapedia.com/interiors/Thermal_Tracking.php

and let us know if that helps or if you have further questions.

On 2023-10-26 by Edits For Me La

I noticed this on my ceiling. it is dry to the touch. Its almost like a shadow or something on the ceiling but I dont think it is a shadow cause I can see it when I take a picture with flash. What could this be?

On 2023-10-26 by InspectApedia Publisher - dark spots on popcorn ceiling look like splash marks or paint contaminants

@SDV

I can't say for sure what is the source of those ceiling stains, but I can say that it does not look like the cause is from leaks from above. To my eye it looks more as if something was splashed on to the ceiling or there were contaminants in the textured "popcorn" ceiling paint.

How old is that paint and how old is the building? Depending on age of those, you may want to review the caveats given at

CEILING PAINT TEXTURED / POPCORN ASBESTOS

inspectapedia.com/hazmat/Asbestos_Ceiling_Paint.php

On 2023-10-26 by RE-posted from private email

Hi I had a major surgery last week and have been at home since. Today I needed to use the flash from my phone to stand up and noticed a lot of stains on my ceiling. It’s hard to tell without flash because I have a popcorn ceiling.

I found your page and was hoping you could help me figure out what is happening to my apartment. I tried commenting on the box but couldn’t upload my pictures.

Thanks in advance for your help. - SDV

...

On 2023-09-29 by InspectApedia Publisher

@Helen,

I can't see enough to be completely confident but I think I see what might be leak stains. If that's so it'll be appropriate for you to ask your school to investigate for leaks, water damage, and mold on the upper side of those suspended ceiling tiles.

On 2023-09-29 by Helen

Hi! My sons elementary school’s ceilings are full of these black shadows. What can they be? I am worried it’s bad for my sons health.

On 2023-09-24 by InspectApedia Publisher - suggestion of exploring the roof cavity is very important

@Joe,

Metal roof, undamaged, properly-installed, reduces the chances of a leak from above; I look forward to seeing that surface.

Also BTW a metal roof passes zero moisture up out of the building and increases the risk of indoor moisture condensation on the roof underside - so my earlier suggestion of exploring the roof cavity is even more important than we knew at first exchange.

On 2023-09-24 by Joe

@InspectApedia Publisher, thank you so much. It is a metal roof that appears to be In good condition. I’ll reply again when I get a better look or more info.

On 2023-09-23 by InspectApedia Publisher - pattern of mold growth suggests high indoor moisture

@Joe,

An on-roof inspection would be appropriate - we don't know what's on the roof nor the condition of the roof covering.

But yes, the pattern of mold growth suggests high indoor moisture.

It would be sensible to remove all of that moldy drywall and then to inspect the condition of the roof sheathing and framing that are thus exposed. Those may need cleaning and insulation there may need replacement.

Post photos of what you find and we can comment further.

Df

On 2023-09-22 by Joe

Looking at a house that’s not been lived in for years but in which one hvac system has been left on. It doesn’t supply to this area with the cathedral ceiling.

I initially assumed this was a simply mold from humidity with no circulation of air. Insight would be greatly appreciated.

On 2023-08-20 by InspectApedia Publisher - "straight" edge ceiling stain may be mapping a line formed by a ceiling joist

@John,

Usually the type of stain in your photo is due to water or at least high moisture. I appreciate that the ceiling may feel dry but still the stains could be caused by moisture - less wet than is obvious to the touch. You could try checking with a moisture meter.

I have also seen light colored bleed-through in a painted ceiling that previously had grease and oil deposits on the ceiling surface. I once painted a ceiling several times only to have the stain reappear - until I sealed the surfaces first with a lacquer primer sealer.

Keep in mind that you don't have to have an actual plumbing leak for bleed-through stains to occur. High moisture from below, absorbed into the ceiling can do the trick.

A "straight" edge along a ceiling stain may be mapping a line formed by a ceiling joist above where it abuts the upper surface of the ceiling drywall - interrupting or reducing the flow of water or moisture.

Are you sure there's no plumbing or leak above?

On 2023-08-20 by John

There's a weird stain that appeared in my kitchen this morning. The ceiling isn't wet or soft and theres no evidence of water in the floor above. Some of the edges are straight. Thanks for your help.

On 2023-08-10 by InspectApedia DF (mod) - thermal tracking perhaps due to uneven distribution of insulation

@Jenny Z,

That looks like thermal tracking which can be caused by any one of several possibilities including uneven distribution of insulation.

Read more here

THERMAL TRACKING
https://inspectapedia.com/interiors/Thermal_Tracking.php

and let us know if that leaves you with additional questions.

On 2023-08-10 by Jenny Z

Hi, I live on the top floor of a building and have had these dark areas in my ceiling for a while now and I 've been ignoring them. They are not shadows, just wonder if they more likely from thermal tracking or roof leak from experienced eyes (this is in CA no snow). Thanks for any input!

On 2023-07-17 by InspectApedia Publisher - water stain near top of cathedral ceiling may be plumbing leak, condensate or other drain leak

@joey,

That's helpful. Then I'd be looking for a plumbing leak, condensate or other drain leak, etc.

We want to be confident that we're not leaving a mold palace inside the wall if there was in fact a wet or water source in that area.

If you can look so closely at the drywall, perhaps making a test cut, to convince yourself that this stain occurred from something that got onto the wall from the room side then you could quit there, though from the photo (indeed a bit blurry) it sure looks like a water stain.

On 2023-07-17 by joey

@InspectApedia Publisher, there is no water or gutter near there, that area from the roof is almost 7ft away when i see thru the attic, only insualtion cushion is around there..

On 2023-07-17 by InspectApedia Publisher

@joey,

That does look as if there may be a roof edge leak or gutter overflow spilling down a soffit and wall, sending a bit of water into the wall top. See if you can inspect that area from the attic, and outside look for signs of leaks or gutter defects.

On 2023-07-17 by joey

i recently spoted this on my catheral celing and not turning on the ac for the last 8months. any idea what is this strip of black spot line on the celing

On 2023-07-15 by InspectApedia Publisher - moldy garage ceiling stain that appeared overnight

@Denny W,

A water stain in a ceiling from a leak from above always, 100% of the time, on the exposed side that you can see, is going to be

- smaller than the total wet area in the ceiling above

- may not be precisely below the leak point (for example water may run along a ceiling joist and appear below where the drywall was penetrated by a nail)

- worth finding and fixing the leak

- worth removing the wet moldy drywall

And please also consider that all colors of indoor mold deserve attention and can be equally harmful, not just "black mold".

MOLD APPEARANCE - WHAT MOLD LOOKS LIKE - what harmful indoor mold looks like in buildings

is worth a look.

On 2023-07-14 by Denny W

The below image shows a garage ceiling stain that appeared overnight. The total stain area is 8 inches by 4 inches.

I live in a multistory town-home with the kitchen sink in the room above the stain and in the approximate vertical area above the stain. I went under the kitchen sink and did not identify any water leak. Using a screwdriver, I poked at the stain. I hit hard wood, except for a quarter-sized hole at the center of the blackest area, where I easily pushed through with my screwdriver. If the stain had been on wallboard, I would have cut out a section to look inside.

A recent infrastructure change was a new heat pump air handler installed in February 2023, on the same level as the garage.

I cannot determine if the stain is:
1. caused by a water leak (by itself),
2. composed of black mold, or
3. a combination of a water leak causing the black (?) mold.

Is my next step to call a plumber or a mold expert?

On 2023-06-26 by InspectApedia Publisher

@Nick A,

I'm sorry but I can't tell much from your photo but those do look like they could be leak stains. It's worth investigating what is above that area.

On 2023-06-25 by Nick A

I found these 2 spots in a top floor bathroom on the opposite corner from the tub (which is only used for baths never showers). The spots are clear and sticky. They are slightly raised and firm. They don’t feel wet at all. Any ideas?

On 2023-06-22 by InspectApedia Publisher

@Carlos,

Take a look at

THERMAL TRACKING BRIDGING GHOSTING - https://inspectapedia.com/interiors/Thermal_Tracking.php

On 2023-06-22 by Carlos

@InspectApedia Editor , our ceiling has the shadow looking marks. We’re on the upper floor of a condo complex. Just not sure what this is and where to look for help.

On 2023-05-31 by InspectApedia Publisher - mold won't come back as an identical stain if cleaned off

@Tim,

It looks more like a bleed-through stain to me. When you clean mold off of a surface and bleach it (not generally needed nor recommended, but I'd be a liar if I didn't admit to having done that), you won't see the identical stain a few hours later.

On 2023-05-31 by Tim

@InspectApedia DF, thanks for the quick reply. I live in Pennsylvania - no rain, ice or humidity in the last few weeks. Above this ceiling is our bedroom, and there is no nearby water source other than the radiators - which I believe are a sealed system.

My question is, is that mold? Bleach removed it… for a few hours, but it came back - exact same pattern. It’s dry to the touch.

It’s an 100 year old plaster ceiling, and the pipes are the same age. Does the pattern / color reveal anything? If possible, I want to avoid having to cut it out. Thanks again.

On 2023-05-30 by InspectApedia DF (mod) - brown spots could be from a roof leak or a condensation problem or another water source

@Tim,

We don’t know from your message if the attic is above this ceiling or if there is another occupied floor above this.

That could be from a roof leak or a condensation problem or another water source. It would make sense to inspect the roof space or attic space above that area or if it's not an attic but rather another occupied floor above then look for plumbing supply or drain piping nearby.

If the attic, inspect for evidence of frost, ice, or leaks or leak stains, and then pull up the insulation over this spot to look at the attic side of the ceiling drywall. Since we don’t know where you are - country, state - we don’t know if ice build-up may be possible.

Discoloration could be caused by water from the melting of ice that may accumulate near the eaves (lower roof edges) if there is a roof ventilation problem and also if heated (moist) air is escaping into the attic from the occupied space.

The risks include mold in that area (starting on the attic side of ceiling drywall) and if water problems become severe, even falling plaster.

So if this is a ceiling below an attic, and if there's attic access, check the ceiling above this area, insulation over that, and roof deck above or near that - for signs of any sort of leaks.

Let us know what you find. Photos are helpful.

On 2023-05-30 by Tim

First, I love this resource. Great job.

We came home from a weekend away and found these brownish spots on our 100 year old plaster ceiling. I removed them completely with a bleach/water solution, but they start to reappear a few hours after cleaning. There has been no rain or water usage at all recently since we were away. The only thing that uses water anywhere near this area is a hot water radiator (which has been off for months). I’m curious if you have any suggestions about the cause.

On 2023-05-06 by InspectApedia Editor - grey spots with hole in the middle on ceilings and walls

@Sandra,

The photo is a bit blurry so when I click to get a closer view I'm a bit lost in the fuzz, but these could be nail pops - take a closer look to see if there is a screw or nail close to the center of each point of damage.

and compare what you see with

and let me know what you think

On 2023-05-06 by Sandra

A few of these grey spots with a hole in the center of some of them have appeared on my hallway ceiling and at the top of the walls. Any idea what they are from?

On 2023-04-14 by InspectApedia Publisher

@Mc,

I'm sorry because we really would like to help but from just that photo which is a bit blurry. I can't tell what the spot is.

If those spots are occurring at widely separated locations I don't suspect a leak.

Thermal tracking discussed above on this page could be the cause.

High indoor moisture could be a contributor.

On 2023-04-14 by Mc

Hi, can you tell me, what these spots are please? They appear randomly on the wall and ceiling. I mean just 1 spot or 2, that's it. It's downstairs and upstairs, and are dry to touch. Thank you

On 2023-04-07 by InspectApedia Editor - raccoons in the attic cause problems

@Seth,

Raccoons in the attic, if there a lot of animal urine in one place, might soak through and stain a ceiling. Please try again with your photos.

Be sure to read about Raccoon Latrines at https://inspectapedia.com/interiors/Raccoon-Latrine-Cleanup.pdf

also see RACCOONS in the ATTIC

On 2023-04-06 by Seth

@InspectApedia Publisher, I did, I sent a picture but I have sense crawled into the crawl space and found out what it is, their is a nest thaat is either a Raccoon or a cat, alsoo found a doll up their that it had dragged in.

On 2023-04-06 by InspectApedia Publisher

@Seth,

Try using the Add Image button below the Comment Box - you can most image types like .jpg .jpeg .bmp .gif but not PDFs nor videos nor documents

On 2023-04-06 by InspectApedia Editor

@Seth,

Of course you are welcome to post questions, comments, suggestions, photos (one per comment) at InspectApedia - we're here to help. Because some questions involve life-safety or the possibility of significant costs, we also promise that all of our website articles and replies to reader questions are made by a live human expert - eg. Daniel F. or Amy C.

We might have a useful guess at what those ceiling stains mean if we could see a photo.

You might also want to take a look in the attic, if it's accessible for you. Go to the area over the stains and carefully lift insulation so that you can see the attic side of the ceiling drywall.

If the attic side is clean - no stains, spills, animals, etc., then the stains you see are coming from the interior of the occupied space - a useful diagnostic step.

Let's see some photos.

On 2023-04-06 by Seth

Hello I found this forum via a goggle search, so sorry if I am not supposed to post. I hae two leaks that hav just appeared overnight. They are small and circular in size. Their is no plumbing or water in the area above the ceiling just crawl space. I haven't been in the crawl space to check it out yet, but I have listened for animals and haven't heard anything an inspecting the outside of the house for entries. The roof is only 4 years old. Anythoughts on what this might be.

Thanks in advance for your help.
Seth

On 2023-02-13 by InspectApedia Editor - toilet cistern was leaking onto the bathroom floor

@AnonYorkshire,

Glad you found the source. Keep in mind that once you've fixed that leak, you'll need to address any damage it caused.

Depending on how long the leak was occurring, the risk for wet interior cavities (ceiling, walls) between the floors increases and also the potential for hidden mold development.

See our initial steps for addressing this potential here:

HOW TO DRY & RESTORE CEILINGS & WALLS

Let us know what you find.

On 2023-02-13 by AnonYorkshire

@InspectApedia Editor , thank you. Turns out the toilet cistern was leaking onto the bathroom floor. Thanks again.

On 2023-02-12 by InspectApedia Editor - leak is working its way down from above

@AnonYorkshire,

That sure looks like a leak working its way down from above.

If there is no floor above this, can you see that area from the attic side of the ceiling, even lifting insulation if need be to look for any evidence of a leak?

If there is a second floor above that window, look at any windows that may be above it for leaks around the trim, flashing, or trim, in case a leak there has worked its way down to this level.

And because it's right above a window, an exterior wall, look at the outside of your home for missing, damaged, or lifted siding or any openings in that area.

After an initial inspection, take a look at

BUILDING WALL / WINDOW LEAK REPAIR

You don't tell us where you're located, city and country, so we don't know if you're in a freezing climate where there's a potential for roof ice dam leaks. Above in this article, we give the live link for more on that topic.

Also above on this page, we list common sources of ceiling stains with live links to those relevant topics that may be of help. Without more information, we can't speculate further.

Please let us know if you have additional questions.

On 2023-02-12 by AnonYorkshire

Hello, please can you diagnose this? Appeared only recently in the Winter? Kind regards.

On 2023-01-13 by InspectApedia Publisher

@Theresa,

I'm glad to help. (Beats a chat-bot I hope).

Do let us know what happens as you go forward with this, as that will help other readers.

Daniel

On 2023-01-13 by Theresa

@InspectApedia Publisher, Thank you. You have been very helpful and I appreciate it.

On 2023-01-13 by InspectApedia Publisher - Discoloration could be caused by water from the melting of ice that may accumulate near the eaves

@Theresa,

Discoloration could be caused by water from the melting of ice that may accumulate near the eaves (lower roof edges) if there is a roof ventilation problem and also if heated (moist) air is escaping into the attic from the occupied space.

The risks. include mold in that area (starting on the attic side of ceiling drywall) and if water problems become severe, even falling drywall. I don't see that from just small areas of staining but it is worth calling this to the attention of your building management, with the advice that they check the attic space for ice and water and thus for water damage and mold. Pay special attention to the (hard to get-to) eaves area.

On 2023-01-13 by Theresa

@InspectApedia Publisher, I think that is what’s happening. I live on top floor of building. This all started after extremely cold temperatures outside for days. ( 30 below.. Minnesota). I am also seeing small discoloration happening in other places (all by the edge of ceiling) Could this be caused by poor insulation above ceiling or ventilation?

On 2023-01-11 by InspectApedia Publisher - shadow caused by loose or dislocated plaster on a ceiling

@Theresa,

That looks to me like a shadow caused by loose or dislocated plaster on a ceiling.

Watch out: for falling plaster. You might press on it GENTLY to see if it moves - if so it's not secured to the ceiling above.

Or if this is drywall then there's some other damage to be examined.

On 2023-01-11 by Theresa

Is this ghosting? It has been checked for moisture and there is none. It started out small along edge the increased in just a couple weeks

Question: cause of sticky clear blistering on ceiling boards

I have searched the internet for a similar image and cannot find what it is.

I noticed this substance that at first glance looked like water drops.

It had been raining ,but the surrounding area was dry as well as the floor and window area directly above.

On inspection the substance felt sticky to touch.

This occurred one other time in a separate room, though on the same type of ceiling and toward the same side facing west.

Hopefully you can help me identify it. - Anonymous by private email 2021/06/15

Moderator reply: Diagnostic questions help identify probable cause oozing blister-spots on a panelboard ceiling

To identify mystery stains on a building surface, a ceiling in this case, some surrounding information can help us make a much smarter guess. Tell me:

1. What are the country and city?
   
   where this building is located?
2. What are the building age and type of construction?
   
   Construction Examples: masonry, wood frame, steel, modular, mobile or manufactured home
3. What are the ceiling materials?
   
   (or wall materials if stains are on walls)
   
   Material Examples: drywall, plaster, wood boards, vinyl paneling, or as I think in your case, a panelboard perhaps made of hardboard with a thin laminated surface of simulated wood
4. What are the locations and patterns of the stain?
   
   Location Examples: in multiple rooms, on top floor ceilings, on lower floor or basement ceilings, in center of ceiling, on ceiling close to an exterior wall, near an exhaust vent or fan, near a heating or air conditioning duct or supply or return register, and on a top floor ceiling, near the center of the building under a ridge or closer to exterior walls?
5. Are there likely stain source candidates other than leaks and air movement?
   
   From the list at the start of this page CEILING STAIN DIAGNOSIS what stain source candidates can you identify (
   
   Examples: heating system soot, history of building leaks, single building leak or storm event

Preliminary OPINION: from just your photo and brief text I am guessing that this is a fiberboard backed faux-wood ceiling paneling, probably using a thin skin of vinyl, paper, plastic or other material to simulate wood in color and pattern.

Notice the large dark area around that stain? That is strongly suggestive of a leak from above.

Explanation: water soaking through a ceiling from above and into ceiling paneling might indeed cause surface blistering, loss of material, and the liquid, when there is or has been recent leakage, may be a mixture of water and other substances leached from the paneling boar or from insulation and other building materials above.

Recommendation: it is important to inspect above these stained areas for leaks or other liquid sources (on rare occasions even animal pets or pests) both inside the roof cavity or attic space and outside by an inspection of the roof surface for leak points.

Watch out for hidden mold contamination, such as on the attic or upper side of ceiling drywall where there have been leaks or accumulated moisture, even from condensation.

And if the ceiling drywall above these dark and blistered paneling areas has been wet, beware of mold contamination on the drywall surface as well as on the hidden or back side of the ceiling paneling.

Details are at HIDDEN MOLD in PANELING from which I excerpted the photo just above, showing me pulling off paneling to expose moldy drywall.

Give us a bit more detail in reply to our questions and let me know what you find in the attic or roof space and we will have further suggestions.

Reader Follow-up: We wiped off the stain, the dark area was just a shadow

My husband wiped it off with a multisurface cleaner.

The dark area is actually shadow. See attached [photo - below]

The interesting thing is when you zoom in on the area. It looks like water drops at first, but not wet. Just sticky.

Thought it might be eggs from some kind of insect, but couldn't find anything.

Anyway, it's gone. Just like the other time. Weird!
Thanks for responding

Moderator reply:

Thanks for that feedback - most helpful and one more example of the hazards of making a diagnostic guess from afar with little information.

Reader Question: are these dark ceiling stains probably due to thermal tracking?

Does this look like "thermal tracking" to you? Here are some pictures of our ceilings on the exterior walls of the house.

North and south sides both (straight rancher. Started showing up a few years back 3 or so. Could this be due to the ac dehumidifier pulling moisture out of the house and actually pulling so much that it pulls from the eaves thru the insulation, then through the sheetrock from our attic? - D.C. 1/10/2013

Reply:

A competent onsite inspection by an expert usually finds additional clues that help accurately diagnose the causes of indoor stains, and s/he might find other causes than what we can offer here, such as an ice dam leak problem, an indoor soot source, or other causes.

That said, your photos look like the dark areas might be due to thermal tracking possibly related to inadequate insulation in the ceiling at the house eaves -particularly if all of the stains on ceilings are at / along exterior walls - in two of your photos I could confirm that the stains are at what looks like an exterior wall, but I also see through a window or door what may be an outdoor porch.

Sometimes where a porch roof is attached to an existing building or building roof, the porch roof is at a lower slope than the roof on the main building.

In that case, we may find inadequate ventilation under the roof eaves of the main building along with an accumulation of snow or ice at the point of change in roof pitch. Either or both of those conditions could contribute to moisture or leaks in that area.

In turn, leaks from ice damming or accumulated snow in that area can dampen the ceiling that in turn invites accumulation of dust or soot stains.

Check the insulation in the attic; Also check that you have not had moisture or leaks in those ceiling areas due to ice dam leaks. Keep us posted.

Cures for Thermal Tracking Stains on Ceilings & Walls

Reader Question: can't I just paint over thermal tracking stains to eliminate the problem?

Can I eliminate the stains on my ceilings and walls due to possible thermal tracking staining? Can I just apply two coats of Kilz to correct the problem before I paint? - pistolpete1950@hotmail.com

Reply: a cosmetic cure for thermal tracking should also include identifying and fixing the cause of staining

Pistolpete:

Painting over thermal tracking stains or many other types of stains on a ceiling, using a sealant such as Kilz™ or Bin™ or Enamelac™ (we get good results from) lacquer based primer sealers will make for a cosmetic repair.

But if you don't address the original cause of the stain, such as missing insulation, high interior moisture, sources of dirt or soot, building leaks, etc., then the stains will return.

 

 

...

Continue reading at GHOSTING DARK RECTANGULAR STAINS: CAUSES or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see CEILING STAIN DIAGNOSIS FAQs - questions & answers posted originally at this page

Or see these

Recommended Articles

• GHOSTING DARK RECTANGULAR STAINS: CAUSES
• HEAT LOSS in BUILDINGS
• MOLD APPEARANCE - WHAT MOLD LOOKS LIKE
• STAIN DIAGNOSIS on BUILDING INTERIORS - home, ceilings, walls, floors
• THERMAL TRACKING BRIDGING GHOSTING - home

Suggested citation for this web page

CEILING STAIN DIAGNOSIS at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to BUILDING STAINS

Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia

Ask a Question or Search InspectApedia

Try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.

Note: appearance of your Comment below may be delayed: if your comment contains an image, photograph, web link, or text that looks to the software as if it might be a web link, your posting will appear after it has been approved by a moderator. Apologies for the delay.

Only one image can be added per comment but you can post as many comments, and therefore images, as you like.
You will not receive a notification when a response to your question has been posted.
Please bookmark this page to make it easy for you to check back for our response.
Our Comment Box is provided by Countable Web Productions countable.ca

Citations & References

In addition to any citations in the article above, a full list is available on request.

---

ADVERTISEMENT

---