This article describes indoor stains and deposits that are not building mold or in other examples, harmless cosmetic mold. 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 - save your money.
Because people sometimes send "mold test" samples to our lab that really should not have been collected, much less looked-at, I provide this library of photographs of things that are "not mold" and don't need to be tested. These are substances that you can easily learn to recognize in buildings.
Save your mold test money, and increase the accuracy of your mold contamination inspection or test for toxic or allergenic mold in buildings: review these items to learn recognize non-fungal materials or even possibly harmless cosmetic black mold often mistaken for toxic fungal growth.
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HARMLESS INDOOR PARTICLES - Examples of scary-looking, usually harmless indoor stuff that is sometimes mistaken for mold
For photos of stuff that is indeed mold contamination in buildings, see MOLD APPEARANCE - WHAT MOLD LOOKS LIKE. So many people have called us to look at things that are not mold that I'm offering some photo tips below. Don't hire an environmental consultant if your only concern is the stuff you see here and if there are no health or air quality complaints. Save your money, don't bother testing the things you see below.
Finding "not mold" material in a building does not mean that there is no mold or allergen problem. Even relatively harmless house dust collected on a surface and sent to our lab as a mold screening test can contain a surprising amount of problematic mold spores if the building has a mold problem.
More important for mold testing, right in among an old colony of harmless cosmetic black mold I've on often found hard-to-see Aspergillus sp. or Penicillium sp. mold that grew there much after the original black mold deposit. Judgment and common sense are needed. Nonetheless, the examples below are unambiguous and should not be sampled for mold testing.
Review This List & These Photographs of Stains or Stuff in Buildings that Are Not Mold or Are Harmless Cosmetic Indoor Mold
In this article on things that are not mold, do not require mold testing, but which may still help diagnose building conditions and history, we'll discuss, describe, and provide photographs of some common items that are sometimes mistaken for mold in buildings:
What about white fluffy "growth" or stuff on walls, particularly masonry walls? You may be looking at efflorescence - which is not mold.
What about brown or even reddish or darker bubbly stuff that seems to be "growing" on masonry or plaster walls? You may be looking at efflorescence - which is not mold.
Be sure to go to Efflorescence & white or brown deposits to review our photos and text on how to recognize mineral efflorescence that is likely to be found on concrete block, stone, brick walls, foundations, and chimneys.
This white fluffy material is efflorescence, a crystalline mineral salt left behind as moisture comes through the wall and evaporates into the building interior.
Brownish or reddish bubbly efflorescence and dirt deposits on walls may be a mix of mineral efflorescence and other salts and debris left behind as water or moisture pass through building ceilings or walls.
Efflorescence is not mold, though it is an indicator of wet conditions that could contribute to a mold problem somewhere in the building.
In sum, although efflorescence is not mold, it often indicates wet conditions that cause problem mold growth elsewhere in the same building. You'll need to identify the sources of moisture or leaks and correct them, and depending on other building air quality complaints or health concerns it may be appropriate to inspect and screen the building for problem mold or other moisture or water-related problems.
What about those clear or opaque spherical brown blobs we see on rafters in attics? Is that toxic brown mold? Probably not. Take a look at this photograph.
Wood sap on rafters in a hot attic forms hard shiny brown or tan spheres that some people think is mold.
It's not. Here's a closer look at sap.
This is not mold, it's sap crystals that have been extruded from the wood due to high attic temperatures. We see more of this sap staining when the wood used for framing was not kiln dried before construction.
Some mold-suspect material in buildings is easily determined to be spray foam insulation.
For more information about foam spray insulation such as Icynene foam, see How to Identify Icynene Foam Insulation and
for an older foam insulating product see How to Identify UFFI Foam Insulation.
To compare actual mold growth with crawlspace foam insulation see this photograph of yellow mold growth taken from a rotting wood truss in a wet crawl space.
You'll see it looks a bit like the sprayed foam insulation shown on this page. But actual yellow mold growth on wood won't be found in a continuous blanket such as shown in our photograph of icynene foam on this page.
See INSULATION INSPECTION & IMPROVEMENT for details about foam and other building insulation types;
see FIBERGLASS HAZARDS for a discussion of mold problems in fiberglass insulation;
see Mold On Foam Insulation for a discussion of when and why we find mold growth on foam insulating materials like foam board and air handler foam insulating board.
As air moves through the building, typically up walls and across ceilings, debris in the air, particularly soot such as that left by burning scented candles, 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 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.
If you have frequent fireplace fires, cooking, or if you burn scented candles, if people smoke in your home, or if your oil-fired or gas-fired heating system is not working properly, the added soot particle load in the building air is not only a health concern (soot and potentially lead), it also will mark the building surfaces in this characteristic pattern.
See our complete article on Thermal tracking or soot tracking .
Basketball Mold Syndrome (BBMS): How Old, Pre-Existing Building Conditions Can Be Perceived as Brand New and Threatening
BBMS is a term we coined for the phenomenon which describes an observer who is certain that a condition s/he has recently seen is a new condition even though solid forensic evidence shows that the condition is long-standing.
BBMS occurs when a person who has (other) reasons to be anxious about health or structural or safety conditions in a building (or any other condition where BBMS may apply) observes some mark, material, or substance for the first time. In other words, the condition or clue, mark, or substance was there before, but the person had no reason to attend, recognize, and consider it.
What Conditions Lead to BasketBall Mold Syndrome?
BBMS occurs most often (in our experience) where health concerns are present and people have become worried about mold contamination, or where structural concerns are present and people have become worried about cracks, stains, or possible indications of building damage.
Basketball print mold: A client was certain that a large collection of round black speckled marks on his garage ceiling were toxic mold, that the marks were growing in size, and that they had not been there when he purchased the home a few years before.
During a mold investigation we had seen and rapidly discounted the significance of these marks, preferring to follow water leaks and moisture to an actual building problem. To an experienced eye it was immediately obvious that the marks had been made by a basketball which someone had bounced against walls and ceilings.
It is important to realize that a stain or mark may have been in place but un-noticed for a long time on a building surface.
In its form of black on white on the garage ceiling the stain pattern was a bit hard to see. We used this trick of reversing black and white in the lab computer, making the basketball characteristic surface pattern of the ceiling marks which we sampled quite obvious.
We explain why this confusion about building clues and mold risk happens in a separate page: please see BASKETBALL MOLD SYNDROME - BBMS
With a little thought we can easily distinguish pet stains on drywall from thermal tracking by the stain pattern and location as well as other details such as the absence of a heat source, or the identification of a location where we'd expect a pet to rest.
Similarly we can identify black stains on walls where people's heads rested while sitting on furniture or in bed (see photo link just below).
Black marks on interior walls such as the black "mold suspect stains" shown on the white painted drywall in this photo might be just be where the dog lay on the floor against the wall (stain at floor level in this picture) or in this photograph of black stains higher on a wall where people rested their heads in bed.
Killer House Dust from an HVAC system which turned out to be cotton and other carpet fibers having nothing to do with the Heating or Cooling equipment was discussed at our Fear of Mold WebLog or "Blog" where we periodically post results of interesting forensic investigations.
House dust might be a contributor to building air quality complaints IF the dust has high levels of problem particles such as mold, dust mite fecals, pollen, sub-micron particulate debris, bacterial contaminants, pet hair, mouse dander or fecal dust, and similar particles.
The most common ingredients in house-dust in a healthy home are:
Pollen Allergens: identification, advice including a pollen identification photo library - pollen may be allergenic, but it's not mold and requires a different approach to detection and cleaning indoor spaces.
Some black mold in buildings arrived on the framing lumber and is harmless both to humans and to the building materials on which it is found.
Often a visual inspection for certain clues (discussed below) can make you very confident of when mold appeared on lumber and what sort it probably is.
We discuss how to recognize and what to do about harmless mold, harmless black mold, and cosmetic molds in our article:HARMLESS COSMETIC MOLD
Make sure that the obvious harmless "black mold" you see (such as shown in the photograph at left) is the only mold growth found.
Dark stains on Wood - not mold
We often see this effect on framing lumber that was left uncovered in storage or at the lumber yard.
We may also see reddish-brown to gray oxidized wood surfaces on all sides of rafters in poorly-vented attics that have been very hot.
Characteristic of this wood coloration pattern is that just one side of the lumber - that exposed to sunlight - will be dark in color.
The following Q&A may be an illustration of this wood stain or oxidation question, though without a lab test we couldn't be sure that there was no mold on the treated wood (sometimes a host for fungal growth) or on other wood surfaces in the attic shown here.
Question: are the dark colors on these roof rafters indicative of mold contamination?
Do you think this is a mold problem on our roof rafter. L.P. 1/13/2013
Reply: probably not
A competent onsite inspection by an expert usually finds additional clues that help accurately diagnose a problem. That said, here are some things to consider:
What the heck - it looks as if that roof is framed over a very very long distance with just 2x6's
I can't be sure from just your photos, but from what I see so far one wonders if the roof is under-framed and lacks proper strength (photo above left).
At above right we can see that someone banged in some additional support between existing rafters using what looks like treated lumber. The fact that the dark color is just on one face of some rafters (photo at above left) and does not extend around the corner from the flat side to the rafter edge is NOT characteristic of in-situ mold growth - more like the wood was left outdoors and weather exposed before it was put to use
The fact that the dark color also does not grow over from rafter faces onto roof sheathing is a similar argument against mold growth on these surfaces since the time of construction
Other Interesting Indoor Stains that are (probably) not Mold
They suggest a one time treatment with Boracare which includes a warranty on re-treatment at no cost. The price offered was $1000. Apparently they have a standard $1500 treatment charge for a basement (no partial treatment) and they warrant the work for as long as one owns the house. They are reputable firm and have been in business since 1992.
The basement is roughly a 3000 sq. ft. walkout and about 60% is exposed beams in separate rooms. One room which is always closed with no windows has no fungus. The edges of the 2x12 beams and some of the sides have white rot. Some spots have a darker brown fungus or almost black. The remaining 40% of the basement has either drop ceiling tiles or drywall (about 50/50).
My question is whether this is worth treating. The house was built in 1985 and is in good shape. We intend to move within 3-5 years.
Several photos are attached. The edge of the beam in photos 2& 3 is supposed to be white rot. The first picture is under a bathroom and shows water stains and apparently there is a darker fungus in this area.
Thank you for your review of this for me. - V.M.
V. I found only one photo with your note - it is displayed above.
A competent onsite inspection by an expert usually finds additional clues that help accurately diagnose a problem with leaks and mold. I am left very nervous about your pest company's little jump onto the mold bandwagon with just the evidence at hand, and question further whether or not those folks are really qualified to inspect for or cure a problem mold contamination. My worry stems from
Those gripes expressed, I can't see what I could confirm as mold in your photo;
I see or think I see in your photo (above)
I'd need to know more about the building to have a sound opinion about what your photo means and about whether or or not more extensive or expert inspection (and perhaps testing) would be appropriate.
An expert would consider not only what she/he can see, but also the leak history of the home, its construction materials and details that increase the risk of a hidden problem, the results of occupant interviews (health risks, building-related complaints), and more information in arriving at a reliable assessment.
But by no means is it appropriate nor justified to always hire an expert. At MOLD / ENVIRONMENTAL EXPERT, HIRE ? we offer suggestions that should help decide if further investigation is warranted.
I have a ledge along the outer perimeter of my basement. I saw a brown dangling snake like looking "something" coming out from the finish woodwork of the and the lip covering woodwork appears to be rotting. Is it mold? Is it correctable? - concerned homeowner 5/27/11
Sorry but with just your description I can't even hazard a guess. It could be a root from a nearby plant, or in some cases a fungal growth. Try sending us a photo using the CONTACT link found at the "More Reading" links at the bottom of this article and I'll take another look.
What about Health problem? I have had head aches for a long time please answer this comment. Thank you and God Bless Nancyjane - Nancyjane Harvey 7/27/11
This page alerts readers to stuff in buildings that is sometimes mistaken for harmful mold. But I'd agree that some other non-mold stain sources in buildings could be very serious problem indicators, such as
- evidence of soot leading to discovery of an unsafe heating system
- animal stains in a building where people have animal allergies
- chemical stains from improper use of chemicals
Details are at the article titled STAIN DIAGNOSIS on BUILDING INTERIORS (link at the "More Reading" links at the bottom of this article )
I have BLack stuff coming out of my air conditions ducks from the ceilings what type of mold could that be. - Dianne 8/17/2011
Dianne, it may or may not be mold - often not.
Search InspectApedia for or click on THERMAL TRACKING Indicates Heat Loss (link at the "More Reading" links at the bottom of this article ) and within those articles on dark indoor stains, see the article titled "Stains HVAC Supply Registers" (or search InspectAPedia on that phrase) to see photos and read text about mold and other black stains around air supply registers and ductwork.
Hi, I have crystalline substance coming out on my Kitchen and bedroom wall (adjoining to kitchen) just above floor. From distant, it appear like white cotton. I remove it in morning and by evening it is again there. Moreover, i am also observing black and pink colored spots on these walls. Is it mold ? It is a new apartment. - Deepak Ladha 8/27/11
I can't identify mold or not from your comment, but "crystalline" doesn't sound like mold to me.
Search InspectAPedia for the article titled Efflorescence & white or brown deposits to read about what you are describing.
We have found two things that we suspect is mold in our rental house. The first is mold coming from between the tiles in the shower, which sprouted slimy gray mushrooms shortly after we moved in.
The second is growths of small clusters of yellow mushroom-like clusters pushing through the painted cinder block in the basement, particularly in one corner of the room. We live in Arizona and do not experience great amounts of rainfall that would cause excess moisture in the basement.
My concern regarding the mold in the shower is that the property manager shrugged it off as something to be remedied with grout. Is that enough, or should the affected area have the tiles removed and any underlying mold removed? The second is that he was scratching the mushroom-type growths from the wall in the basement and pulling off the peeling paint (that is pushing out from darker black spot growths in the same areas) and dropping everything on the floor. If it's mold, doesn't that risk spreading spores through the area? Thanks for any insight you can provide. - Tina 9/26/11
Usually mold growing on bathroom tile grout joints is trivial in quantity and not a health issue; but if you're seeing mushrooms sprouting that suggests that there is a larger hidden problem in the wall, perhaps a wet wall cavity. Same for your basement walls.
Clean up the debris dropped on the floor.
See MOLD EXPERT, WHEN TO HIRE (article link at the "More Reading" links at the bottom of this article ) for help in deciding if further investigation is justified.
I just moved into an apartment and most of the wood windows have a black substance on the bottom trim where the wood meets the glass. In fact, many of the windows no longer have any "finish" left on that part of the window. The apartment is generally filthy from the previous occupant, looks like very little cleaning was ever done while they lived here. Should I be concerned about this "mildew/mold"? - Jeff 10/7/2011
Jeff often we find a small area of mold growth at the inside bottom of windows where condensation keeps the window gasket or frame wet. The total area of mold formed by such areas is trivial and would not explain a health concern, but high indoor humidity and poor building maintenance mean you can't rule out a more significant problem elsewhere.
See MOLD EXPERT, WHEN TO HIRE (article link at the "More Reading" links at the bottom of this article ) for help in deciding if you should go further.
Finally, FYI, there is no mildew in buildings. Mildew is a small subset within the mold family and the two mildew groups grow only on living plants.
I'm searching for answers on a light sandy colored , dust like substance, that appears on the rooftop of the car. Wipe it off and within 12 hours it's back.
only thing above car is the Ceiling and light fittings. Got me completely puzzled. - Alan T 10/15/11
Alan, you'd have to send a sample of the suspect dust to a lab for particle identification, but if you are saying that the material is appearing only when the car is in the garage, I'd look first for trouble with a nearby chimney, flue, or heating appliance. - don't send mold samples to us - it'd be a conflict of interest.
Hey! I've bought a house that was built in 1860, all brick 3 layers deep. The previous owners never tuckpointed, which resulted in me pulling all the brick out because the mortar in the middle of the wall had deteriorated in a few places. In the middle of the brick wall, some of the mortar and brick is covered in a sandy like dark grey substance. Is this a mold that grows on mortar/brick? - Luther 11/3/2011
Luther, I'm not sure what you're seeing inside the brick wall, as there are some molds that will indeed grow on masonry surfaces (as will algae) but more likely you're seeing mineral salts from moisture that entered the wall.
You are describing (I think) a three-wythe thick brick structural brick wall - at intervals, perhaps every 5 courses depending on the wall mason and design, bricks are laid across the three wythes to tie the wall together. Walls of this design expected the outer wythe/layer of brick to act as a rain screen - water that leaked into the wall was expected to run down the wall and exit (perhaps at weep holes) at the wall bottom.
So you wouldn't want to convert the wall to solid brick and mortar masonry during your repairs.
Watch out for bulged, cracked, or broken bond courses in structural brick walls - a serious defect that threatens collapse.
Search InspectAPedia for "Brick Foundation & Brick Wall Defects, Failures, Collapses" to read about these walls.
Hiya there is some white mould on the beading in my attic, its white like snow and as circular pathes of whiter , i cannot see any black in there, iam worried that this is dangerous as my attic as been converted into a badroom and fitted wardrobes, there is nothing in the bedroom part are the wardrobes, but as soon as you go bhind the wardrobes were its the bear brick n roof the mould is growing on all the beading on the roof. its not thick and starts off alot and as it goes up the beading it goes smaller. - Trudy 11/7/11
Could be a fungus, or water leak stains. Take a look at MOLD / ENVIRONMENTAL EXPERT, HIRE ?
We recently finished our basement. The only room that was left unfinished is a "cold storage" room with cinder block walls and a metal ceiling. The room that shares a wall with the cold storage is our office, and is drywalled and insulated. It is also heated centrally with the rest of the house.
The cold storage room is directly under the garage, and is really cold during the winter. We noticed condensation on the metal ceiling during the winter and found mold on a mattress that was stored in there. The room also had a musty smell. We don't have any other soft surfaced things in the cold storage room, and cannot see any other mold on the walls or ceiling.
The mold on the mattress was black, white and tan, and pretty dense. What do we with this space? Needless to say, we pitched the mattress, putting it in a plastic wrapping first. Installing a ventilation fan would require drilling into the foundation of our house which will cost a few thousand dollars that we do not have. Suggestions? - Karen 11/30/11
Karen, once you've removed all mold-friendly materials from the cold storage room you've reduced the propensity for mold growth in that area. What else makes sense?
First make sure there are no foundation leaks sending water into the space. If there are such leaks they need to be corrected.
You may need to install a dehumidifier, a small one that can reduce the humidity without making the space warm. IF you connect the dehumidifier to a drain it can run unattended.
A vent system that flowed sufficient air through the cold room might pick up its moisture and redistribute it through other house areas even as it reduced visible condensation in the cold room itself. Depending on the total amount of moisture and size of the cold room (if it were comparatively tiny) that might be ok but I'm worried you might just be moving a moisture problem from one space to another, and also that your cold room will no longer be cold.
Your cold room might remain adequately "cold" while no longer having a condensation problem if you insulated its surfaces with a moisture-resistant foam board.
Thanks for all of the information. We could care less if the room remains cold, we have been storing overflow storage in there, merely because it offered extra space. We don't have anything in that room that needs to be kept cold. Does this change anything? I was worried insulating would just hide the problem, or give the mold more material to grow in. Can we use the moisture resistant foam board over the metal ceiling surface? Thanks for your help!
Karen: ok; if the room doesn't have to be kept cold, running a dehumidifier, plus the effects of the heat output from the dehumidifier will make an easier time of reducing the condensation problem there.
Insulation does not necessarily hide the problem - I'd oppose that too. But if, for example, you insulate a chilly masonry wall with 1" High-R foil-faced insulation board (covered by drywall if it's an occupied space, for fire safety) then you effectively assure that the wall surface temperature no longer reaches the dew point - condensation on those surfaces stops. You can affix such materials to masonry or metal. Just be sure the metal ceiling is dry before the installation; trapped moisture would mean rust.
what would mold look like on hardwood floors? Barbara - 12/29/11
Barbara, take a look at the photos at MOLD GROWTH ON SURFACES, PHOTOS
Since moving into my apartment a year ago, my possessions are covered daily with a very fine, white powdery substance. It returns almost immediately after cleaning, and finds its way into cabinets, closets, and sealed containers. I think it's killing my electronic equipment, too. (Four items to-date, but the CD player can be sufficiently cleaned so that it works again for a while afterward.)
The carpet was new when I moved in, but the problem is worst in a hardly-used room, despite regular vacuuming. It abated over the summer, but returned with fall and its attendant closed windows and baseboard heater use (which looked clean, but have been partially disassembled and vacuumed). A mold culture was negative. I want a lab test to identify the substance. Do you agree, or have alternative suggestions, please? Thank you, Mary Jo - Mary Jo 1/19/2012
Sounds as if you need to track down an unusual dust source - maybe being distributed by central air or warm air heating. Try sending a dust sample to a forensic lab for help with identifying the dominant particle in your dust - as that may help track down the source. IF the lab says your dust is mostly skin cells and fabric fibers, that's typical for house dust and means you need better housekeeping or better air filtration in your home.
See HOUSE DUST ANALYSIS for some suggestions.
Hi there, we have a strange growth in the bathroom that appears to be coming through the grout between the shower tiles. I started out as a tiny little red spot but over night grew into almost a golf ball sized yellow blob. The yellow blob looked like yellow filler foam or even sticky honeycomb. When we poked at the yellow blob, we noticed that the red colour was still behind it and had grown into a veiny/branchy pattern. Unfortunately I can't send a photo since we poked at it and washed it away before I found your website - but does this sound like anything you recognize? - Michelle Ferguson 1/24/12
Mold growth is common on bath tiles or tile grout; if there is no leak in the wall or ceiling, the proper response is better bathroom cleaning with normal household cleaners, and improved bathroom exhaust venting.
Details about what to do, health concerns (rare) are at BATHROOM MOLD
I get spots on my dry wall ceiling, that wipes off, but comes back within a week. - Molly 2/28/12
If it's mold, look for a leak or moisture source. Just wiping off mold won't prevent its return.
My car windshield was replaced two years ago. Since then, I have noticed that white looking puffy marshmallow mounds have formed on the dashboard air vents. Furthermore, in the years that I owned the car, I was not very savvy about how to wash a car properly and often times would wash down the carpets of the floorboards with a hose (for a few seconds) never allowing for adequate drying. Over the years my grey floorboards turned dark black in patches. My biggest concern are my leather seats, especially on the drivers side.
Again, not being a savvy cleaner, I would use Clorox wipes at times, which eventually ate down the leather to the suade looking material part of the seat. I also developed some tears along the side of the seat and one in the middle of the seat so I placed Clear packing tape over them to prevent further tearing. In a matter of three days, the clear tape turned black and became furry and started spreading outside the sides of the tape.
Eventually after the third replacement, I just extended the tape out, now it covered the tears and some of the exposed worn down leather. Same thing happened. Eventually, I had the whole seat covered and within a week the tape would be black and furry on 60% of the outer edges of the tape. Over the past year, my health has deteriorated whereby I developed chronic fatigue, memory loss, I feel sick after driving in my car for any length, and my back begins to hurt as well. Do you think this could be mold I am dealing with? I am on limited budget so before I hired a remediation specialist I thought I would ask for your expert advice. I appreciate your time in advance. Kindly, Lisa - 3/2/2012
If the problem in your car is recurrent mold growth you won't be successful in stopping it without
Please see our articles on finding, curing, and preventing car mold beginning at CAR MOLD CONTAMINATION
Watch out - be sure to read OZONE for MOLD OR ODORS as well, as some car mold remediators overdo the ozone treatment approach and ruin the car.
Hello, there is a black "stain" at the corner of a smaller room (14' x 12') with concrete walls and a concrete ceiling, located in a humid coastal area. It is at an exterior wall which can get some moisture at times, from rain. There is also a gas cook stove at the diagonal corner of the room, creating steam.
I'm not sure if this black stain is from exterior moisture, or interior cooking of meals. It was painted over, and within about two months, the stain came back through the paint. It is more vertical, at the corner of a wall, from the lower/mid area, on up to the ceiling, with some darker brownish staining on the ceiling surface, at the wall. It is mostly a grayish to blackish kind of color; darker shades in some areas. It does not look wet nor slimy.
Would the toxic form of black mold be like this, on concrete ?
Thank you for any advice!! - Mike 4/25/12
Mike, there are black algae that grow on many masonry surfaces as well as some black or dark fungi; I can't say if your black stain recurrence as a "bleed through" the paint is due to moisture, mold, or simply not using the best paint to seal the surface.
Your description of "thermal tracking" sounds just like what I found on the walls of an apartment. I know there was a flood of water inside, cleaned up @ a month ago. It is now completely dry. Bleach,TSP and scrubbing did not budge the stuff. There is black stuff on the windows, blinds and the worst is behind the fridge looks like dust with soot on it. Can I assume the tenant had some sort of minor fire or could that much soot appear from candles and incense? - Julie 7/26/12
Julie if there was a flood I would look with care at the scope of work done as cleanup and beware of hidden water damage or mold. We do not leave wet drywall in place.
I'm not able to agree with your conclusion but really have too little information to speculate further
our problem is a mold that looks like coffee grounds on the table tops in about 6 inch circles all over the house--cant tell where it comes from--have checked floor vents and ducts..no ceiling vents--what is it and what causes it ? - Jon 8/4/12
Jon, what's bigger than a duck? In other words, lots of things. With 1.5+ million mold species no one can accurately say what mold is growing in your home just by a brief e-text description. A simple tape test sent to a lab can identify the fungus for you = but more likely you should spend your money on finding and fixing the leak or moisture problem that is causing mold growth in the home.
All mold is everywhere all the time - though often at very very low concentrations. It's when conditions are ripe for a particular genera/species to flourish that that mold, or several molds, will begin to grow on a building surface.
Among the things mold needs (most need light, oxygen, something to eat, and moisture), it's moisture that's most under your control.
I own a house in Bavaria Germany, which is 250 years old.
In the entrance hall there are tiles and in between these tiles a white "foam" keeps appearing.
What am I dealing with?
Thanking you in advance.
Gert - 8/16/12
Be sure to go to Efflorescence & white or brown deposits to review our photos and text on how to recognize mineral efflorescence that is likely to be found on masonry structures.
I have noticed a musty smell at my air conditioner air return vent. What could cause this and how do I correct this. Thanks. - Clarence 8/21/2012
Musty smells are often traced to mold contamination; if that's the case, moisture or leaks where they shouldn't be are the underlying problem to be found and fixed. If you see mold or mold-suspect material that is less than 30 sq.ft.. you can use ordinary household cleaners to remove the problem.
Mold removal, not "mold killing" is what's needed.
Watch out not to damage fiberglass duct insulation or liners.
They put up my trusses for the house the other day and I have noticed several areas on them that have green "mildew-ish" areas on them. The trusses were delivered tied up and it rained for off an on for about 4 days before they put them up. Can I wipe/scrub with a mold/mildew mixture? I can get to most of the trusses with use of my ladder but there is a spot or two that I can not reach. If left alone, will this continual to grow or if well ventilated, remain dormant? Please advise on this. Thanks - Green Stuff on Building Material 8/21/12
Sure you can scrub off wood framing materials that are suspect before they are installed in the structure. I can't say from your note if it's mold or something else.
A few square inches of mold-suspect material brought into a dry finished structure won't generally increase the risk of future mold contamination, since what makes building mold contamination grow into a problem is principally moisture (and surfaces of materials that various mold genera/species like to digest, such as paper or wood). And since all mold is everywhere all the time, if your building is leaky, wet, too humid in the future, it will readily be inoculated with airborne mold regardless of the little green stuff you left on the roof trusses.
The hazard that CAN remain from even a small area of mold is that if some fool puts his/her finger into an allergenic, toxic, or pathogenic fungal colony and then sticks that finger into someone's eye, the result might be a nasty fungal infection of the eye. So don't do that.
I have found black spots in my sons room which i have been told is condensation, but now i have noticed there is white fluffy stuff growing on top of this,is this dangerous and what is causing it?thanx - Nadia 8/23/12
What you describe could be mold; I can't say by just your note if it's "dangerous" or not nor what is the exact cause, though if it's mold, the root cause that you can and should address is water leaks or moisture. The "danger" of a mold growth in a building depends on
- the total size of the mold reservoir - not just the mold you see but all mold that is present and whose spores are easily entrained into building air; more than 30 sq.ft. of contiguous mold is enough to merit a professional cleanup
- the sensitivity of individuals in the building; asthmatics, immune impaired, infants, elderly, allergic people etc. are at greater risk
See our article MOLD EXPERT, WHEN TO HIRE for advice in deciding if your problem merits professional investigation or remediation
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