Questions & answers on how to recognize mold contamination in buildings:

What does building mold look like? These mold recognition FAQs also include references to an online reference photo library of various kinds and colors of mold as it is found growing in buildings.

Our pictures of mold on building surfaces help you recognize mold in buildings, recognize probably-cosmetic mold, and recognize stuff that is not mold and does not need to be tested.

FAQs on how to Identify Mold in Buildings

6 atlases or indices of building mold

1. MOLD ATLAS & PARTICLES INDEX - A-to-Z Mold Atlas of Indoor Clinical Mold, Pathogens, Allergens & Other Indoor Particles
2. MOLD APPEARANCE - WHAT MOLD LOOKS LIKE - What Does Black or Dark Indoor Mold Look Like? Black Mold spores in the Home - a Photo ID Library. What toxic black mold or other indoor mold looks like in buildings.
3. MOLD GROWTH on SURFACES, PHOTOS - What Does Mold Look Like on Various Materials & Surfaces? An extensive photographic guide to mold as it is found growing on various building materials & surfaces.
   
   Also see MOLD GROWTH on SURFACES, TABLE OF - a Table of Kinds of Mold Growth Found on Building Surfaces, lists mold genera/species most often found on specific building surfaces, materials, or contents
4. MOLD in the PETRI DISH, PHOTOS - Photographs of Mold Growing on Petri Dishes or Mold Culture Plates or Settlement Plates
5. MOLD by MICROSCOPE - Mold spores under the Microscope - a Photo ID Library for detection and identification of toxic or other mold
6. MOLD RELATED ILLNESS SYMPTOMS - Mold Related Illness: Index of Symptoms. Readers should not rely on this document for medical diagnosis and instead should consult with their physician or with a specialist such as a medical toxicologist

The building mold questions and answers found below were posted originally

at MOLD APPEARANCE - WHAT MOLD LOOKS LIKE

Condensation on our windows led to stains - is this mold?

Is this mold? Recently discovered condensation build up around my windows

On 2021-11-20 by Anonymous

by Inspectapedia Com Moderator - window condensate may result in mold

@Anonymous,

In general when I see any dark stains on wood caused by water I believe that technically it's usually mold or fungal damage.

That's not to say that there is a harmful mold reservoir or health hazard. You would need to investigate further in the wall cavity.

 

What do you think this is? In bathroom. Mold?

What do you think this is? In bathroom. Mold? On 2021-10-14 by Kristy -

by inspectapedia.com.moderator (mod)

@Kristy,

We could not see mold in your photo with certainty, though there is some evidence of water damage to what looks like drywall along a tile surface. Sorry but I'm not sure what we're examining. That makes offering a clear answer more-difficult.

Perhaps a sharper, closer, or better-lit photo would let me say that I can recognize mold growth.

Also tell me what the material is: drywall, painted concrete, painted wood, something else: as the mold-friendliness of materials varies.

And tell me: has the building suffered leaks, high humidity, or IAQ complaints?

Please take a look at the following article:

WHAT DOES INDOOR MOLD LOOK LIKE

If you still have questions, please let us know.

 

Is this stuff on bathroom cabinets mold?

My daughter moved into an apartment 10 days ago. We notified the manager that her bathroom cabinet was broken, signs of wood rot and looks and smells like there’s a lot of mold. The supervisor of maintenance and the manager came to my daughters apartment and denied that it was mold. Their excuse was it’s just water damage or water stains not mold. They had someone come in and they sprayed it with something that was in a Clorox cleanup bottle and then came back when nobody was there and painted over some of the spots. Can you please tell
Me what you think this is? On 2021-09-02 by Deadra

by inspectapedia.com.moderator (mod)

@Deadra,

I'm not sure what I'm seeing in that photo, but it looks as if there's been protracted leaking and possibly some rot damage to a cabinet.

If it's moldy, that immediate area is quite small in area;

but of course if water has entered walls or floors or ceiling below there could be a larger, hidden problem

In the article index you'll find information about the futility of using bleach to try to cure a mold problem.

by Deadra

Here’s another picture of under the bathroom sink

by Anonymous

@inspectapedia.com.moderator, Did you look at the other picture ? This is the sink underneath the cabinet where it is broken and rotted out. The above picture is a closer shot facing upwards. I accidentally put the wrong picture the first time.

I’m extremely tired from fighting with the management at my daughters apartment. My daughter cannot even use her room or bathroom due to the musty smell and whenever she’s near her room her throat starts hurting and her nose stuffs up, but as soon as she leaves it starts to clear up.

by inspectapedia.com.moderator (mod)

@Anonymous, Deadra;

yes we looked at both of your photos - a bit blurry, which is why I said I could not be sure exactly what we were seeing therein.

If you smell mold, mold is present - nearby.

That does not, by itself, tell us how large the problem is nor its cause.

Find the mold
Remove it
Fix the cause

For moldy materials that are less than 30 sq.ft. of contiguous mold you do not normally have to hire a mold remediation company.

On 2021-08-23 by jason

i am removing portions of drywall in a bedroom and have found black spots on the backside of the drywall (inside the wall). it is only on the "paper" part of the drywall - peeling it back shows unaffected gypsum

. In addition, if one touches the spots, the spot smears. The spotting is not continuous (and not even from panel to adjoining panel!) but does appear at different heights. should i be replacing the drywall or is this something that can be cleaned?
thanks!

by inspectapedia.com.moderator (mod)

@jason,

Without question I would remove any mold contaminated drywall, which is what yours looks like.

It can't be successfully cleaned and it's just not worth the risk of having to do the job over again later.

You should also look carefully at wood and other exposed surfaces for any visible mold and you should see if you can find a cause of such as a water or moisture source, to be sure that that has been addressed.

Are these paneling stains "black mold"?

Hi, can you say if these areas are affected by black mold?

Thanks, On 2021-08-09 by victor

by inspectapedia.com.moderator (mod)

@victor,

I see water stains but from the photo itself I can't tell you the extent of mold that is present. If there has been water in the wall cavity that's an area that needs to be explored. And don't make the mistake of thinking only black mold is a concern.

by victor

thank you very much! And what about this area?

Victor

by inspectapedia.com.moderator (mod)

@victor,

Definite water - leak - stains on the plywood subfloor and joist; some mold likely. But that white stuff? I can't say from the photo as shown whether we're seeing a white fungus (mold) or some sprayed material.

 

Worried about dark stuff on apartment air vent ductwork - mold? Should I move out?

This is my apt building vent along the metal air duct. There are various large patches/patterns of mold on the hallway ceilings which they painted over yesterday but they left this thick area of black, beige and light green on the metal duct?

I'm thinking with this and ongoing moisture issues from the ac and humidity in the building the issue is not resolved even though they cleaned up other areas. Should I move? On 2021-07-26 by Tracy

by inspectapedia.com.moderator (mod)

@Tracy,

I don't quite understand your question about event along an air duct, but I can say that if the only treatment for mold was to paint over it that's a completely improper approach, doesn't solve the problem, hides it, and can be a health hazard to occupants.

You should make that point to the building management in writing.

From a photo alone I don't think anyone knows enough to say "move out" but if there is a large (more than 30 sqft.) contiguous mold contamination area then it does merit professional cleaning/removal.

On 2021-07-07 by Sarah

My father in law thinks this mold is only on the surface of the paint. The area is not wet. Im unsure if i believe its only surface mold due to discoloration of the wall.

They say its from the air conditioner in the home. But if it keeps coming back after years or repainting the walls doesn't that mean its inside the wall and not just external?

by (mod)

@Sarah,

Returning mold growth sure suggests that the actual cause of mold growth has not been found and fixed. That could be leaks, water, high humidity on the occupied space side of the wall, or it could be from leaks into the all cavity from outside.

Is this wall below grade?

Has anyone inspected the building outside for water sources? Inside?

At this point rather than cleaning and painting over, at the very least I would want to

1. pull the baseboard trim and look behind it for more mold and water leak clues;

2. make a small test cut - sometimes it can be small enough to be covered by the restored baseboard if the baseboard's height is taller than the wall's sill plate (usually the sill is just 1 1/2") - I make a 2x 4" cut to look into the wall cavity and to look on the cavity side of the drywall for mold. Make the cut in the most-suspect area (here from your photo that's close to the corner)

Post a photo of what you find

Is this black stuff under baseboard trim harmful mold?

I found this black looking area under a baseboard (haven't pulled the baseboard off because Im afraid I may stir something up if its there) and its this gap where the floor doesnt meet with the baseboard.

So I can slightly see in there. This area is less than 10 sq feet and I think I need to pull the trim off to get a better look. I am afraid of contaminating the whole room as this is a bedroom.

Any advice for proper containment? There was an old ceiling leak here and we never took off the baseboards, I think it leaked from the wall top to the ceiling down and stayed under the baseboard and on the drywall.

We replaced the roof and the ceiling where it leaked, we didnt see any water running down BEHIND the wall when we had the ceiling open.

There hasn't been a leak for 6 years but I did just find what I think is mold and I think its from the time this happened. - Anonymous by private email 2021/07/01

Answer by inspectapedia.com.moderator (mod) - strategy for checking for mold behind wall/floor baseboard trim

@Anonymous,

Those black marks could certainly be mold - if so then we'd be looking for more signs of building water entry or leaks;

I would use a drywall knife or utility knife to cut any paint sealing the trim boards along the board top and corner, then using a flat bar and wedges to avoid damaging the wall I'd gently loosen and pull away the trim sufficient to see its back side and to see the exposed wall surface.

If I see mold on the trim back and on the drywall behind the trim then at the very least we're going to remove the lower 6" of moldy drywall as well as the trim, replacing those with clean materials after cleaning the exposed wall cavity; on an exterior wall we'd replace any insulation that has been wet or moldy; if necessary continuing up the wall until we've reached a 6-12" margin of clean mold free materials.

If in the course of investigation we find more than 30 sq.ft. of contiguous mold it would be appropriate to stop, cover the area, and hire a professional mold remediator.

Strange stains or marks on wall: is this mold?

Any idea what this is? Is it mold? The pattern is strange. It's in a closet with a bathroom on the other side but no leaks anywhere that I can see. On 2021-04-23 by Brandon

by (mod) -

@Brandon,

I'm close to stumped;

The fact that we see two colours is an argument for mold or mold and yeast; but the pattern is rather odd - as if the surface was swept with something.

IF you can smear away the material with a paper towel and a bit of spray cleaner, it's probably mold or a deposit of something else.

If you're certain there's no chance of moisture inside the wall cavity, try cleaning this off and waiting to see what happens.

Else I'd make a test cut to explore the wall cavity.

Black fuzzy stuff in bathroom: harmful mold?

Thanks for the answer a few years back. Tip of the iceberg. What’s all happening here? My bathtub/shower has been basically standing grey water from the tenants above since last November and now it’s got “fuzz” in it. Did some of the moldy plaster that fell in grow itself a bathtub full of itself? On 2021-03-23 by Lin

by (mod)

@Lin, correct me if I've misunderstood the situation, but it looks as if there is a blocked drain leaving standing water in a shower pan.

If the shower backup remains for some time as a puddle in an un-used shower it'd be no surprise to see both some organic deposits (soap scum, skin cells, hair) and possibly a bit of mold growth and also algae growth in that wet area and around its edges.

by Lin

algae makes a lot of sense. It’s nuts in this building. This is below me. Is this as bad as I think it is? About the size of my face and smells to high Heaven.

by (mod) -

@Lin, that black stuff looks like mold;
What you see may be the indicator of a larger hidden mold reservoir on the other side of the wall covering - the details show a history of significant water entry;

It's worth exploring the wall cavity; and wearing appropriate protective gear to avoid breathing moldy dust or getting it into your eye.

by Lin

Me again, and I’m worried I have the basketball mold syndrome, but every stack in the building is leaking, there are termites and rot nearly everywhere; I take thousands of pics to document, but sometimes my eyes hurt and I’m not mycologists, I Was an opera singer.

by (mod) -

@Lin, those photos are not diagnostic and can simply be common house dust and spiderwebs.

At lower left in the photo I think I see think black material that could be fungalhyphae;

However if you have had Leaks in your building then it is perfectly appropriate to have it inspected for both physical and hidden reservoirs of harmful mold.

See the advice given at MOLD / ENVIRONMENTAL EXPERT, HIRE ? https://inspectapedia.com/sickhouse/IAQ_Investigation.ph

 

Black and other spots and stains on drywall found after walls removed: harmful mold?

Does this look like mold? Is it toxic? My apartment had major water leaks last week and these photo is from behind some of the walls they ripped out. On 2021-02-25 by Grace

by (mod)

Yes your photo does look show mold;

"Toxic" is a bit of a broad term for mold: mold may be allergenic, pathogenic, or "toxic" - each of those can have different medical effects; a more general term is "potentially harmful" or "a potential or serious health hazard" -

adding that the risks are greater for people who are themselves at extra risk, such as

Asthmatics
People with mold allergies
People with compromised immune systems
People suffering from any respiratory illness including those associated with the COVID-19 Coronavirus pandemic
The elderly
Infants

The risk level depends as well on the exposure: the amount of mold present and the duration of exposure, well as the presence or absence of high levels of harmful airborne mold spores or MVOCs (gases emitted by some indoor mold growths).

More than 30 sq.ft. or 1 square meter of contiguous moldy material usually merits professional cleaning:

Remove the mold
Clean the Exposed Surfaces
Find and fix the cause of mold growth

Is this dark stuff in wall and ceiling corners in our London Flat mold ?

My daughter is a college student in London and just moved into a new apartment about a month ago. She’s been experiencing a sore throat and other mild symptoms.

She noticed what looks like mold in the top of her bedroom closet (see attached photo). She said the apartment often feels very damp. She is at the doctors now to see if she has COVID or strep throat. We are worried she could be experiencing illness from mold.

The photo of the mold in her closet looks like a type of black mold. She should probably contact her landlady to fix it? But we want to be better informed first. Any advice would be appreciated. Thank you! On 2021-02-16 by Donna C

by (mod) - yesl, that's mold in a London Flat

Donna

That is certainly mold contamination; it looks as if it is inside of a storage cabinet or closet.

While I have on occasion inspected and then tested environments for very low levels of airborne mold spores that nevertheless caused a reaction in someone who was hyper-sensitive,

in most cases, on viewing your photo and IF that is the only visible mold in your daughter's flat,

then the total area of what we can see is not sufficient to explain a mold-related or mold-exacerbated illness, unless someone put their finger in mold and then rubbed it in their eye or a similar sensitive area.

However given visible mold it's appropriate to inspect the London flat more carefully to form an opinion of the probability that there is a larger, perhaps more-hidden, mold reservoir that needs attention.

I recommend two articles that may help you and your daughter with this mold question:

HIDDEN MOLD, HOW TO FIND

and

MOLD / ENVIRONMENTAL EXPERT, HIRE ? discusses how to decide when it's cost-justified to bring in an actual expert

Meanwhile,

- stop storing anything in that cabinet

- remove the mold from what I take to be a hard wood-product surface using any household cleaner

by Donna C

Thank you for your prompt reply. The photo is actually sideways. If you can see the top of a hanger that is the bottom of the top shelf where the mold is. It is the top left corner inside a larger wardrobe closet. The area where the mold is is drywall.

There is not much space for storage otherwise but she can keep from storing anything on that shelf. Doctor visit was inconclusive, but she is to go back if she feels worse. Given that this mold is in a closet in the bedroom we are concerned that she may be breathing in potentially dangerous mold spores. Should she clean off the mold and then cover that part of the closet with a towel or plastic today until the problem can be addressed. A

re you are inclined to think that she should contact her landlady about having the problem investigated further. Thank you again for any suggestions.

by (mod) -

@Donna C,

Yes, I apologize if my prior remarks were not clear. Small amounts of mold, less than 30 contiguous square feet, can be cleaned off by a handyman or even a homeowner using ordinary household cleaners.

I suggested in my previous remark that in addition to cleaning off the mold you can see, it's worth making sure that that's the only problem in the flat.

 

I'm worried that this cob-web like material is toxic mold

Heres a photo of stuff I'm worried is toxic mold

On 2021-01-29 by ihatetwhite

by (mod) hairy stuff on wall - probably not mold

Hateful:

When I click and enlarge your photo I see what looks like a mix of house dust and hair.

 

Can you identify this black mold or lichens?

We recently discovered what looks to be some sort of mold/moss/lichen in window jambs located in our bedroom, bathrooms and kitchen. Please see attached photo. I would describe it as something that looks like black algae or moss or similar.

We are emailing around to see if a professional can readily identify the type of mold based on this photo. So far we have had no success and so were hoping you may know.

We are obviously very concerned about the health risks this may pose and so were hoping to identify this to understand what we are dealing with.

The exact same thing was found in each of the 4 window jambs in the rooms described above and was previously hidden by a plastic tab that has been removed for the purpose of the photo.

Can you please identify for us what this mold/moss/lichen this is? Is it toxic black mold or some other type of mold? Do you know if this is toxic or dangerous? - Anonymous by private email 2020/12/18

Moderator reply: is it mold? Lichens? Something else?

I'm sorry but I don't recognize the black material in your photo. It looks as if it's the fruiting body of a fungus but I agree it might be a lichens or even something else.

I have asked an expert mycologist if he recognizes this material as a fungus or as something else and will post that reply here.

In any event the total volume of it is itself absolutely trivial and would be removed by normal cleaning methods. Trivial means it's not a measurable health risk.

Watch out: However when you see a fungus growing in a windowsill you need to consider that there may have been a leak into the wall below where there could be a larger and more significant hidden mold reservoir or other water-related damage such as rot or insect attack.

Therefore you need to identify and fix the source of the leak that fed this growth and you should consider making a modest or small exploratory opening to check the wall cavity below for mold or other damage.

Reader follow-up: I think this is plastic, not mold

After some more research, we are now thinking it is not even mold. It seems the previous owners placed some sort of construction material in these window sills.

"Reticulated Polyurethane 10 ppi"

What do you think?

Moderator reply: open plastic materials not useful as building insulation

I wondered if it wasn't organic at all - another reader recently shared a photo of some plastic shards that someone had planted in his attic as "insulation" that we discuss
at

INSULATION IDENTIFICATION GUIDE

(search that page for "shredded plastic insulation" to see details)

It ought to be trivial to look at the material more-closely, pull it apart, and perhaps to send me a sharper close-up photo or two of what you've got.

In my opinion the material in your photos, if it's plastic such as the recycled polyurethane sheets (from Merryweather Inc. for example) is entirely ineffective as an insulation material for use in buildings.

 

White and green mold is not likely to be safe?

Does this mold look like it could be toxic mold? On 2020-12-05 by Ben

by (mod) - few molds found on indoor surfaces that are harmless.

There are very few molds found on indoor surfaces that are completely harmless.

If you use the on page search box to search for COSMETIC MOLD you will find there are two dark colored molds that sometimes come in on framing lumber and that are easily distinguished by their growth patterns.

But light green, gray, white molds like those in your photo are not cosmetic.

Such mold may be allergenic or it may pose more serious pathogenic or toxic hazards depending on the health-vulnerability of building occupants.

When there is or has been active mold growth on a building surface you should treat it as harmful and it should be removed, the surface cleaned, and it's cause corrected.

Mould contamiation behind fiberglass insulation and vapour barrier new construction

Hi, I have fibreglass insulation behind a vapour barrier in my newbuild’s basement [photo above].

The basement has a dehumidifier keeping humidity to 50% or lower, but all around the basement the insulation looks like this now.

Is that mould? On 2020-10-18 by Jon

by (mod) -

I see what looks like a water stain and possibly water and possibly mold.

If I am correct them I recommend that we go to the most suspect or worst looking spot and cut that area open to inspect the wall in that area to find the nature and source of leakage.

If you have fibreglass insulation that is wet then it's going to need to be removed

by Jon

Thanks a lot, Dan! That’s great to hear. I’ll get on top of that ASAP. :)

by (mod) -

That's definitely a water leak stain; the brown may be leaching from some non-fungal source behind that insulation, so merits a closer look:

On further investigation, possible IMO only by removing some of the insulation, you'll want to know where the water is coming from; is it from outside - or from moisture accumulating from air leaking into and trapping condensate behind that vapor barrier.

Wet insulation needs to be removed,

the exposed surfaces inspected for mold, & cleaned,

the cause of leakage fixed

new insulation installed

new vapor barrier installed

If this were my home and if the leaks are traced to an outdoor source I would not re-insulate before having

1. fixed the leak source

2. gone through a full year of seasons to be absolutely confident that there is no more leakage

since otherwise we risk having to do this all over again

by Jon

Thank you for the reply... it’s actually all around the basement, sometimes more severe in some places and like the corner in others.

It’s within the first year, so I’d imagine it’s something that’d be handled by warranty.

I assume that regardless, the fibreglass needs to be redone?

Scattered black spots on concrete wall: Mold?

Hello, I'm trying to determine if the following picture is mold on concrete or some other kind of staining. For context:

I live in a 60 year old house with concrete foundation in Southwestern Ontario.

This photo is in the basement utility room. Previous owner divided the room with a partition wall so there isn't great air circulation without a fan, and the basement is fairly humid. Our dehumidifier wasn't working st the start of the warm weather and in the pandemic I was slow getting around to it.

I noticed that a historical spot of efflorescence in the room was "growing" and that got me moving to get a dehumidifier working in the space again. This area is also home to a cat litter box, so it's subject to higher than normal amounts of dust.

I'd welcome any insight and can also can provide a couple other photos. A white efflorescence streak extends the length of the entire adjacent wall, and I'd be curious for insight on why that area might be subject to increased moisture (a function of the lack of air circulation?) - On 2020-06-21 by Scott

by (mod) - is this black mold on concrete or something else?

It does look like mold but I can't be sure with just the data in your photo;

Indeed mold can grow on concrete, though usually it's actually feeding on organic dust or debris or paint on that surface.

Is there water or high moisture?

Is there mold growth on wood nearby? I think I see light coloured mold on some of th boards at the top of your photo.

What do other surfaces in the same area look-like?

Extensive black staining and hairy stuff on wood framing and subfloor of old building: mold contamination?

Leaky toilet went unnoticed. When I pulled the dry wall from the ceiling (black mold or mildew specks) the rafter adjacent to the sewer pipe had these black spikes growing.

At first I thought it was damage to the wood from construction

(100 yo bldg restored 20 yrs ago)

Maybe abrasion from installation of the sewer and plumbing torch.

And I honestly cant tell if they're splinters off the wood or growth. T

hey look so uniform that I'm worried it might be mold or fungus. On 2020-03-13 by Robert Scott E

by (mod) - mold near leaky toilet

It is very strange looking and doesn't resemble a fungus that I've seen.

But there is so much very dark wood sheathing or subfloor that I suspect that there is mold growth on both framing and other wood surfaces in your photo.

Toilet leak caused black stains on wood floor underside of Florida Home: mold?

Two story 40 year old home in North Florida.This is in the floor above a bedroom closet under a bathroom. Source of water damage was a leaking toilet tank to bowl bolt that went unnoticed for several months.

Dicovered and exposed in May, treated undiluted vinegar spray and box fan twice, without wiping. Has remained exposed (closet ceiling removed and door opened). Is less than 10 sq ft. Looking for Remediation ideas On 2019-08-24 by JimC72

by (mod) -

Jim

That looks like several kinds of mold; you need to

1. be sure that any leaks from above are already fixed

2. probe the wood to find out if it's so rotted that it needs replacement

3. Use any household cleaner to clean the surface - spray and paper towels or rags are ok for a small cleanup area like this - spray, wipe, throw the wipes in the garbage;

4. If there's no actual rot or repair needed, you might optionally spray the surfaces with clear shellac or lacquer to reduce future moisture-uptake, OR you can search InspectApedia.com

for FUNGICIDAL & ODOR SEALANT USE GUIDE for other options.

Thick green-gray moldy stuff growing on underside of kitchencounter

I found this under the kitchen counter where the drawer pulls out.

It smells rank and I thought it was dust bunnies, but it has very uniform round bits.

Anyone? On 2019-08- by Lin

by (mod) -

Lin that's a thick mold contamination, perhaps a species of Aspergillus or Trichoderma (though there are other green moulds common in that location such as Trichoderma).

You should avoid breathing those spores as they can be harmful.

If I were cleaning up this mold, because it's easily airborne, I'd wear a HEPA respirator, eye protection, etc.

and I'd be sure, after cleanup, to thoroughly ventilate the room with fresh air.

Wet the area carefully using a household cleaner, remove the mold, fix the leak that caused it.

DO NOT run a conventional home vacuum cleaner as you'll just increase the airborne mold level.

Smell in/at wall leads to discovery of hidden mold?

Hey guys. I had an AC issue that led to water flowing down a wall and into the crawlspace.

It came to my attention when I started to notice a smell in the wall that I would have associated with algae in a creek.

Even weeks after the leak has been fixed. No one else could smell is and there were no visible signs of mold. I finally cut open the drywall from floor to ceiling and found this growth on the inside surface

It's dark green and very powdery like a fine dust. I've read that black mold has a slime coating on it.

Hoping it's not that, but I'm having trouble finding photos of any mold that look like this. Hoped I could get some help identifying it here. On 2019-08-09 by Tim

by (mod) -

Tim:

Thanks for the question and photo, Tim.

1. No one can for-sure identify your mold from the photo alone, though common molds of that appearance and in that location might be a species of Aspergillus or a Trichoderma - it's greenish so I rule out Stemonitis that otherwise can look like that.


2. Worry about "black mold" is a terrible dis-service done to the public by some writers and reporters. To say that "black mold" is the only or even most-harmful mold in buildings is simply dead wrong. Harmful mold may be of any color or texture.

3. We don't need to know the genera/species of this mold to know what to do: the species won't change the cleanup procedure one bit.

4. You'll need to follow the water, remove all drywall that was ever wet, clean the exposed surfaces, fix the leak, repair the building.

IF the total area of contiguous mold is 30 sqft or more then professional remediation is probably in order.

PS: If I were to guess I'd opt for a species of Trichoderma or a species of Aspergillus in your photo; but the genera/species of mold won't change what action is needed.

Very black stuff on HVAC filters - should I take this mold seriously?

Good afternoon. Found this on the back side of filters in an HVAC outflow vent (ie, hit by cold air coming into the room). I've read here that probably need microscopic examination to identify, but just in case...

I don't see any mold growth in the ducts below this vent grill. How "seriously should I take this? On 2019-09-19 by Bob

by (mod) -

The pattern of light and gray dots looks quite a bit like mold growth.

I'm a little confused: filters on an "outflow" vent? I assume you mean you have filters in your air supply registers - which is a bit odd; usually we filter on the inlet end of the system so as to avoid crudding up the air handler, blower fan, ductwork.

Anyway I would

1. remove and clean the vent grille - any household spray cleaner is fine, then rinse and dry.

2. replace your air filters

3. Take a look at the air handler and blower to see that they're clean

4. Look for an abnormal moisture source: mold likes to grow on organic material - that includes house dust deposits on your registers - but won't grow worth mentioning without moisture

5. Don't waste money testing: knowing the genera/species orf mold won't change the cleanup needed

...

Continue reading at MOLD APPEARANCE - WHAT MOLD LOOKS LIKE - topic home, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• MOLD APPEARANCE - STUFF THAT IS NOT MOLD
• MOLD APPEARANCE on VARIOUS SURFACES photo guide to what mold looks like growing on more than 100 different building surfaces
• MOLD APPEARANCE - WHAT MOLD LOOKS LIKE - what toxic black mold or other indoor mold looks like in buildings.
• MOLD ATLAS & PARTICLES INDEX atlas of building molds and microphotographs of mold samples observed in the laboratory
• MOLD RELATED ILLNESS SYMPTOMS Index of Symptoms

Suggested citation for this web page

MOLD APPEARANCE FAQs at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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INDEX to RELATED ARTICLES: ARTICLE INDEX to MOLD CONTAMINATION & REMEDIATION

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Citations & References

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

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