Mold on laundry room wall (C) Daniel Friedman What Does Indoor Mold Look Like? Black Mold spores in the Home
How to recognize toxic black mold & other indoor mold in buildings
     

  • MOLD APPEARANCE - WHAT MOLD LOOKS LIKE - CONTENTS: Photos of black mold & other dark colored mold on & in buildings - how to find & recognize mold on building surfaces. Photographs of black and other dark colored mold on drywall, on plywood subfloor, behind wallpaper, and in wall cavities and on building insulation kraft facing paper. Black mold identification is included in this article.
  • POST a QUESTION or READ FAQs about what black mold, "toxic black mold" or plain cosmetic (harmless black mold) looks like in buildings, including homes, offices, and even in boats, cars, trucks, and mobile homes.
  • REFERENCES

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What does building mold look like?

Here is an online reference photo library of various kinds and colors of mold as it is found growing in buildings.

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

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Photographs to Help Identify Mold in Buildings - What mold contamination looks like in a home

Directories of 6 atlases or indices of building mold

Black mold on drywall (C) Daniel Friedman
  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

Identification Photographs of Black Mold in Buildings - what does black mold look like?

Mold on basement laundry room wall - Daniel Friedman 04-11-01

Black mold in the laundry room may look like this extensive case. In cases of large areas of visible mold, unless the mold proves to be only cosmetic mold, professional cleaning is probably needed.

Look closely when inspecting or collecting test samples of "toxic black mold" because often there are other molds, sometimes more harmful and more easily airborne mold species on the same surface, on the hidden side of the same surface of drywall, or nearby.

These include lighter colored genera/species of Aspergillus sp., Penicillium sp. etc. which are too often missed when investigators or building owners focus only on "black mold" testing.

Stachybotrys behind baseboard - Daniel Friedman 04-11-01

Tiny Stachybotrys toxic black mold colony
on drywall behind a laundry room baseboard. If this is all that's present this is a trivial cleanup and does not need testing and remediation.

But if this is a "tip of iceberg" clue of a larger hidden problem in the wall, or if it might be, further investigation, at least exploring the wall cavity, would be appropriate.


 



T Scriptis in rotting subfloor - Daniel Friedman 04-11-01

Black mold on rotting subfloor below a leaky sliding glass door - this "black mold" was Taeoniella rudus for which no medical issues have been reported - a wood rotting organism though.

An investigation of the source of outside leaks and extent of damage to the structure were needed at this building.

Black Stachybotrys chartarum black mold on wallpaper below a leaky window. The window had been left open more than once during rainy weather. We found that water was leaking into the wall cavity, not just behind the wallpaper.

Stachybotrys black mold on wallpaper - Daniel Friedman
04-11-01

Replacement of a small section of drywall, wall cavity insulation, and wallpaper were appropriate at this location where the first symptom was loose peeling wallpaper which exposed black mold.

Memnoniella echinata black mold in wall cav - Daniel Friedman
04-11-01

Toxic black mold, Memnoniella echinata visible at a small test cut into the wall cavity and contaminating fiberglass insulation in a NY City high rise apartment after water leaked from an A/C condensate line into the metal track of the metal-stud wall.

Larger wall cuts to look for hidden mold and final demolition exposed a very extensive toxic mold colony in this building. Lab processing of a tape sample of this mold was necessary to identify it.

Notice the funny black mold growth pattern on the cavity side of the opposing drywall. This pattern maps the points of contact of the wall insulation kraft paper with the drywall surface, and the movement of moisture and spreading mold growth on the wall surface. It is characteristic of wall cavity mold and is different from the growth pattern of mold growing on a freely exposed-to-air drywall surface.

extensive mold hidden in fiberglass insulated wall cavity -
Daniel Friedman 04-11-01

Black and hidden mold in fiberglass wall insulation in a basement exposed to prolonged wet conditions from a wall leak at a water pipe entry point. This mold was almost hidden except for a small mold-suspect patch and larger water stains on the exposed side of the drywall.

The wall cut exposed a surprise point of water entry. Black mold was visible on the insulation kraft paper.

The problematic mold in this case was not visible but was found by a special sampling technique we used to examine the building insulation for Aspergillus sp. and Penicillium sp. (problem molds) in the fiberglass.

It was found to be highly contaminated and was determined to be an active reservoir releasing high levels of airborne mold into the basement.

More Photos & Close ups of Black Mold on Building Surfaces

Black mold on drywall (C) Daniel Friedman Black mold on drywall (C) Daniel Friedman

Our mold photo at above left shows black mold colonies growing among green mold colonies on a laundry room ceiling, covering both plastic ceiling tile material (around the plumbing pipes) and drywall. It is often the case that multiple mold genera/species may be growing in the same area, often on the same surface, and at times, on top of one another.

As we advised earlier, look closely when inspecting or collecting test samples of "toxic black mold" because often there are other molds, sometimes more harmful and more easily airborne mold species on the same surface, on the hidden side of the same surface of drywall, or nearby.

In this building that was still wet at the time we took this photograph, the airborne level of Aspergillus sp. and Penicillium sp. (the green, gray, and light colored molds in the photo) was very high while the level of airborne Stachybotrys chartarum, Cladosporium sphaerospermum, and Nigrospora sp. (black molds found on these surfaces) was very low.

Our photo at above right shows black mold colonies as smaller "spots" growing on the painted surface of cloth covering asbestos pipe insulation.

Black mold on drywall (C) Daniel Friedman Black mold on drywall (C) Daniel Friedman

Our black mold photos above show dense black fungal growth on drywall (black mold on Sheetrock™ type wall surfaces) in areas that have been very wet. The distinct top edge of mold growth may mark a flood water level or a discontinuity in the wall material, such as a tape joint in drywall that affected the moisture gradient in the wall and thus the mold growth pattern.

Close up Photographs of Black Mold on Building Surfaces

Black mold on drywall (C) Daniel Friedman Black mold on drywall (C) Daniel Friedman

Here we begin to "zoom in for a closer look at dense black mold growth on indoor building surfaces in a wet basement. Notice that the mold growth on drywall and often on other surfaces includes a family of circular growth patterns (upper area of photo at above right) until the mold growth has expanded to form a solid black covering (left wall of photo at left and lower wall of black mold in photo at right).

Black mold on drywall (C) Daniel Friedman Black mold on drywall (C) Daniel Friedman

Our photo at above left shows black mold colonies as individual rounded "rings" on the cavity side of drywall on a building crawl area wall. The black mold photo at right shows how dense black mold may be hidden from view behind wall baseboard trim (removed for this picture) in a building that has suffered wet floors.

Black mold on furniture (C) Daniel Friedman Black mold on canvas clothing or bag (C) Daniel Friedman

Black mold growth on furniture is obvious in these two photographs, of a mold on a leatherette surface (left) and on an upholstered chair (right).

Black mold on drywall (C) Daniel Friedman Black mold on drywall (C) Daniel Friedman

In our photo at above left we see black mold and other mold growths on the kraft paper facing of fiberglass building insulation. Our black mold photo at above right shows that mold colonies do not always grow in the neat round ring-like colonies shown in some our earlier photographs.

Black mold on drywall (C) Daniel Friedman Black mold on drywall (C) Daniel Friedman

Here we start to zoom in our photographs of black mold on building surfaces to show what mold colonies look like on close inspection in-situ. At left is mold on water stained drywall in a basement utility area. At right are small mold colonies that have appeared on a kitchen ceiling in just a few days after a heating system leak led to high indoor moisture and humidity levels.

Closeup of Black mold growth on drywall (C) Daniel Friedman Black mold under the microscope (C) Daniel Friedman

Much more closely we can examine an individual black mold colony on a painted drywall ceiling (above left). In the microscope at 1000x we can see individual spores of Stachybotrys chartarum - a well known black mold that is often found on indoor building surfaces.

Other Examples of What Mold Looks Like in Buildings

Question: Is this stuff on my ceiling mold?

Ceiling stains (C) InspectAPedia.com and L.B.I just moved into a rental trailer and it had a strong musty smell. I thought, maybe it hasn't been aired out. well, after two days of doors and windows open, it still smells. I found the brown discoloration on the ceiling in the kitchen cabinets. Is it mold? Thank you, - L.B.

Reply: maybe not, but those water stains mean there may be a significant risk of hidden mold indoors

Your photo shows some heavy staining on what looks like suspended ceiling tiles. The brown stains themselves may not be mold but rather brown materials carried by roof leaks into the ceiling structure. Older trailers and mobile homes often have leaky roofs.

It looks as if water has also run down the wall surface and quite likely the wall cavity of the home below those same stains.

In this case the stains you see might not be mold but they do indicate that there is a high risk of mold in this home. Here are spots where I'd suspect a more hidden but possibly larger problem reservoir of mold when we see leak stains like yours:

  • The ceiling tiles may themselves be moldy on their upper or hidden surface, depending on what they are made-of. Even plastic-faced fiberglass suspended ceiling tiles that might not look moldy may in fact be contaminated if they have been wet.
    See INSULATION MOLD TEST.
  • The back side of wallpaper that has been soaked is often moldy.
    At HIDDEN MOLD in OTHER PLACES we include a photo of mold found behind wallpaper that looked just fine from the room side.
  • If the walls are covered with drywall behind that wallpaper, its cavity side may be moldy, though more likely your walls are paneled. Un-painted cavity side of wood paneling often supports mold growth and of course insulation within the wall cavity may be wet and moldy too.
  • Finally, where we see significant stains at a wall/ceiling juncture indicating a history of roof leaks that sent water into and down the wall, we take a close look at carpeting, carpet padding, and insulation that may be under the floor below.

I suggest having someone take a look at the insulation and floor condition in the area of leakage from below the mobile home. If that area is wet and damaged you can pretty much expect that there is hidden damage and mold in the ceiling and wall above.

If the damage is not so extensive that immediate major repairs to the structure are needed, but if there appears to be anything greater than 30 sq.ft. of moldy material, professional cleaning and repairs are needed. And the cleaning and repair work cannot be concluded before the leaks are fixed.

Watch out: in some mobile homes where there has been chronic leakage we have seen floors that were badly deteriorated and even collapse.

Finally, because you are renting, you will want to see our mold advice for renters: RENTERS & TENANTS: MOLD ADVICE

Continue reading at BLACK MOLD, HARMLESS or select a topic from the More Reading links shown below.

Or see MOLD GROWTH on SURFACES, PHOTOS for an extensive catalog of images of mold growth on various materials & surfaces

Suggested citation for this web page

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

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