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How to Identify Harmless Black Mold on Indoor Surfaces MoldAPedia © Enter your search terms Submit search form   Search This Website - InspectAPedia.com

• Photographs of harmless cosmetic black mold on indoor surfaces
• How to recognize cosmetic or harmless mold indoors
• Links to photos of other indoor materials that are not mold
• Links to photos of harmful indoor mold

When investigating a building for a mold problem, you can save mold test costs by learning how to recognize Harmless Mold but which is often mistaken by some un-trained or inexperienced "mold inspectors" or "mold remediators" as more serious contamination which they call "toxic black mold". Because some clients have on occasion sent samples to our lab that really should not have been collected, much less looked-at, I provide this library of photographs harmless indoor mold and 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." Also see Recognize Cosmetic Mold. © Copyright 2008 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

HARMLESS COSMETIC BLACK MOLD in Buildings

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.

My only caveat is that building materials with cosmetic mold on them can also support growth of other problem mold species if later conditions are right for new mold growth. So inspect "cosmetic" mold growth areas carefully using good lighting techniques.

Make sure that the obvious harmless "black mold" you see (such as shown in the photograph at left) is the only mold growth found.

Cosmetic molds, such as the Ceratocystis sp./Ophistoma sp. group of Ascomycetes are not likely to be harmful to people nor to the wood they're found on. In these photographs of black mold on building framing you can see that the black mold "stops suddenly" at the cut end of a rafter and where a rafter meets the roof sheathing.

"Interrupted" mold growth in this pattern forms unambiguous and compelling evidence that this mold was on the particular rafter at the time of construction. While there are technical exceptions (such as mold growth interruption on drywall at a drywall taping joint), in general, indoor surface growing mold does not stop at an arbitrary "straight line" cut in or on a building material.

Here's another example where a single pre-moldy-2x joist was used to make a built-up basement beam. See this photo of black mold on a built-up wooden girder or beam?

Mold is visible on only one of three 2x12s? This is not live mold growing in the attic nor basement. A microscopic examination confirmed that these surfaces were Ceratocystis/Ophistoma.

More about stuff that looks like scary black toxic mold but is actually something else, something harmless, is at our Mold Information Center

• What to do about Cosmetic Molds on indoor building surfaces: If you are reasonably sure that you’ve got mold like Ceratocystis/Ophistoma that came in on the lumber at time of framing, it’s harmless and also is not likely to grow into a bigger problem. In fact indoors I’ve never found Ceratocystis/Ophistoma mold in an active growth state – I imagine that it needs different (wetter) growing conditions than found in a building. Indoors, even if Ceratocystis/Ophistoma mold was alive, it’s cosmetic-only. Cleaning or removal of a cosmetic mold is entirely optional and would be done (or not) in a building for reasons of appearance, not health.
  
  
• What if I remove "cosmetic" indoor mold and it reappears? If you remove a mold you believe was "cosmetic" and later you find new mold growth in that area:
• the original mold was not a cosmetic genera/species and is one that can grow indoors or
• you have an entirely new fungal growth problem
• you need to remove the new mold growth and you need to identify the reason it formed (a leak or moisture problem) and you need to correct the cause
  
  
• ANY indoor building condition that produces or has produced new or recurrent indoor mold growth on building surfaces means there is also a risk of both visible and hidden problematic molds of genera/species other than just cosmetic molds. Even when you test and identify a specific mold on a building surface you should not assume that the mold you've identified is the only problem, or even the most serious mold problem in the building, unless you have also completed a through, expert diagnostic inspection of the building.
  
  
• To prevent problem indoor mold your focus should  be on watching for and correcting leaks or moisture problems in your building. For details on how to prevent indoor mold growth in buildings see:
  • Building Floods: quick steps after a building flood or plumbing leak can prevent costly mold contamination
  • Mold Action Guide after Flooding: How to Minimize Mold Damage After a Building Flood
  • How to Prevent Mold: how to avoid mold growth in buildings: priorities, repairs, products
  • Humidity Control to Avoid Mold: How Low Should You Keep Indoor Humidity to Avoid a Mold Problem
  • Mold-Resistant Building Practices some detailed suggestions from an expert on preventing mold growth indoors
  • Ozone Warnings - Use of Ozone as a "mold" remedy is ineffective and may be dangerous.
  • Meruliporia incrassata - "Poria" the house eating fungus Meruliporia incrassata or perhaps a different mold, Serpula lacrymans - which one is the "house eating fungus" - what it house rotting mold like in a building and under the microscope
    
    
• In summary about cosmetic indoor mold: If at present you’ve found evidence of mold growth inside of a building other than Ceratocystis/Ophistoma then it’s moisture and leaks that need your attention, not the Ceratocystis/Ophistoma.

Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

WHAT MOLD LOOKS LIKE
MOLD IN HOMES
USING LIGHT TO FIND MOLD
MOLD BY MICROSCOPE
STUFF THAT IS NOT MOLD
HARMLESS INDOOR PARTICLES
HARMLESS BLACK MOLD
THERMAL TRACKING STAINS
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More Information on Finding and Identifying Mold in Buildings and Building Diagnostic Inspections and Repairs

• WHAT MOLD LOOKS LIKE has photographs and descriptions of what real mold looks like inside a building. But be careful, some of the most problematic common indoor molds, the Aspergillus sp. and Penicillium group can be very light in color and hard to see on building surfaces.
• We offer tips on how to look for these hard-to-see molds too.
• STUFF THAT IS NOT MOLD has photographs and description of stains or materials that are often mistaken for indoor mold.
• If you need to see what other indoor allergens look like in a building contact us (information below).

• How to Look For Mold, Hiring a Mold or IAQ Consultant, Getting a Remediation Plan
• Looking for Mold what mold is often found where in buildings - simple technical presentation
• Mold spores in the Home - a Photo ID Library for detection and identification of mold allergens
• Recognizing Allergens: What various indoor allergens look like - identification photos to help identify pollen, dust mites, animal dander, toxic or allergenic mold - Common Mold and other Allergens, Irritants, Remedies & Advice
• Stuff that is not mold but is often mistaken for it - things you may not want to test. We include photos of stains, efflorescence, and other materials that are not indoor mold.
• Harmless Black Indoor Mold not all "black mold" is toxic - here are examples of harmless black mold along with advice about what to do (or not do) about it.
• Animal Allergens: Dog, Cat, and Other Animal Dander - Cleanup & Prevention Information for Asthmatics and regarding Indoor Air Quality.
• Mold in Fiberglass Insulation© 2005 comments about a field study in process, & more about health hazards from fiberglass insulation - DJF
• Mold Investigation Tips for Home Inspectors how to find mold, where to look, what is likely to be important. Advice to building inspectors intending to inspect or test for toxic or problematic mold indoors, mold inspection methods, and mold test methods which are valid or invalid
• Meruliporia: the house eating fungus or "poria"
• Mold Central: indoor air quality investigation case histories, key links what to do about mold and indoor allergens - our Fear of Mold "Mycophobia" WebLog-Blog.
• Ozone Warnings - Use of Ozone as a "mold" remedy is ineffective and may be dangerous.
• Rot concerns in buildings-some building mold such as Meruliporia incrassata "Poria" risks serious rot and hidden structural damage
• Frequently Asked Questions About Mold -- check this FAQ list & IAQ Site Map to see if you can find a quick answer to your mold concern

The Mold Information Center: What to Do About Mold in Buildings, When and How to Inspect for Mold, Clean Up Mold, or Avoid Mold Problems

Use this simple, economical mold test kit by following our instructions on how to collect and mail mold samples to our lab

Environmental Inspection, Testing, & Diagnosis On-Site IAQ, Gas, Air Testing, Mold Investigation, Sick Building Diagnosis, Lab Services, & Remediation Plan Preparation - indoor air quality testing, problem source determination, supporting lab work, written remediation plan addressing removal of environmental and other hazards and prevention of their recurrence.

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