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Here we illustrate and explain reddish brown or pale yellow bubbly surfaces on walls, especially masonry walls or on masonry chimneys, caused by leaks & moisture - efflorescence and sometimes creosote leaks. 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. Our photo at page top shows white fluffy crystals of mineral efflorescence near the bottom of a poured concrete foundation wall.

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 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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What is the Brown or Reddish Bubbly Stuff Found on Building Walls?

These two photos of ugly reddish brown and white bubbly "growth" on a wall were sent to us by a reader. This stuff looks like terrible mold but it's probably not mold at all.

We won't know for sure without testing the material or inspecting the building. But it sure looks like reddish-brown salts left behind by water and moisture passing through a masonry wall or a plaster wall, evaporating from the wall surface and leaving behind all of the crud that the moisture picked up from the wall itself as it passed through.

We often find this darker colored wall deposit on older buildings built of brick and stone whose interior wall surface is plaster applied directly to the masonry wall. We also often find this wall "growth" when water has been leaking in a plaster wall cavity. Plaster is so alkaline that it is not as friendly to mold growth - it's not "mold proof" as mold may grow on or in paint or even on or in organic material in or on the plaster.

What is Causing the Bubbling and Peeling of Paint on Foundation Walls?

Take a look at this closeup (above left) of peeling paint on a foundation wall in a basement. The lumpiness of the surface tells us that this wall has been painted a number of times, painting over a rough concrete or concrete block surface.

In the center of the photograph (above left) you can see where paint is falling away and the gray concrete or concrete block is exposed. At the upper left corner especially you can see rounded bubbles of material that looks as if it is "growing" on this foundation wall.

The author's hand (above right) shows a combination of peeling paint, deteriorated masonry surface, and mineral salts all left behind as water and moisture have been passing through the building foundation. There is a water problem in this building and a moisture problem, but the stuff on the wall and in hand is not mold.

These pictures shows combination of peeling paint and yellowish-white mineral salts left behind as water is passing through this wall as moisture or as actual liquid water. The moisture is both pushing paint off of the surface and also leaving behind salts of various minerals that were dissolved out of the wall as the moisture passed through it. When water evaporates from a surface it leaves behind minerals that were dissolved in it.

Diagnosis of White & Brown Stains on Brick or Concrete Block Chimneys

White powdery stuff appearing on a brick chimney may show up indoors or outside (photo above left). Brown stains leaking out of any chimney (photo above right), whether masonry or metal, may indicate a dangerous condition - prompt inspection is needed. We find these stains on concrete block or "cinder block" chimneys as well, and occasionally on stone chimneys.

Brown stains on a chimney wall may also show up indoors or outside (photo above right). The brown stains are probably from creosote or soot washing out of the chimney interior flue and leaking into the attic through the chimney wall. This chimney needs immediate inspection and repair.

In either case we recommend that you promptly hire a professional chimney sweep to inspect the condition of the chimney including at the rooftop and inside the chimney flue. Water leaks into a masonry chimney can damage it and make it unsafe both structurally and with respect to leaking dangerous flue gases or even sparks that could cause a fire.

See CHIMNEY INSPECTION & REPAIR GUIDE for details.

What Does it Mean to Find Efflorescence and Stains in a Building Interior?

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MOLD APPEARANCE - WHAT MOLD LOOKS LIKE
  Black Mold  Brown Mold
  Green Mold  Red Mold
  Yellow Mold  White Mold
  Invisible Mold
  Meruliporia Mold Photographs
  Recognize Cosmetic Mold
  Recognize Harmless Black Mold
  Stuff that is Mistaken for Mold
  White stuff that is not mold
MOLD APPEARANCE - STUFF THAT IS NOT MOLD
  HARMLESS INDOOR PARTICLES
    Basketball Mold Syndrome - BBMS
    Black stains from soot/thermal tracking
    Black stains from animals
    Black cosmetic mold
    Efflorescence & brown deposits
    Efflorescence & white deposits
    House dust
    Pollen
    Sprayed foam insulation
    White stuff that is not mold
    Wood sap
ENVIRONMENTAL HAZARDS GUIDE
AIR POLLUTANTS, COMMON INDOOR
ALLERGEN TESTS for BUILDINGS
ALLERGY TESTS for PEOPLE
ALLERGY TEST ACCURACY
FLOODS IN BUILDINGS-priorities
MOLD INFORMATION CENTER
ACTION GUIDE - WHAT TO DO ABOUT INDOOR MOLD
CLEARANCE INSPECTIONS - MOLD CLEANUP
DO IT YOURSELF MOLD CLEANUP
ENERGY SAVINGS in BUILDINGS
ENERGY SAVINGS PRIORITIES
ENERGY SAVINGS RETROFIT CASE STUDY
ENERGY SAVINGS RETROFIT LEAK SEALING GUIDE
ENERGY SAVINGS RETROFIT OPTIONS
FIND MOLD in BUILDINGS, HOW TO
INDOOR AIR QUALITY & HOUSE TIGHTNESS
INDOOR AIR QUALITY IMPROVEMENT GUIDE
INDOOR AIR QUALITY METHODS COMPARED
LEAD POISONING HAZARDS GUIDE
MOISTURE CONTROL in BUILDINGS
MOLD ACTION GUIDE - WHAT TO DO ABOUT MOLD
MOLD AGE - Old is the Mold?
MOLD APPEARANCE - WHAT MOLD LOOKS LIKE
MOLD APPEARANCE - STUFF THAT IS NOT MOLD
MOLD ATLAS & PARTICLES INDEX
MOLD CLEANUP GUIDE- HOW TO GET RID OF MOLD
MOLD REMEDIATION CLEARANCE INSPECTION
MOLD DETECTION & INSPECTION GUIDE
MOLD EXPERT, WHEN TO HIRE
MOLD INSPECTORS & MOLD TESTERS
MOLD PREVENTION GUIDE
MOLD RELATED ILLNESS GUIDE
MOLD RELATED ILLNESS SYMPTOMS
MOLD TEST KITS
ODORS, Smells, Gases in Buildings-Diagnosis & Cure

Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair

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More Information on Building Diagnostic Inspections and Repairs

• 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. Also, not all "black mold" is toxic - here are examples of harmless black mold .
• 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: 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
• Basketball Mold Syndrome - BBMS- sudden attention to old clues in buildings makes them seem brand new to some observers
• 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

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