MOLD: To Test or Not To Test ? That Is the Question

Let me start off by saying that I am not a mold specialist, nor do I test for mold.  In fact, home inspectors are not even allowed by the NC Home Inspection Licensure Board to call a substance mold unless they are experts in the field.  We can and do use the words mold-like substances even if it’s obviously mold.  However I did study microbiology in high school and college and my first major was medical lab technician.  I am familiar with mold and other micro-organisms and have worked with them extensively.  Now as a licensed home inspector I work closely with real estate professionals in the transaction of homes.  There is a lot of misconception about mold as it relates to homes and this article is an attempt to clear up the confusion.

My hope is to give you a better understanding of the research on mold; the health effects, what it does to homes and what should be done if it is found.  I hope to clear up questions you might have about how moisture, mildew and mold can complicate home sales.  I hope to give you enough information from the experts so you can understand how unfair the lawsuits are that have been in the news.  To me, the real threat in homes is the long term effects of moisture and mold which is structural issues due to rot. 

From my research as well as my personal opinion, mold testing is not necessary.  When mold, or mold like substances are found in a home by a home inspector, it shouldn’t be a deal breaker even if the inspector/tester thinks it should be.  Let me share with you the conclusions of the experts on the subject so you will have a better understanding of what you are facing when you encounter mold or mold like substances or shall we just call it all – fungus.

Here are the basics about mold:

Molds are decomposers of dead organic material such as leaves, wood and plants.  Without mold, we would find ourselves wading deep in dead plant matter.  And we wouldn’t have cheese and some medicines without mold.  But mold needs water to grow; without water mold cannot grow.  In order to reproduce, molds produce spores, which spread through air, water and by insects.  These spores act like seeds and can form new mold growth if the conditions are right.  Think of spores as dandelion seeds on a microscopic level.  A little air movement and they’re everywhere hoping to land where they can grow.  It’s important to realize that mold spores are present everywhere, in outside air as well as indoor air.  They just don’t grow unless the conditions are right.

Since mold needs moisture to grow, here are a few things to look for around your house.

•    The sprinkler system too close to the house
•    Downspouts and the ground sloping toward the house
•    A watered garden too close to the house

Then there are less obvious sources of moisture in a house you may not see right away that would be picked up during an inspection.  Things like:

•    Moisture movement through exterior walls from things such as:
•    Poor caulking and paint
•    Poor flashings
•    Poor shingles
•    Poor thresholds
•    Interior rooms excluded from air circulation like closets
•    Poor attic ventilation trapping moisture in the attic
•    Humid summer air condensing on cooler crawl space surfaces when there is no vapor barrier present
•    Moisture wicking up through the slab if the builder didn’t provide a vapor barrier
•    High humidity from showering, cooking, etc.
•    Plumbing leaks
•    Any break in the synthetic stucco envelope

Think about this.  It only takes 24 to 48 hours for mold to develop.  How often do today’s homeowners check their crawl space and attic to make sure there are no leaks?  Some areas where mold develops, like a broken pipe in a wall or ceiling, are more obvious and are picked up early enough to make repairs before there’s much damage.  Others like faulty bathroom caulk which allows moisture into the structure over a long period of time, can be so hidden that no one notices until the framing is so rotted the tub falls into the crawl space.  Well, maybe not.  The likelihood of catching mold before it causes structural damage is less likely than finding rot.  We need to be more concerned about rot and structural issues than mold.  Mold can be cleaned up but rot must be replaced and can cause significantly more damage.  Short term moisture – mold, long term moisture – rot.

Construction methods and building standards have changed to accommodate the increased interest in conserving energy.  Houses built prior to the 1930′s generally had no effective insulation in either ceilings or walls.  In essence they were naturally ventilated and moisture dried out quickly.  Roofs were usually steeply pitched and constructed with shingles that had gaps between them which ventilated attics and cooled the roof deck.  These homes were, of course, heat wasters.  Heat escaped into the attics and natural ventilation kept the attic air moving.  Homes today don’t dry out as quickly because we insulate better and build tighter.  Besides that homes today are built with more moisture-sensitive materials.  Paper, like that which is found on drywall is nature’s most perfect mold food.  Mold likes processed wood more than it likes lumber.  Just a little moisture in processed wood like OSB and particle board can affect its stability.

Mold can even be built into new homes.  In this age when time is money, contractors may not wait until the house structure dries out after a rain before sealing in the walls, trapping the moisture in the walls.  This may not happen often but it can happen; so even new homes should be inspected.  If you walk into a brand new house and it smells musty, there’s probably a problem.

Now let’s see what the experts say about mold.

Most people have no reaction when exposed to molds.  The biggest health problem from exposure to mold is allergy and asthma in susceptible people.  However exposure to environmental factors other than mold in damp indoor spaces, notably house dust mites, viruses, tobacco smoke, and cockroaches, along with pesticides, volatile organic compounds and fumes from furnishings or construction materials can cause the same health effects.  There are no tests to determine whether the symptoms are caused by the mold or something else.

There are more than 100,000 types of mold.  Some molds, like Stachybotrys, produce toxic substances called mycotoxins.  These molds generally have a higher water requirement than common household molds and tend to thrive only under conditions of chronic and severe water damage.  Presently we don’t know all that much about the health effects of most mycotoxins on humans.  Most of what we know about mycotoxins comes from exposure of farm animals to moldy grain or hay.  We don’t have any tests that can determine whether mycotoxins are the cause of someone’s illness.  We can’t easily or reliably measure the level of mycotoxins in air samples to determine exposure levels.  Currently there are only guidelines and no regulations regarding indoor mold.  There may never be any regulations on exposure to mold, because even the lowest levels bother people with severe hypersensitivity.  Believe it or not, allergic responses can come from exposure to dead as well as to living mold spores.  Therefore, killing mold with bleach and or other disinfectants may not prevent allergic responses.

What about black mold?  Stachybotrys is a mycotoxin producing mold and usually associated with black mold.  It’s one of several that are very unhealthy but gets all the attention.  Stachybotrys does not easily grow indoors and requires large amounts of moisture to grow.  The known health effects from exposure to Stachybotrys are similar to other common molds, but have been inconclusively associated with more severe health effects in some people.  Testing for it is expensive; the results are difficult to interpret and often inconclusive.

From a 2004 report by the Institute of Medicine:

There are no existing effective, reliable measurement processes for mold and that such assessment techniques should be developed.  The entire process of fungal-spore aerosolization, transport, deposition, re-suspension, and tracking, all of which determine inhalation exposure, is poorly understood, and methods for assessing human exposure to fungal agents are poorly developed.  In clinical medical practice, there is no known dose-response relationship between a specific ambient fungal concentration and any human health effects.  There is no significant clinical evidence that humans have adverse effects of immunotoxic, neurologic, respiratory or dermal responses after exposure to mold other than allergic reaction and that, in the clinical medical field, there is no known dose response relationship between a specific ambient fungal concentration and any toxic human health effect.  Therefore, there is no valid data available to support sampling since an assessment of risk-relevant exposure cannot be produced.

The following are statements from the Scientific Community:

•    The Texas Medical Association’s Council on Scientific Affairs released a report in September 2002 stating that there is no significant evidence connecting “black mold” to human disease.
•    The American Academy of Otolaryngology – Head and Neck Surgery has reported that there is no convincing evidence of a causal association between the black mold Stachybotrys and human disease.
•    The American College of Occupational and Environmental Medicine states that, except for persons with severely