Emmanuel Dec/ 29/ 2010 | 0

Over the years mold issues have blossomed, especially in Texas, with “Black Mold” scares and mold finds in home inspections.  But what are the real effects and importance of mold?

[tab: The Good, Bad, and Ugly]

Mold is an organism that belongs to its own kingdom called “Fungi” (fungus).  The fungi kingdom are neither animal nor plant, and occur naturally in our environment.  Mold spores are present all around us both outside and inside of the home, and are unnoticed due to their very small size.  Mold needs three important factors to survive; moisture, a food in the form of organic materials such as paper, wood, cellulose, as well as other materials, and the last is oxygen.  Mold spores can be found on all surfaces and floating freely in the air around us.  However when the three necessary conditions are available they grow, reproduce, and flourish into the larger, visible colonies that concern us so.

Most people think of mold as a nasty little annoyance or problem.  But mold itself is an essential element of our ecological system.  Mold is one of the many organisms that help to decompose other dead organic matter such as trees, leaves, etc.  Once these organic matters are decomposed they return nutrients to the soil around them.  But for all of the good that mold can do it also has negative effects when located in the indoor environment of our homes.  Mold’s decomposing ability can also damage building materials such as wood framing, sheetrock (drywall), wallpaper, natural fabrics,  and other organic building materials.  If you recall the requirements for mold to grow, the presence of mold is also an indicator of another significant problem to building materials.  That problem is moisture, and moisture is not a welcome element in excess quantities in any building product.  If you remove the moisture then mold can not survive.

Molds outside of the home are generally not in a concentrated form in the air and mostly located in piles of decomposing materials in out of the way places.  In a spore form they move about freely in the air around us.  Winds and other factors generally keep mold spore counts down to livable levels.  Molds growing in a home though have less freedom to move about, can be spread around through the air movement in a home, can reproduce and gather in larger colonies, and can cause health problems.  Mold can create allergens that can cause respiratory issues, as well as aggravate existing conditions such as asthma.  Some of the potential symptoms of mold induced allergies include sneezing, chronic cough, runny nose, nasal congestion, itchy/watery/red eyes, skin rashes/hives, sinus headaches, aggravation of other respiratory issues (i.e. asthma as discussed), among other potential signs.  Remember that these are only potential symptoms and there are other issues besides mold that can cause these symptoms.

In addition to the allergens, and their symptoms, some of the more aggressive mold species also create chemicals called mycotoxins.  As its name implies a mycotoxin is a toxic byproduct of mold that can have detrimental health effects to humans and animals if swallowed, inhaled, or sometimes even in contact with the skin.  The effects of these mycotoxins run the gambit from dizziness and unexplained nose bleeds to the extreme of death if exposure is significant and prolonged.  Before you reach these extremes though you should already be visiting your physician for the lesser allergic symptoms.  Being alert for the causes of mold, and proper visits to your physician when the allergic symptoms arise, should be enough to prevent mold from having a significant effect on your health.

[tab: Inspecting]

Inspecting for mold is a basic two prong approach.  The first is the obvious visual approach to identify suspected areas of actual mold growth.  The second prong is to identify the main contributor of mold growth which is excessive moisture.  Without moisture mold can not survive.  So it stands that to eliminate mold you must eliminate the cause of excessive moisture.  Excess moisture causes come in many forms.  The most obvious are water leaks from plumbing fixtures, standing water in showers and tubs, condensation forming and dripping from pipes and window frames, as well as leaks in the homes exterior protective envelope (roofs, exterior walls, etc.).  If left unchecked not only can these conditions contribute to mold growth, the moisture can also damage building components on its own.

Along with these obvious causes there is another cause that many people do not even realize exists.  With the advent of newer construction requirements and methods our homes have become more and more airtight, and sealed against the elements outside.  This was done for greater energy efficiencies but has created yet another problem.  Inside of our homes there are many contributing factors to high levels of humidity which is the amount of water vapor in the air.  Some sources include normal cooking without the benefit of a range hood that exhausts to the exterior, cleaning of clothes and dishes which releases some water vapor, taking hot showers with poor ventilation systems in bathrooms to exhaust the steam to the outdoors, other mopping and cleaning activities, and even the human body releases moisture in the air around it.  As a result of the tighter construction other methods are needed to help control and reduce the indoor humidity to acceptable levels not only for human comfort, but also to prevent the conditions that support mold growth.  These methods of control are an extensive subject on their own but it is enough to say that they are not emphasized sufficiently in many cases of home construction.  As a result even a home with no obvious water leakage problems exhibits the potential for mold growth.

During a normal home inspection the Inspector can identify suspect areas of mold growth and look for excessive moisture conditions.  The visual steps are obvious water staining on walls, ceilings, floors, around windows and doors, all of which are signs of water penetration of the building envelope and/or plumbing pipe leakage/condensation in and on walls.  The areas around plumbing fixtures are checked which includes removing any access panels that are not permanently secured in place.  Other areas checked are around appliances that use or create water such as leaking or sweating water heaters, leaking dishwashers, clothes washers, water filtration systems, and air conditioning condensation coils that exhibit signs of condensation overflow in the overflow pan.

Some Inspectors have additional training and equipment at their disposal to help search out and identify abnormal water sources and issues.  The three most useful pieces of test equipment for this are thermal imagers (Thermography), moisture meters and hygrometers.  A thermal imager is used to scan large areas for the temperature differences in materials that can potentially indicate the presence of moisture.  This is a very controlled process which requires manipulating the temperatures of the materials being scanned in an attempt to force the wet areas of materials to display themselves.  If properly performed the wet areas will be displayed on the imager as temperature differences than the surrounding dry areas.  With Thermography the Inspector can scan large areas quickly to locate potential problem areas.  Once located these wet areas are then verified with the use of a moisture meter which provides relative readings of moisture in materials.  Moisture meters can be used by themselves, without Thermography, but only on much smaller areas.  A moisture meter is a contact device and would require extensive and unrealistic amounts of time and effort on larger areas in search of moisture problems.

The last piece of equipment mentioned was a hygrometer.  This is a device to measure the relative humidity in a home which is the amount of moisture in the air around you.  It is simply amazing at the amount of moisture that can be produced by uncontrollable events in your home.  For example the act of a person breathing can introduce 3 pints of moisture a day, a typical shower with ventilation fans running is 1 pint which includes your towels drying,  if you live over a basement or crawlspace the moisture in the soil can introduce up to 100 pints a day, and the natural drying of building materials from a humid day outside can produce upwards of 16 pints a day.  These are some of the uncontrollable contributors of moisture in a home and do not even include the other activities described above.  The acceptable limits of relative humidity in a home are based on many factors but are generally agreed to be from a low of 25% in the Winter months to a high of 60% in the Summer months.  When the relative humidity reaches and passes 70% not only does mold grow but also dust mites thrive but extensive exposure causes metals to corrode and materials to decay quickly.

If you are experiencing possible mold issues and require specific inspections, testing, or remediation for mold alone then you should become aware of your State and local laws for these activities.  Many States require specialized licenses for these activities.  Here in Texas if you are hiring a person for the specific inspection, testing, and remediation for mold this does require a license beyond a normal Home Inspector’s license.  Texas takes this law very seriously and so should you!  During the course of a home inspection an Inspector can advise you of the potential presence of visible mold as well as the conditions existing for its growth.  However a licensed Real Estate Inspector, without the additional license, can not definitively identify a mold growth, can not perform tests to verify or identify mold growth, can not advise you of any corrective measures for mold issues, and can not perform any action to remediate the mold growth.  In Texas the Texas Department of State Health Services regulates mold inspection, testing, and remediation.  You can go to their WEB site for a list of licensed persons in your area.

You should also be aware that if moisture issues are found, and no visible signs of mold are present, this does not immediately indicate that mold is actively growing.  However high humidity, water penetration and leakage issues should never be taken lightly.  Under the proper conditions mold can start growing in as little as 24 hours.  Mold can easily grow in wall cavities, heating and cooling equipment,  and other enclosed areas, for long periods of time and not be readily visible.  Air currents flowing through these areas can easily find their way into the home and spread mold spores throughout the home.  The only way to tell if mold is present in those damp areas, outside of visible signs, is to perform mold testing and potentially removal of wall coverings, cabinet bottoms, etc., etc., to verify the growth.

[tab: Testing]

There are literally 100,000 named types (species) of mold with many more still unnamed.  Of those there are approximately 1000 types that are commonly found indoors.  All molds have the possibility of causing health issues, and some molds are even toxic.  Mold needs water to survive and water in hidden spots can be a growing place for mold.  With so many mold types in play a simple visual inspection can not always tell you enough, including what type of mold is present or what type of mold is visible.  With all of the uncertainty there is only one way to confirm the presence or absence of mold , if it is active, and what types are present.  To confirm these things requires a through and proper testing method(s) after mold growth is found, or potential mold growth is suspected.  Sampling comes in three basic forms of “Surface Sampling”, “Bulk Sampling”, and “Air Sampling”.

Surface sampling is used to confirm what type of mold is present if an area appears to have visible signs of mold, and to rule out the possibility of mold on an area that contains staining that appears to be mold.  Under some situations, even though visible signs are not present, there might be a need just to verify if mold is even present and what its type is.  Surface sampling can be used to perform this verification although rarely done without suspect areas.  Surface sampling can be performed either by using a sterile swab which is rubbed across a suspect area, or by using a piece of test tape, applying it to the suspect area to lift a sample from the surface.  Both of these samples are placed in proper sample containers and sent to a laboratory for analysis.  Both of these methods are typically used on nonporous and smooth surfaces to ensure a proper sample is taken.  Each of these sampling types does have disadvantages that you need to be aware of.  The swab sampling will potentially limit identifying all of the mold types present as some parts of the sampled material could be destroyed in the process.  Tape lift samples can not extract the mold from the tape and as a result the sample can not be cultured to see which mold organism types are alive.  Also the tape lift method can not be used on surfaces with excess other dirt and materials as they can interfere with lifting mold itself.

The “Bulk Sampling” method is used when the surfaces or materials to be tested are too porous or rough for the swab or tape lift methods.  With this method sections of the surface, or pieces of the entire material, are very carefully cut away.  These samples are properly packaged in sample containers on shipped to the laboratory for analysis.  In the laboratory they are rinsed with a solution to draw the mold off of the item and placed on an appropriate medium for culturing, testing, etc.

“Air Sampling” is used if the conditions dictate the need, or the mold issue is severe enough.  The purpose of air sampling is to collect and identify airborne mold spores, other mold components, and potentially identify the levels in the air.  There is a passive and active method for performing air samples.  With the passive method a sample collection device called a “Settling Dish” is placed on a surface and will collect mold spores and components that are heavy enough to settle out of the air and into the dish.  As can be seen this type of testing method is not very accurate on mold counting or even the types of mold present in the air.  It only collects those types and components that are heavy enough to settle into the dish.  The active method of air sampling uses an air pump that draws air in from around it and runs it over a collection medium to capture mold spores and mold components floating in the air.  This active method is obviously more accurate than the passive method.  Since mold is in the air all around us, all of the time, the indoor samples alone can not provide an idea if the indoor levels are abnormally high.  To help determine this one or more samples will be taken outside of the home as well.  The types and counts outside will be compared to the types and counts inside to help determine the severity of the problem inside the home.  All of these samples are sent to a laboratory for proper analysis.

The number of samples needed for any analysis of a mold problem is determined by the specially trained and licensed Mold Assessment Consultant.  There are many factors they use to make this determination.  Part of the factors is the testing protocol that is used either by choice, or potentially dictated by rules or laws. or by their training and available equipment.  Each sample generally results in a charge by both the Consultant and the laboratory who performs the analysis.  Your Consultant should be providing you a description of their testing procedure, how many samples they feel are needed, why the Consultant feels they are needed, and what the charge will be to you.  Depending on the severity of the mold issue the inspection, testing, and lab analysis fees can be relatively large.  Keep in mind though that you do have some control over this process but also must exercise good judgment when it comes to the health and safety of you and your family.  Possibly not all samples are needed, and then again the Consultant might already have reduced the sample numbers to the lowest level in an effort to manage your costs yet still obtain the needed information.

[tab: Remediation]

Mold remediation is the process of eliminating the initial cause of the mold, clearing the area affected by mold, and also the steps needed to help ensure the initial problem does not occur again.  There are various methods and steps for remediating mold and they can be as simple as cleaning the surface of an affected area all the way through setting up of containment areas and removing severely affected components of the home (sheetrock, insulation, cabinets, etc.).  Every situation is different and it is the function of the Mold Assessment Consultant (at least here in Texas) to assess your situations needs.  The Consultant will perform the inspection and testing to obtain all of the information needed.  Using the inspection and test results a remediation plan will then be written to handle your particular situation.

Two major factors used in the creation of a remediation plan are the extent of the mold problem, and the type of mold present.  Typically with very small and defined areas, that have not affected building materials to the point of requiring removal, the owner themselves might well be able to perform any remediation steps needed.  For non porous materials such as glass, plastic, metals, etc., the mold is typically limited to mold growing in the dust and dirt on the surface of the material.  These can generally be cleaned with an appropriate biocide cleaning agent.  Some molds require the specification of particular biocides that will completely kill that type of mold.  Once the mold is killed it must still be cleaned from these surfaces.  Cleaning after using the biocide is important as the mold still can be allergenic and toxic even after it dies.  Your mold Consultant will advise you if it is a simple enough job, what biocides and cleaners to use, and any other necessary steps to take.

For more porous materials the issues become harder to deal with.  Materials such as sheetrock, carpet, furniture fabrics, etc., tend to become impregnated with the mold and its components.  Under these circumstances the only effective way to completely remove the mold is to remove and properly dispose of these materials.  After the removal the exposed building components are treated with biocides, cleaned, and then an encapsulating material rolled, sprayed or brushed on.  The encapsulating material is to seal in any microscopic amounts of dead mold and prevent it from re-emerging.

The more extensive remediation jobs will most likely require the creation of containment areas around the affected materials.  The containment areas are created to prevent any further spread of mold spores to unaffected areas of the home.  Also used are special ventilation fans with filtering equipment, respirators and protective clothing for the workers, special containers for placing the removed material in for disposal, and other specialized requirements.  Large mold problems are nothing to take lightly and the remediation people are exposed daily to these conditions.  During any major remediation effort the remediators will be following the plan and guidelines set forth by the mold consultant.  If at any point during the remediation efforts the problem is found to be larger than originally expected additional actions will need to be specified by the mold Consultant.  Also the Consultant will generally make regular visits to the site to make sure the plan is being followed.    Once the remediation work is considered completed the mold Consultant will again run a series of inspections, samples, and tests to make sure the remediation was successful.

All of the specific steps should be spelled out to you by the mold Consultant.  The Consultant can answer any of your questions and advise you of the potential for more in depth remediation if hidden issues are found once the work begins.

[tab: Prevention]

There is no doubt that to prevent experiencing potential large mold problems is to exercise due care and prevent mold from occurring in the first place.  These are some steps you can take to help prevent having mold problems.

  • Immediately repair any leaking plumbing no matter how small, and regardless of inside or outside of the home.
  • Do not stuff sink cabinets full of items.  It is better to allow plenty of room not only to regularly inspect for leaking under them but also to allow air in them to dry any moisture that does occur.
  • Caulk the bases of bathroom and kitchen fixtures and cabinets, as well as baseboards on walls with tiled floors.  Repeated mopping, as well as other water sources, can cause standing water under edges.
  • Ensure that you have a working window, or bathroom exhaust fan and they are used when showering or bathing.  The exhaust fan should terminate directly to the outdoors and not into the attic or into the soffit area.
  • Ensure that the joints are properly between counters and back splashes and around sinks and counter surfaces to prevent spills and excess water from migrating behind cabinets.
  • Have your heating and cooling system serviced regularly to ensure the condensation overflow is not active (primary condensation drain line blocked).
  • If your area is subject to regularly high humidity levels outdoors speak with your heating and cooling people to determine if indoor humidity is higher than needed, and what can be done to reduce it to lower levels.
  • Routinely check exposed plumbing, water heaters, water softening equipment, etc., for leaks and condensation issues.
  • If you cook heavily and frequently and do not have a range exhaust vent that terminates to the outdoors then consider adding one.
  • Routinely check, empty, and clean refrigerator drip pans if present.
  • Be vigilant for water staining and condensation on interior ceilings, walls and floors.  These could be indications of leakage.
  • Ensure your clothes dryer is properly vented to the outdoors and the vent and hose is kept clean and clear of obstructions.  If you do not have an exhaust fan for the laundry room area you might consider adding one to vent off moisture from the washer and dryer operations.
  • If you have saunas or hot tubs in enclosed areas ensure the area has proper ventilation to the outdoors to draw off excessive moisture from steam.
  • Perform routine inspections on your roof and correct any issues immediately to prevent leaks.
  • Perform routine inspections on your windows and doors to correct failing caulking and seals to prevent leaks.
  • Ensure that you have 4″ – 6″ clearance of your exterior siding materials to the surrounding ground.  You should see 4″ – 6″ of foundation wall.  Make sure the grade around your home is sloped sufficiently to carry water away from the foundation.  This will help prevent excessive water near the foundation from entering at the bottom framing members.
  • Do not allow sprinkler systems to spray on the home to prevent potential water entry as well as damage to exterior sidings.
  • Keep exterior woodwork properly treated/sealed/painted to prevent damage and deterioration that could cause gaps for water entry to the home.

There are many good WEB references for mold, its issues, inspecting, testing, and remediation, as well as guides to help you better understand the potential seriousness of unchecked mold growth.  Some references have been provided for you on the next tab.

[tab: Links and References]

Texas Department of State Helath Services Mold Program

Texas Department of Insurance Mold Resource Page

US Environmental Protection Agency Mold and Moisture Page

Centers for Disease Control and Prevention

National Institute of Environmental Health Sciences – National Institutes of Health

US National Library of Medicine – Medline Plus

US Department of Housing and Urban Development (HUD) Mold and Moisture Page

American Lung Associations Health House Project

American Industrial Hygienist Association

Building Science Corporation – Mold Reference Series

Doctor Fungus

National Institute of Building Sciences – Mold Remediation Guidelines

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