Tips on Mold

Some mold species are toxic. If mold is present, as a safety precaution, you should:

Wear protective gloves (plastic or latex)

Wear long sleeves

Use a respirator

If any health effects are observed, contact a doctor immeadiately.

Mold and mildew can have an adverse effect on people. Many fungi will seriously irritate and inflame lungs. Some fungi can cause skin and eye irritations and infections.

Prolonged exposure to active mold in an enclosed area can damage the lungs, mucous membrane, cornea, respiratory tract, stomach, intestines, and skin.

Before you treat mold outbreaks, try to determine what has caused it in the first place. You need to pinpoint whatever caused the mold to develop and then fix it, because until you solve that problem, mold will continue to grow no matter how often you treat the affected material.

Look for a source of water, such as an unnoticed leak, broken window, or moisture along outside walls.

Check the heat-exchange coils in the heating/air conditioning system. They are a prime area for fungus growth and spore distribution. Clean with a normal fungus-killing household cleaner.

Active mold looks fuzzy and has a musty ordor. Do not attempt to remove active mold, it must be dormant for removal. Attempting to clean active mold will result in stains that are often impossible to remove.

Increasing the air circulation will dry most books and active mold efficiently. It would be ideal to have several fans circulating the area to accelerate the evaporation and drying process.

Do not shelve or store books directly against an outside wall. Due to temperature and humidity differences between inside and outside environments, moisture may develop along walls.

Install or adjust outside gutters and drains so that water does not collect near the outside walls. Check gutters and drains regularly to avoid clogs.

Waterproof basements and walls below ground level. Use water-sealant paint on floors and walls. Allowing air to circulate against the walls will enable the moisture to evaporate.

Freezing the moldy book may be an option for halting the spread of mold while you evaluate other methods for killing the active mold. Freezing will stop the growth, but it must still be cleaned.

Dormant mold is dry and powdery in appearence. It may also have a musty smell. It can be removed using a vacuum cleaner and a soft brush or a brush attachment. Clean brushes and dispose of vacuum bag to prevent spreading the mold spores.

Charcoal and/or baking soda can be used to remove the odor of mold. Place briquettes and/or bowls of baking soda in the area to absorb the odor.

Damp books are more susceptible to mold than wet volumes.

Mold will start on covers and work inward on a book. Many molds prefer the starch in cloth-coverings on books. Mold is often noted on the bindings long before it grows on the textblocks.

Low temperatures (below 68 degrees F) and humidity levels as low as possible below 75% will stop most mold growth.

In warm and humid conditions, mold can begin to grow within 24-48 hours after the materials have gotten wet.

The spores of fungi that become mold or mildew are always present in the air and on objects. When the temperature and moisture in the environment are suitable for germination, the fungus spore bursts and growth begins.

Potential Mold Producers & Hidden Incubators

Micro-climates, and the higher humidity levels they typically have, can be major mold producers in a home. Humidity levels in a house are a key element in reducing and/or controlling the growth and spread of mold and mildew.  The typical comfort range for indoor humidity in northern climates is approximately 30% - 40%, in the winter months.  While indoor "core" humidity levels can be kept relatively stable, and easily sustained at or about 40% RH (relative humidity), "micro-climates" can easily double this.

Basement Water Leakage

If your house has a basement, then basement water leakage and excess basement humidity levels are likely the number one contributors to mold growth in your home.  It has been documented that at least "98% of all sub-surface basement areas will leak, at some point in their life."  In the over 5,000 home and commercial buildings I have inspected over the years, I certainly have found this statement to be true.

There can be many reasons for a damp or leaky basement (for more information on basement water problems, check out "Basement Water Problems" under Home Resource Materials), and they all add up to problems for you as a homeowner, if not corrected.  Actual water leakage should not be confused with the high relative humidity typically found in basements.   Both can pose serious problems, but need very different approaches to affect a cure.

Moisture trapped between the foundation wall and the finished basement wall can allow mold to grow unnoticed. Long-standing moisture problems can lead to decay, resulting in structural damage to the house.

View of an exterior basement wall, where water had been leaking in unnoticed, from a window well.  All the insulation and damaged framing had to be replaced, extending 10' on either side of the window.

View of an exterior finished basement wall, where a long-standing exterior drainage issue was left un-corrected.   The entire basement had to be gutted, in order to fully remove all the mold growth from the home.

View of mold growing on an unfinished block foundation wall.  Normal condensation on perimeter walls due to temperature differences, can lead to extensive mold/mildew growth.  Some type of de-humidification in a basement is a must.

Sump Basket & Drain Tile Systems

The perimeter drain tile system underneath a basement floor and the sump basket it drains into, both serve a very useful purpose. This system provides a key element in helping to protect your house from water damage, by providing an artificial "low level" drainage and collection point under your basement floor.  If the system is working properly, water should drain from the tile into your sump basket.  You can then pump the excess water collected in the sump basket, outside.

Since by its very design it is intended to carry and hold water, this system also provides an ideal breeding ground for bacteria, molds, and mildew.

Water seepage into the basement level can saturate the foundation walls, basement floor, and finishes.  Also, the drain tiles can hold moisture for a long period of time, allowing mold to grow unnoticed.

Water is often left standing inside a sump basket, providing an ideal breeding ground for mold.  The sump basket covers are frequently left open and due to normal pressure differentials, air from inside the drain tiles can be "pumped" throughout the house.

Air-Conditioners & Whole House Humidifiers

The condensate drip-pan, located on top of the furnace, can hold moisture for extended periods. Also,  the older drum-type furnace humidifiers can provide the necessary ingredients for mold growth.  In both of these systems their location is in very close proximity to an air-handling unit, which can allow mold spores to be quickly distributed throughout a house.

The AC condensate tray is very difficult to access, consequently it is very rarely cleaned.

Older rotating drum-type furnace humidifiers are notorious for providing harborage for molds.

Bathroom Related Mold Problems

Many times, mold growth can a direct result of poor maintenance. For instance, if the homeowner had maintained his ceramic tile (photo below left), he likely would not have incurred the expense of having to replace his shower.  Also, I wonder how long the mold on the drywall had been growing, and what health effects he may have been experiencing as a direct result of it?

View of damaged ceramic tile inside a shower stall, that has been leaking through to the drywall behind it.  Extensive mold growth and wall damage required that a completely new shower be installed.

View of mold growth inside an infrequently used shower head.

Strategies For Reducing Mold Growth In Your Home

Tips On How To Protect Yourself | Four Steps To Reduce Mold Growth

Some molds produce mycotoxins, and other active compounds that can be injurious to human (and animal) health.  In parts of Eastern Europe in the mid-1930's there were reported outbreaks of a new disease that affected horses and other livestock.  Subsequently, it was documented that mold in the hay fed to these animals was the likely culprit.  There have also been reported cases through the 1940's, where humans who handled hay infested with mold, or slept in mattresses filled with moldy hay, suffered some of the same symptoms as the livestock.

One type of mold, stachybotrys, presents a special health risk. If areas contaminated with stachybotrys are discovered in your home, or if you find areas in your home that are contaminated with mold and are unsure what type it is, don't attempt to remove it without first following the recommended safety procedures for persons working with toxic molds (i.e. use a respirator, gloves, proper covering for the skin & eyes, etc.).  I would also recommend that you get advice from a certified hygienist, or from your local Health Department.  You can contact the American Industrial Hygiene Association for referrals, at (703)849-8888.

Some Tips On How To Protect Yourself

Be aware of any noxious odors. When a mold colony is growing, it can give off distinctive odors that are the by-product of its metabolism.

Be familiar with the symptoms of a mold-related illness. Different mold species can produce different health effects.  Some of the common symptoms of mold allergy include a runny nose, itching of the eyes & nose, congestion, fatigue & general malaise.  Ask yourself, "Do my symptoms get better when I'm away from home for any length of time?"

Perform a visual inspection of your home.  Check out some of the more common places where mold could be growing in your home.  Look for any signs of past water leakage, check under sinks, in and around bathrooms, check out your basement (don't forget to look at your sump basket!). If you don't have a sealed cover over your sump basket, get one.

Contact a heating/cooling specialist to inspect and clean out your AC condensate tray, clean out and service your furnace humidifier, clean out and service the drip-pan under your refrigerator, etc.

Allow for good air flow throughout the interior of your house.  Keep furniture away from walls. Allow for adequate air-flow over your windows & doors, as they will be the largest condensing surfaces in your house and air-flow is needed to help evaporate moisture buildup.

Check your attic (roof decking, rafters, etc.) for any signs of darkening that could indicate mold growth.   If you notice any suspicious areas, contact a ventilation specialist for advice.

Check for any discoloration on walls or ceilings.  Often, this can be an indicator of moisture buildup, insulation problems, or ventilation problems that could be associated with future mold growth.

Be on the lookout for signs of excess moisture.  Do your windows frequently have moisture on them in the winter time?  Excess moisture is the single largest contributor to mold growth.

Is your heating/cooling duct work clean?  When was the last time you had your heat vents professionally cleaned and sanitized?