Download - Moisture control eguide
Indoor Moisture Control
A Comprehensive eGuide
Flood Damage Pro | Water Damage Restoration | 866-869-4167 | www.flooddamagepro.com © 2005-2014 All Rights Reserved
Table of Contents
Addressing Mold: Indoor Moisture Control .................................................................................................. 2
Mold Spores in the Air .............................................................................................................................. 2
Water Sources for Mold Growth................................................................................................................... 3
Leaks and Floods ....................................................................................................................................... 3
Water in the Air......................................................................................................................................... 3
Humidity ........................................................................................................................................................ 4
What is Relative Humidity? ....................................................................................................................... 4
Measuring Humidity ................................................................................................................................. 4
Effects of Low Humidity ............................................................................................................................ 5
Effects of High Humidity ........................................................................................................................... 5
Is Condensation a Sign of High Humidity? ................................................................................................ 6
Temporary Increases in Humidity ............................................................................................................. 6
Mold and Your Health ................................................................................................................................... 7
Common Reactions to Mold ..................................................................................................................... 7
Is it Mold or Something Else? ................................................................................................................... 7
Toxic Mold ..................................................................................................................................................... 8
Treating Mold ............................................................................................................................................ 8
Controlling Indoor Moisture ......................................................................................................................... 9
Water Damage: Water Extraction and Controlled Drying ........................................................................ 9
Reducing Relative Humidity ........................................................................................................................ 10
Increase Air Temperature ....................................................................................................................... 10
Vent Appliances ...................................................................................................................................... 10
Insulate Pipes and Ductwork .................................................................................................................. 11
Use Exhaust Fans .................................................................................................................................... 11
Air Conditioning ...................................................................................................................................... 12
Keep Humidity Outside ........................................................................................................................... 12
Home Dehumidifiers ............................................................................................................................... 13
A Word from Flood Damage Pro ................................................................................................................. 14
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Addressing Mold: Indoor Moisture Control If you see visible signs of mold on the walls or ceiling or can smell a musty, moldy odor, you may have a
mold problem in your home or business. Where there's mold, you can be certain that there is water as
well.
Any treatment to get rid of the mold must also remove the source of the water. If this is not addressed,
mold will grow there again in the future.
Mold Spores in the Air Mold is a fungus which reproduces by sending out spores into the air. Mold spores are too tiny to be
seen and are always present, both indoors and outdoors. They float on the air from place to place, just
like pollen does. When the spores encounter moisture, mold growth does not start immediately.
However, mold growth will begin within 24 to 48 hours.
Mold remediation arrests mold that is actively growing and removes it. However, it is simply impossible
to completely eliminate all mold spores from our living and working environments. For susceptible
individuals with mold allergies or asthma, this is bad news. Mold allergies and asthma are triggered by
breathing in the spores. The good news is that there are ways to minimize the amount of mold indoors.
Mold can only grow when the following conditions are met:
1. There must be moisture. Mold cannot grow without moisture.
2. Mold needs nutrients. This can be food or other organic materials, but it can just as easily be
cotton and other permeable fibers.
3. There must be a sustained moderate temperature. Typically this means between 40° F and
100° F. If it is colder or hotter, mold won't grow, and mold grows most between 70° F and 90° F
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Water Sources for Mold Growth
Leaks and Floods Whether from a leaky pipe or from a heavy rainstorm, when water soaks your home or office, you have
to make sure the area gets dried again quickly. Water damage is an emergency that justifies an
emergency response. But what is the nature of the emergency?
It all comes down to those 24 to 48 hours, that window of time to prevent mold growth before it starts.
Once mold starts growing, mold remediation is necessary to make sure that the mold is completely
removed. Removing the moisture alone won’t kill the mold. It will merely become dormant, ready to
reactivate when it gets wet again.
In most cases, if wet or damp materials are completely dried within 24 to 48 hours after the leak or spill
occurred, mold will not grow. That's why the first response to water damage is to remove excess water,
and the second response is to employ drying equipment to speed the drying process. This drying
equipment often includes powerful air movers and dehumidifiers.
Water in the Air Remember that sticky, uncomfortable feeling from a hot, humid day? You can feel the moisture in the
air with every breath you take. People are very sensitive to humidity level as it relates to their comfort.
In fact, lower humidity is perceived as colder and higher humidity as hotter, even at the same
temperature.
Humidity is literally water in the air. High relative humidity at home or in the workplace affects more
than just our comfort. By supporting mold growth, humidity affects our health. Note that normal indoor
temperatures fall in the perfect range for mold growth, so high humidity can make mold growth
extremely likely.
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Humidity
What is Relative Humidity? When people talk about humidity, they’re really talking about relative humidity. Relative humidity
measures the percent of water saturation in the air, based on how much water the air can hold at that
temperature. Warmer air holds more water than cooler air, which is why it is so much more common to
have really humid weather in the summertime. And relative humidity affects the rate that water
evaporates. On a hot day with low relative humidity, water will evaporate rapidly. For this reason, it is
really important on a hot day with low relative humidity to make sure you drink enough water, as you
can get dehydrated easily without realizing it.
Relative humidity in your home can increase in two ways; either the temperature stays the same and
more moisture enters the air, like taking a shower and letting the bathroom get steamed up, or the
temperature drops, and the same amount of water is now a higher relative humidity since the cooler air
can hold less water overall.
Measuring Humidity You can measure the exact relative humidity in your home with a humidity monitor called a hygrometer.
They are readily available at stores like Target and Home Depot, with a digital display that tells you the
current temperature as well as the relative humidity. These go for about $10 to $20, and you can buy
low-tech versions for even cheaper.
If you just want to know whether the indoor humidity in a particular room is too low, you can find out
with a glass of ice water. Fill the glass with water and add a few ice cubes. Wait around three minutes,
but don't move around too much in the room, as you can change the humidity level that way. Check if
water has condensed on the outside of the glass. If not, then the relative humidity in that room is too
low.
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Effects of Low Humidity People are most comfortable with relative humidity that is between 30% and 50%. When humidity is
lower than 30%, it can impact you and your possessions negatively.
When you get shocked by static electricity in the winter, it is due to low relative humidity indoors. Low
humidity is more common in colder climates, and in the winter time.
Low humidity can cause you to have dry, itchy skin and dry eyes. Drier mucus membranes in your nose
and throat can make it more likely that you will catch a cold or other illness.
It can even affect your furnishings. Wood absorbs moisture when humidity is higher but can dry out if
humidity is too low. So hardwood floors can shrink and even crack. Wallpaper can begin to peel off as
well.
Even houseplants react to low humidity; the tips of their leaves can turn brown and dry. There is a high
tendency to over water houseplants in the wintertime when humidity is lower.
Effects of High Humidity High humidity (above 60%) can cause problems for almost all of your furnishings. High humidity can
cause mold to grow in carpets, rugs, and on upholstered furniture, as well as in permeable building
materials, like ceiling tiles and drywall.
Wood floors are particularly susceptible to moisture levels and can buckle and cup from sustained high
humidity.
Paint can begin to flake off the wall, and drywall can start to fall apart.
Moisture can condense inside air ducts, giving mold more places to grow.
Both dust mites and cockroaches thrive in high humidity, and the increased amounts of allergens they
create with their waste can trigger attacks in asthmatics and people with allergies.
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Is Condensation a Sign of High Humidity? Condensation inside your home, whether on walls, pipes, or windows, can be a sign of high humidity.
This humidity is usually due to reduced air flow inside your home. When buildings are constructed to be
more energy efficient, the normal air flow that could reduce indoor humidity is cut off.
When water condenses inside the home, you should not only dry the wet surfaces, but you must also
locate the source of the moisture. It could be there is a leak somewhere around the window or near the
wall that should be repaired. Or you may have to take greater steps to address the higher indoor
humidity. See Reducing Relative Humidity for more information.
Temporary Increases in Humidity There are common day-to-day activities that can cause higher humidity temporarily in part of your
home.
These include:
showering
cooking
breathing
watering houseplants
But these incidences of increased humidity needn't lead to mold growth in a home where the humidity
is typically lower. Remember, mold needs humidity to be higher for a sustained period of time, 24 to 48
hours. So raising humidity temporarily is only dangerous if it is more than occasional and does not
disperse afterwards.
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Mold and Your Health
Common Reactions to Mold Studies have found that exposure to mold can affect the health of allergic and non-allergic individuals
alike. Even in a person who is otherwise healthy, the body's reaction to mold can mimic illness in many
ways. It can seem like a bad cold, with nasal congestion and wheezing. Eye irritation and itching is also a
typical sign of mold exposure.
Like most allergies, mold exposure can also cause hives or a raised, itchy rash from direct contact of the
skin with active, growing mold colonies. The direct contact could be indoors, or even from mold in the
yard during yard work.
These minor symptoms can occur in allergic individuals and in individuals who are sensitive to molds. In
more severe cases, mold can cause fever and shortness of breath. Immunocompromised individuals can
suffer more severely from mold exposure, possibly developing a pulmonary fungal infection.
Is it Mold or Something Else? The difficulty in identifying minor reactions to mold is that many of these symptoms also occur in other
illnesses and allergies.
If the symptoms seem more allergic than viral, or last much longer than you might expect a cold to last,
it makes sense to look for these mold risk factors:
Your home has high humidity (higher than 60%) on a regular basis.
There are visible signs of mold growth on walls or furniture.
There has been water damage to the property in the past.
You smell a musty, moldy odor.
Your child is sick more often than other children.
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Toxic Mold If you have heard of toxic black mold (Stachybotrys chartarum), and worried which type of mold is in
your home, you should know that the risk of additional health concerns from Stachybotris chartarum
and other toxigenic molds is very small and has not been definitively linked through scientific research.
The Environmental Protection Agency and the Centers for Disease Control and Prevention and do not
recommend testing the mold to see what type it is. They do, however, recommend removing any active
mold growth, regardless of the type..
There are more than 100 distinct types of mold, and any active mold growth should be addressed
promptly and removed from your living environment. Recent studies have shown a link between early
mold exposure and the development of asthma in predisposed children.
Treating Mold For small amounts of mold, you can treat it yourself, but for larger affected areas it is prudent to hire a
mold remediation specialist. A mold remediation specialist can address the moisture source that caused
the mold to grow. Until this moisture source is removed, mold can easily return in the same location.
Complete mold removal is also required. When you take away the source of moisture, mold doesn't die
but becomes dormant and can remain until there is another moisture source. So mold must be actively
removed, and permeable surfaces that cannot be completely cleaned of mold must be discarded.
For more information about mold, please see these excellent resources:
http://www.cdc.gov/mold/faqs.htm
http://www.mayoclinic.org/diseases-conditions/mold-allergy/basics/definition/con-20025806
http://www.epa.gov/mold
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Controlling Indoor Moisture To control mold growth, you need to control sources of moisture indoors. The two main sources of
moisture indoors are water damage from leaks or damaged and high relative humidity. With the rapid
growth of mold in moist environments, you can’t afford to procrastinate when it comes to excess
moisture indoors.
Water Damage: Water Extraction and Controlled Drying When there has been just a small leak or a minor spill, wipe it up as best you can as soon as possible.
That way it will have a good chance of drying completely before mold can start growing.
When there is more widespread water damage, the job is a little more involved and may require special
equipment. There are two main phases in the drying process:
1. Water removal using professional water extraction equipment to remove excess sitting water
2. Controlled drying using air movers and dehumidifiers
It is easy to understand why water removal is necessary, but the reason for using drying equipment after
water removal may be less obvious. This has everything to do with the water cycle (see
http://pmm.nasa.gov/education/water-cycle for a good explanation) and how water evaporates into the
air. In a closed building with limited ventilation, when objects or surfaces dry, the water that evaporates
into the air has nowhere to go. This causes relative humidity to increase and with it the likelihood of
mold growth.
Air movers help increase ventilation to move more of the humidity from the closed structure, and
dehumidifiers remove the moisture directly from the air. Both aspects are necessary to make sure that
the area dries in time to prevent secondary damage from mold.
Since it may not be possible to adequately remove mold from permeable surfaces, preventing its growth
in the first place can save many belongings from certain disposal and may limit damage to the structure
of the property as well.
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Reducing Relative Humidity For health and comfort in the home, the relative humidity should be between 30% and 50%. But
everyday activities can increase the relative humidity. Some temporary increases in humidity can occur
after showering, cooking, washing dishes, and even watering plants. To return your home to its normal
humidity level, some ventilation is in order.
When humidity is more systemic, you need to look a little more closely at the possible sources for the
increased humidity. Crawl spaces, attics, and anywhere that rain and other precipitation can slip in
should be addressed. Humidity can be consistently kept lower through a combination of ventilation, air
conditioning (according to the season) and using a home dehumidifier. Be cautious in how aggressively
you lower the humidity. Indoor humidity must be carefully balanced. Just as too much is bad, too little
humidity is bad, too.
No matter which method or methods are employed, be sure to monitor the humidity closely with a
hygrometer to track the effectiveness of the measures used.
Increase Air Temperature One of the simplest ways to lower relative humidity is to increase the temperature. When the air is
warmer, the relative humidity goes down automatically, as warmer air can hold more moisture.
However, this is limited in use, as the hottest months are also the most humid, and you usually don’t
want to make it hotter.
Vent Appliances Any appliances that produce moisture in the course of their regular operation need to be vented to the
outdoors. A good example of this is the clothes dryer, which generates a lot of humidity. Most dryers are
vented to the outdoors, but keep in mind that the venting only works if the dryer vent is clear. Lint
blockages can obstruct venting of the moisture-laden air, forcing the humidity to be released into the
laundry room instead. If you find that your laundry room feels more humid than the rest of the house
during or after drying a load, then dryer vent cleaning may be required.
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Insulate Pipes and Ductwork Some sources of moisture indoors are hidden from view behind walls, ceilings and cabinet doors. These
are the water pipes and air ducts. Even when the relative humidity is in the right range, water can
condense on cold water pipes and on air ducts. Insulating the pipes and ductwork will prevent this
condensation from occurring and causing localized damage to your property.
Use Exhaust Fans For temporary but recurring increases in humidity, there are built in solutions. Have you ever wondered
why there is a fan in the bathroom? Have you wondered how and when to use it? Many people don’t
realize that the bathroom fan was installed to remove moisture and humidity after a bath or shower.
Without ventilation, bathrooms can quickly become dank and full of mildew.
It may have its own switch, or it may come on automatically along with the light switch. According to the
Home Ventilation Institute, the fan should run both during and for at least 20 minutes after the shower
or bath is completed. Don’t be tempted to turn off the fan earlier even if the room seems back to
normal, as the full time is required to remove the water droplets from the exhaust vent ducting as well.
If you don’t have a fan, cracking the window open will help get rid of the excess moisture, but it is not as
effective. For convenience, you can even install a timer on the fan so that it will automatically turn off
after the required time has elapsed.
In the kitchen, a vented cooker hood performs much the same job as the fan in the bathroom, removing
moisture generated by cooking. In addition, the cooker hood filters the air, removing airborne grease
and odors. If you have a recirculating hood instead, it does not remove moisture from the air, so
increased ventilation from opened windows, doors, fans or air conditioning can be very helpful in the
kitchen.
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Air Conditioning In hot and humid weather, air conditioning cools indoor air as it also removes moisture. The air
conditioning unit draws indoor air in and passes it over the evaporator coils, where the air is cooled and
the water that condenses is collected and removed from the structure.
People sometimes complain that their air conditioner does not dehumidify or may even increase the
relative humidity. This is usually due to an inappropriately sized air conditioner for the space.
When an air conditioner is too powerful for the space it is supposed to cool, it will cool too rapidly. Then
it shuts off before it has an opportunity to condense the water vapor. This rapid cooling can increase the
relative humidity if it is not condensing the water before returning the air to the living space, since the
cooler air can hold less moisture than the warmer air.
Air conditioners that are too small for the space are simply too weak to remove enough moisture from
the air.
Keep Humidity Outside Especially in humid climates, vented crawl spaces can draw in more humidity than the ventilation
removes. Encapsulating the crawl space can help prevent this, but then there is the new problem of how
to depressurize the air underneath the home. A dehumidifier can be installed successfully to address the
air quality issues and reduce humidity entering the structure from the crawl space.
It also makes sense to look at the rain pathway to identify places where moisture can enter the
structure. This can be through the roof and walls, but could also be from areas around windows and
doors. If you seal these air leakage paths, you can prevent humidity from pooling in attics and wall
cavities.
Gutters should also be kept clean and in good repair, to keep rain water away from the foundation and
out of the basement.
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Home Dehumidifiers Last but not least, running a dehumidifier can remove water directly from the air. The water is then
deposited in a collection tank which has to be emptied on a regular basis, or a hose can be connected to
the dehumidifier so that the condensed water flows directly to a drain. Many times, dehumidifiers are
used in basements, and directing the water to the drain is convenient and effortless.
A dehumidifier works very similarly to an air conditioner. It also takes in air from the room, and passes it
over evaporator coils to cool the air and condense the moisture. The dehumidifier then warms the air
again as it blows it back into the room.
Humidifiers can be used safely, as long as you follow a few simple guidelines.
Humidifiers are not recommended for use in the winter, as they can reduce the relative
humidity too much.
When using a dehumidifier, it is also beneficial to increase the ventilation to the area.
Dehumidifiers do not ventilate the air that they process. Nor do they filter it. It is simply the
same air, circulating over and over through the basement. Without introducing fresh air,
allergen levels in the air can increase and make indoor allergies worse.
Follow the manufacturer’s maintenance instructions. It may seem like a pain, but the
instructions are designed to keep the machine up and running properly, as well as reducing the
risk of bacteria and mold growth. Because the dehumidifier deals with water, bacteria or mold
that grows inside the dehumidifier could be blown into the air.
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A Word from Flood Damage Pro
Thank you for taking the time to read our eGuide. We hope that you know a little bit more now about
the importance of monitoring and treating humidity at home. Information is powerful, and it is our goal
as a service provider to keep open and clear lines of communication in all our endeavors.
If you would like more information on moisture control or are interested in finding out about mold
remediation and water damage restoration, please feel free to give us a call. You can also find additional
information on our website, www.flooddamagepro.com.