Mold and How to Prevent It

Many people are concerned about mold affecting their belongings in a storage area where the items won’t be touched for a long period of time.  This may be a legitimate concern, especially if belongings are to be stored in an attic, basement, or garage area that will be influenced by varying temperatures, potential moisture, and humidity.  Choosing the right local storage facility, however, may provide a solution to these concerns.  Carolina Storage Center offers climate controlled storage units that are designed to prevent mold development by maintaining the proper temperature and humidity level.

It’s important to understand the nature of mold and the elements that affect it’s growth in order to help you make a decision about where and how you can store your goods.

Molds are fungi that can be found both indoors and outdoors. No one knows how many species of fungi exist but estimates range from tens of thousands to perhaps three hundred thousand or more.

Outdoors, mold is important to the growth of all plant life. It’s nature’s way of providing a natural food source for our forests. Mold breaks down dead organic matter such as fallen leaves or decaying trees and turns it into nature’s compost.

Molds are found in virtually every environment and are everywhere all the time, indoors and outdoors, year round. Mold spores are microscopic (2-10 um) and are invisible to the naked eye (there are approximately 10,000 mold spores on the head of a pin) and float through outdoor and indoor air.

Molds reproduce by means of spores. Some molds have spores that are easily disturbed and waft into the air and settle repeatedly with each disturbance. Other molds have sticky spores that will cling to surfaces and are dislodged by brushing against them or by other direct contact. Spores may remain able to grow for years after they are produced.

Mold needs water and food. It can grow almost anywhere there is water, damp conditions or high humidity.

A mold spore landing on an indoor surface amounts to no more than a common component of indoor dust. However, when a mold spore lands on an organic surface (such as drywall) and the indoor humidity level of the surface on which the mold spore rests, is sufficiently high, the mold spore can propagate and spread, sometimes rapidly.

Mold thrives on natural fabrics and materials found throughout every home, office – or storage space. Mold attacks furniture fabrics, clothing, rugs and carpet. It grows on walls and ceilings – under flooring and on many others surfaces in your home or office. Indoors, mold can literally destroy your home or stored belongings.


While there are fungal species that are able to grow under a remarkably wide range of environmental conditions however, since a mold spore requires moisture to propagate and grow, keeping indoor humidity low will reduce the growth opportunities for the most common indoor molds.

Mold and mildew will not grow at levels of humidity lower than 50 percent.


Humidity is the amount of water vapor in the air. There are several different ways to measure and to express the amount of water in the air. Relative humidity tells how much water vapor is in the air as a percentage of how much it could hold at a certain temperature and pressure (at sea level for example). If air has a relative humidity of 50% it is 50% saturated. The relative humidity can change if the moisture changes or if the temperature or pressure changes.

The dew point is a much better indicator of moisture in the air and is preferred by most meteorologists. The dew point is the temperature at which the relative humidity reaches 100% or saturation.


Maintaining a “safe” level of relative humidity is generally thought to be a range of 30% to about 50%. Short periods of somewhat higher levels (60-65%) are thought to be acceptable.


The most widely used method of controlling relative humidity is to maintain a constant temperature range. In the self-storage industry the most common range is between 60°F and 80°F. Carolina Records Center maintains its facilities at this range.


In addition to temperature control, it is possible to remove humidity (water vapor) from the atmosphere of a room or storage unit by chemical means. This is done through the use of hygroscopic substances used as desiccants.

Hygroscopy is the ability of a substance to attract water molecules from the surrounding environment through either absorption or adsorption. [Absorption is the incorporation of a substance in one state into another of a different state (e.g. liquids being absorbed by a solid or gases being absorbed by a liquid). Adsorption is the physical adherence or bonding of ions and molecules onto the surface of another phase (e.g. reagents adsorbed to solid catalyst surface).]

Most hygroscopic material will tend to become damp and “cake” when exposed to moist air (such as salt in salt shakers during humid weather). Some hygroscopic substances readily dissolve in the water they absorb: this property is called deliquescence  (see below).


Deliquescent materials are substances (mostly salts) that have a strong affinity for water and will absorb relatively large amounts of water vapor from the atmosphere if exposed to it, forming a liquid solution. Due to their very high affinity for water, these substances are often used as desiccants. (A desiccant is a hygroscopic substance that is used as a drying agent.)

Instant coffee is an everyday example of a deliquescent. If you spill some instant coffee, the dry powder will turn into a sticky liquid when exposed to air for a few hours. The instant coffee powder is actually absorbing water vapor from the air. This is the same way that commercial desiccants remove moisture from your storage unit.

Deliquescent salts include

  • Calcium Chloride
  • Magnesium Chloride
  • Zinc Chloride
  • Potassium Carbonate
  • Potassium Phosphate
  • Carnallite
  • Ferric Ammonium Citrate
  • Potassium Hydroxide
  • Sodium hydroxide (caustic soda).


Pre-packaged desiccants used in the self-storage industry are most commonly used to remove excessive humidity that would normally degrade or even destroy products sensitive to moisture.

One such product is DAMPRID®.


DampRid® prevents mold and mildew stains and allergens caused by moisture by eliminating the excess moisture in the air that allows mold and mildew to grow. Mold and mildew will not grow at levels of humidity lower than 50 percent.  Once that optimal level of 50 percent relative humidity is reached, DampRid® slows down, and will restart when necessary.

How DampRid® Works

When the white pellets are exposed to the air, they absorb excess moisture and dissolve into a brine (salt solution).  They won’t dry the air to a level that damages plants, animals or clothing. The formula is non-toxic, septic safe and friendly to the environment. It’s safe for home, family and pets and is easy to dispose of after use.

DampRid’s Moisture Absorbers absorb moisture in three phases.

Phase One: Excess moisture is absorbed into the white calcium chloride crystals. The white crystals begin to harden and form a solid mass.  They have not yet dissolved.  You may see liquid dripping into the bottom chamber of the product at this stage.

Phase 1

Phase Two: Excess moisture will most likely be dripping into the bottom of the product.  Approximately 1/2 to ¾’s of the white crystals will have dissolved.

Phase 2

Phase Three: All the white crystals will have dissolved and the bottom of the product will be full of moisture.  You will still see a small line of yellow freshener beads in the top chamber of the Hanging Moisture Absorber.

Phase 3

Discard the DampRid product and replace with a new one.  For refillable products empty the collected liquid into the sink (with running water) or toilet and refill.

The timelines listed for each product should only be used as a guideline.  The product may last a shorter or longer period of time depending on the changes in the temperature and humidity.

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Carolina Storage Centers LLC Property Manager and Rental Agent 7205 US Highway 1 North Southern Pines, NC 28387 PHONE: (910)692-6103 FAX:(910)692-7923 Hours: facility 24/7 Monday to Friday 8:30AM to 5:30PM and Saturdays by appointment