Tips for Preventing Mold Growth in Basements

Basements are commonly a breeding ground for mold and mildew, but with proper water management techniques and the application of certain mold prevention products, your finished or unfinished basement can remain a healthy part of your home for years to come.

Mold can be especially hazardous to your health, especially with long term exposure. However, mold is ubiquitous and will always be found in every environment as 25 percent of the earth’s biomass is mold. Although complete elimination of mold is impossible, minimization is desired. The problem commonly lies in the fact that the basement is commonly the home of your heating and air conditioning unitand the supply air can push a tremendous amount of mold into the common living space of your home, creating an especially dangerous situation for you and your family. This is especially true if you or someone in your home is elderly, young, or an immunocompromised individual, although any level of exposure to certain types of mold can have an immediate impact on even the healthiest of people.

The first problem that must be addressed in anybasement is moisture. Mold is only a symptom of the greater problem, moisture intrusion. Moisture can enter a basement in many capacities. However, whatever the source of moisture, if the moisture problem is not solved, any damp basement will have mold at an elevated level.

Capillary suction is one of the most common causes of basement moisture intrusion and mold. Capillary suction occurs when moisture is drawn in through the ground outside the home as the heating and air conditioning pushes air into the living space of the home, thereby creating a vacuum in the basement. This phenomenon will also cause lime deposits on exposed block walls, also known as efflorescence. The mold will not grow on the block wall itself; instead it will grow on the dirt and other settled cellulose substrates (a food source for mold) that deposit on the block wall. In basements that are finished, this moisture will transfer to the lumber used to frame the walls and possibly even to the drywall itself. When drywall, otherwise known as gypsum wallboard, becomes wet, mold growth increases exponentially as gypsum wallboard is extremely rich in cellulose.

In order to stop water intrusion by means of capillary suction, proper waterproofing techniques must be applied to the block wall. Prior to applying any waterproofing materials, the wall must first be prepared for treatment. If this is a part

of a mold remediation, proper PPE (personal protective equipment) must be worn at all times inside the containment area. Any mold should be removed utilizing a professional mold remediator prior to applying waterproofing materials. After the mold has been cleaned, the wall must be prepared utilizing a wire brush to remove any excess mortar, dirt, dust, or efflorescence. Any existing paint should be removed using a sand blaster or wire brush (if you scrape or sand old paint, you may release lead dust. Lead is toxic. Please visit the EPA website on lead at http://www.epa.gov/lead.) If efflorescence is present, use muriatic acid, wash and scrub the block to remove the salt deposits. Next, utilize a waterproofing product such as Latex Drylock™ Masonry Waterproofer , following the manufacturer’s instructions. Dehumidification is recommended in basements with capillary suction problems.

Another cause of mold in basements is increased relative humidity due to stagnant air. Basements without the heating and air conditioning unitsinstalled may have elevated relative humidity levels as a result of a lack of air flow. In finished basements, mold will be very evident on the drywall in many areas. In unfinished basements, the appearance may be similar to that of capillary suction. One way to differentiate the two causes is to tape a 12 inch by 12 inch piece of aluminum foil tightly to the block wall by the edges and let sit for a few days.  If the wall side is wet, you have capillary suction, if the side facing out is wet, you have increased relative humidity causing moisture to condensate on cool surfaces. In basements with increased humidity levels, dehumidification is necessary.

Proper dehumidification will require a unit that extracts the correct amount of water from the air based on the size of the space being dehumidified. Many dehumidification manufactures have a formula to determine the size of unit with proper refrigerant to be installed in a given space. If the basement is finished and conditioned, consider using a unit that can be installed in-line with the HVAC system to dehumidify the air.

The most obvious and usually the most catastrophic cause of mold in a 

http://www.epa.gov/lead.) If efflorescence is present, use muriatic acid, wash and scrub the block to remove the salt deposits. Next, utilize a waterproofing product such as Latex Drylock™ Masonry Waterproofer , following the manufacturer’s instructions. Dehumidification is recommended in basements with capillary suction problems.

Another cause of mold in basements is increased relative humidity due to stagnant air. Basements without the heating and air conditioning unitsinstalled may have elevated relative humidity levels as a result of a lack of air flow. In finished basements, mold will be very evident on the drywall in many areas. In unfinished basements, the appearance may be similar to that of capillary suction. One way to differentiate the two causes is to tape a 12 inch by 12 inch piece of aluminum foil tightly to the block wall by the edges and let sit for a few days.  If the wall side is wet, you have capillary suction, if the side facing out is wet, you have increased relative humidity causing moisture to condensate on cool surfaces. In basements with increased humidity levels, dehumidification is necessary.

Proper dehumidification will require a unit that extracts the correct amount of water from the air based on the size of the space being dehumidified. Many dehumidification manufactures have a formula to determine the size of unit with proper refrigerant to be installed in a given space. If the basement is finished and conditioned, consider using a unit that can be installed in-line with the HVAC system to dehumidify the air.

The most obvious and usually the most catastrophic cause of mold in a 

to perform the proper testing to verify the level and type of mold present.

It is imperative that water be removed as quickly as possible from a basement after a severe leak or flood. Mold will begin growing in less than 48 hours. When a hot water heater is the source of the leak, the notorious “Black Mold” or Stachybotrys chartarum will likely be present. Proper drying techniques should be used when dealing with a leak or flood. The proper technique for drying is the drying triangle. This triangle utilizes heat, dehumidification, and air movement. Utilizing all three techniques will maximize any drying efforts. Many restoration and remediation companies will have the tools necessary to properly dry a given space. Once dry, the remediation of the mold may begin.

Mold remediation may be necessary in a leak or flood situation. Please understand that simply “killing” the mold is simply not enough to solve a mold problem. This is because there is no differentiation in allergenic characteristics of living and dead mold spores. In fact, even a dead mold spore can release a mycotoxin, which is the defensive mechanism of the mold spore that causes allergenic reactions in humans.

When dealing with any basement mold remediation, removal of damaged porous building materials is necessary. Porous building materials allow mold to embed itself and grow a mycelial root structure within the pores of the substrate. Porous substrates include drywall, insulation, wood paneling, carpet, carpet pads, OSB decking and low or high density particle board (commonly used to build kitchen and bathroom cabinets and countertops.) HEPA filtered negative air scrubbers and HEPA vacuums must be utilized in remediation to remove any settled or airborne spores from the environment. Any semi-porous substrates such as lumber used for framing or block walls may be cleaned using an anti-fungal biocide and HEPA vacuuming. Post remediation testing is crucial to determine whether the remediation was effective or not.

Basements are not a perfect science. Depending on what region of the country the basement is built, how high the water table is, what the grading 

outside the property looks like and a number of other factors can play into why a basement has mold and moisture problems. Mold is only the symptom of the greater problem that is moisture. After any water management plan and/or mold remediation is completed, it is highly recommended that a microbial inhibitor treatment be applied to prevent any mold from growing in the future. One product that is widely used because of its effectiveness and warranty is moldBLOCK™. moldBLOCK™ is made from aqueous potassium sorbate (the same ingredient used in the popular sugar substitute SPLENDA™ as well as many of the popular foods and drugs as a microbial inhibitor food preservative) formulated for the construction industry, making it the greenest and safest choice for people and pets. moldBLOCK™ has been ASTM (American Society of Testing and Materials) tested  and achieved a perfect score of 10 (ASTM 3273.) Best of all, moldBLOCK™ carries a full 20 year warranty on any substrate treated with moldBLOCK™ that is fully transferrable to a new homeowner. This means if mold ever grows on any substrate treated with moldBLOCK™, reapplication and remediation will be fully covered. moldBLOCK™ is only available from MoldStoppers™ and is applied by factory trained technicians.

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