Household Mold & Moisture

Household mold is a very common issue for every homeowner. If indoor moisture is not controlled, then mold will grow.

How can mold grow in my home?

Molds are part of the natural environment. Outdoors, molds play a part in nature by breaking down dead organic matter such as fallen leaves and dead trees, but indoors, mold growth should be avoided. Molds reproduce by means of tiny spores; the spores are invisible to the naked eye and float through outdoor and indoor air. Mold may begin growing indoors when mold spores land on surfaces that are wet. There are many types of mold, and none of them will grow without water or moisture.

Generally, within 48 hours after getting wet, invisible mold growth has started on wet woods and paper-backed products such as drywall. After about four days, mold growth on surfaces is visible in the form of discoloration, frequently green, gray, brown or black, but also white and other colors.

Can mold cause health problems?

Molds are usually not a problem indoors, unless mold spores land on a wet or damp spot and begin growing, therefore creating excess mold spores. Molds have the potential to cause health problems when in excess. Molds produce allergens (substances that can cause allergic reactions), irritants, and in some cases, potentially toxic substances (mycotoxins).

How do I prevent the growth of mold?

It is impossible to get rid of all mold and mold spores indoors; some mold spores will be found floating through the air and in house dust. The mold spores will not grow if moisture is not present. Indoor mold growth can and should be prevented or controlled by controlling moisture indoors.

The increasing incidence of household mold problems in residential construction has been attributed to many different factors including less air exchange between the treated inside air and unconditioned outside air, poor Heating, Ventilation, Air Conditioning, (HVAC) planning, the changing nature of building materials, poorer site location as prime building sites become more scarce, and a host of other potential causes. It is often claimed that through simply controlling the relative humidity and allowing for sufficient air exchange, mold incidence can be completely controlled. The prevailing wisdom is that when relative humidity is held to below 50%, mold will not even be an issue.

During the building process, there are several times when high moisture conditions exist. During the concrete curing times (foundation walls, concrete slabs), during the framing process after rains and after mudding of the drywall. It is extremely critical that sufficient time is permitted to allow the materials to properly dry or additional drying methods are used, otherwise you could be trapping moisture inside the materials or building cavities (inside walls), which can promote mold growth.

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Building Tip

"Always build a roof/porch over an exterior door to prevent water leakage. Most exterior doors will leak when hit by direct rain."

Front Porch


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