Mold: Common Mold Sources Found in Your Home

What is Mold?

Mold is a naturally occurring fungus found in the environment. To have fungal growth occur, two things are necessary: Moisture and a Food Source.

Moisture occurrence has many possible causes, including Structural and Plumbing leaks, and high Humidity Levels.

Food sources include “organic” matter found in structural building materials and contents, such as paper products, gypsum board, wood, materials containing natural fibers, paint, wallpaper, furniture, carpet, and upholstery to name a few.

Mold is found in all climates around the world, from the extremely hot to the extremely cold. There are thousands of fungi and molds that have been identified in the world. There are over 100 types commonly found and identified in Tennessee alone! The spores produced by these molds are spread natural through the air. When indoor mold growth exceeds outdoor levels, it is considered to be a potential “mold problem”.

Helpful Tips
Commonly found mold sources (both indoor and outdoor) are areas to pay attention to in order to aid in the prevention of mold growth. Remember, mold needs moisture to live and grow.




Indoor Sources:

  • Plumbing leaks and failures: toilets, drain lines, supply lines, vent stacks that penetrate through attics and roofs.
  • Appliances: Improper installation or failures of; dishwashers, ice makers, refrigerators, and clothes washers.


importantImproperly ducted clothes dryers are a common problem we find routinely on initial inspections. Dryers ducted directly into a crawlspace or attic or ones that have compromised exhaust lines can cause immediate & excessive mold growth.



  • Ventilation: poorly vented bathroom and kitchen areas as can poorly vented crawlspace or attic areas, can lead to mold growth caused by condensation issues from inadequate ventilation.
  • HVAC: Keeping your AC unit, split units (one part inside, one outside) and package units (all one piece), in good working order is not just good for your comfort level, but broken or leaking condensation drains can cause visible mold growth within 48-72 hours if left unattended. Also, clogged “A coils” in air conditioning season can create high Relative Humidity.


Exterior Sources:

  • Roof leaks: Roof leaks allow moisture to enter into your home directly; they may be difficult to find. Check around flushing, vent stacks, ridges, valleys, and skylights. These are common sources of water or moisture intrusion. If you have an attic access, you may want to inspect the back side of the roof decking to look for dark or water stained areas.
  • Chimney caps: cracked or deteriorated chimney caps are another place for moisture to enter your home and cause mold growth.
  • Mortar voids: voids around window lintels and brick molds can allow moisture to penetrate the wall cavity on exterior walls causing mold growth. These leaks are hard to see until the interior drywall becomes affected. We check these areas for water intrusion with Thermal Imaging Cameras and wall cavity moisture detection.
  • Undersized or Blocked Gutters: inadequate gutter sizes or debris blocked gutters can cause penetration to the fascia and soffit areas. It can also cause water to overflow and collect in areas around the foundation penetrating the block and into the crawlspace.
  • Hose Bibs: if any hose bibs have been damaged due to freezing, this needs to be addressed as soon as possible. They may not break right away, even after they are thawed out. We have seen many times when homeowners hook a hose up to these bibs in the spring and a flood has occurred due to their condition. If you have water running in the walls or hear a “roar” when the valve is turned on, shut off the valve immediately and have it assess by a professional.
  • Mulch Beds: Adding to the top layer of a mulch bed year after year without removing the old mulch can cause moisture build up over time. Multiple layers act as a sponge and hold moisture that can affect foundation walls and crawlspaces.
  • Irrigation/Sprinkler Systems: sprinklers, jets, and heads that are installed too close to or facing exterior surfaces such as brick veneer, siding, stucco, or foundation block can cause water damage and mold growth on or behind these surfaces.
  • Geography: Drainage and Terrain issues allowing ground water to infiltrate foundation walls and crawlspaces may require specialized drainage diversions including trench drains, surface drains, French drains, or curtain style drainage.

In short, it’s always a good idea to get familiar with, and be aware of, the physical and mechanical aspects of your home or business. Being aware of the areas discussed in this post can save you time, money, and aggravation. Please call us if we can help you sort out any concerns you may have regarding water intrusion or mold growth.

‘Til next time!

Dan Richey

Richey Restoration, Inc.