Mold In Crawl Spaces: 5 Things to Know

by | May 31, 2021 | Mold Damage, Mold Repair, Restoration, Water Damage, Water Damage Repairs, Wood | 0 comments

Houses with crawl spaces have several advantages. For example, a crawl space foundation is suitable for flood-prone areas and provides easy access to the plumbing, wiring, and HVAC systems. However, some dangers could be lurking within your crawl space. When was the last time you inspected your crawl space?

A place likely to be not often visited, crawl spaces can often be tidy, cluttered, and dusty instantly. The moisture levels and the dark atmosphere in such areas can provide the perfect thriving environment for rodents, cockroaches, spiders, and others. Mold growth has been one of the biggest concerns associated with crawl spaces.

Signs of mold in a crawlspace 

You don’t necessarily need to inspect a crawl space to diagnose crawlspace mold; you just have to heed to the following signs:

When the heating system is operational, the air flows upward and creates a vacuum that pulls the air from the crawlspaces (“stack effect”). If your crawlspace is moldy, the air pulled up smells musty, and you could start exhibiting the symptoms, including itchy eyes, difficulty breathing.

If unattended for long, Mold crawlspaces start to rot and decay; this leads to the sagging, buckling, and the floor immediately above. Doors jamming and discoloration on the floor surface could be the symptom of moldy crawlspaces.

The direct signs of crawlspace mold include signs of water damage or discoloration on the wood, visibly mold growth, and a musty smell.


The following three types of mold are commonly found in crawlspaces:

Black mold: with a grayish or greenish appearance, black mold is a deadly and common mold type found in crawlspaces. Both strains of black mold (Stachybotrys atra and Stachybotrys chartarum) can release mycotoxins capable of triggering severe allergic reactions.

White mold: with a powdery fungus appearance, white mold usually thrives on the soil surface and wooden joists. This mold type usually takes up the color of the surface it has infected; common colors are white, green, or grey. 

This mold can thrive quickly as long as they have consistent food sources such as wood products or any other surface made of starch and sugar. While not dangerous as black mold, white mold can release health-affecting toxins.  

Yellow mold: with a yellowish appearance, yellow mold thrives on damp surfaces, especially soil and forest floor. Yellow mold is known to create respiratory issues.

Effects of crawlspace mold

The effects of crawlspace mold can range from health concerns to a decline in home value. Some major problems are:

  • Allergy systems including itchy eyes, wheezing, nasal stuffiness, sore throat, skin irritation, and relentless cough.
  • Musty smell throughout the house
  • Structural damage: the sagging and buckling of mold affected floor could lead to structural damage
  • People usually stray away from mold-infested houses in the market; even clean properties with a history of mold infestation are undervalued
  • Toxic Mold Syndrome is another serious concern that arises due to continuous exposure to a particular mold type; some symptoms include: depression, memory loss, insomnia, loss of appetite, and anxiety


Certain things can make your crawlspace vulnerable to mold growth. Crawlspaces are usually dark and moist and offer the perfect platform for mold colonies to thrive. Moisture is the most crucial requirement for mold growth, and there are different ways via which moisture can find its way to your crawlspace.

Penetrating damp is a means such as leaky plumbing system, mechanical failures that help moisture find its way to the crawlspace.

Rising damp is the process where moisture is surfaced from the ground. Crawlspaces not encapsulated or protected via vapor barriers are vulnerable to rising damp.

Condensation is moisture formation due to the difference in air temperature between the inside and outside.

Prevention & elimination of crawlspace mold 

Keeping the mold space encapsulated and regulating the moisture levels within are the main crawlspace mold preventive tips.  

However, DIY or most industrial mold removal methods hardly provide long-term solutions to crawlspace mold. Mold can re-grow in 24 to 48 hours if a permanent fix to the favorable condition to mold growth is eliminated. Getting your crawlspace health checked with the help of a crawlspace mold removal specialist is a smart move. A professional mold remediation company should use quick and effective remediation services with onsite evaluations and written estimates.


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