The Hidden Dangers of Mold Growing on Your Crawl Space Soil

That fuzzy growth on your crawl space soil isn't just "dirt being dirt" – it's a potential health hazard silently affecting your home and family. Most homeowners don't realize that the perfect mold habitat exists right beneath their feet, with all five essential growth factors readily available.

Clay soil in your crawl space acts like a nutrient-rich refrigerator for mold, storing organic matter and vital minerals while holding moisture like a sponge – up to 55% by volume according to Cornell University research. Combined with adequate oxygen and the comfortable 60-80°F temperature your home maintains year-round, it's no wonder mold flourishes in this hidden environment. Within just 24-48 hours, mold begins its growth cycle, becoming visible within three weeks and continuously releasing spores and mycotoxins that can infiltrate your living space.

The health implications shouldn't be ignored. These microscopic invaders can trigger allergic reactions, exacerbate respiratory conditions, and gradually weaken your immune system through prolonged exposure. But before you grab a shovel to remove that moldy soil, stop! Disturbing contaminated soil triggers mold's defense mechanisms, sending spores airborne to colonize new areas of your home. Instead, professional remediation through proper waterproofing, encapsulation, and dehumidification creates an environment where mold simply cannot thrive. Your crawl space deserves professional attention – not just for your home's structural integrity, but for your family's long-term health and wellbeing. Ready to address that moldy soil properly? Check out my comprehensive guide to crawl space repair and protect what matters most.

Playlist mentioned in video: https://www.youtube.com/playlist?list=PLxsYiAum9ovwBw3L_-MD37h2rGoh4ho3p

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Episode Transcript

Speaker 0 (00:00):
Hey there, michael Church with Crawl Space Ninja.
Have you ever looked inside ofyour crawl space, looked down at
the dirt and saw mold growingon the soil of your crawl space?
Should you be worried aboutthis?
Is this dangerous or is it justdirt being dirt?
Today, we're going to answerthat question.
Is mold growing on the soil ofyour crawl space something to

(00:22):
panic about or just ignore andstick around to the end of the
video, I'm gonna share what youshould do if you find mold on
the soil of your crawl space.
Let's get into it.
First of all, you need tounderstand that mold needs
things to grow, not only in yourcrawl space, but in other parts
of your home.
Number one mold needs a foodsource, it needs moisture, it

(00:47):
has to have oxygen, as well assuitable temperature and, of
course, time.
If you give mold these fiveingredients, boom, it's a party
in the crawl space.
So let's take a look at eachone of these individually and
how soil relates to each one ofthese as well.
So is the dirt under your crawlspace a smorgasbord for mold?

(01:07):
Well, surprisingly, yes, it is,especially those clay-rich
soils that many homes built oncrawl spaces have.
But what's interesting is,according to soil scientists,
mold doesn't grow directly onthe clay.
But here's the twist Clay holdsnutrients and organic matter

(01:29):
that mold loves.
Think of clay as a refrigerator.
It stores the leftovers formolds to snack on.
Plus, clay soils have a highcation exchange capacity, or CEC
that's a fancy way to say that.
They attract the vitalnutrients that mold needs.
These nutrients include calcium, potassium and magnesium, all

(01:53):
of which support microbialgrowth.
And, yes, mold is a microbial.
Okay, so we determined that soilis a food source, but is soil
wet?
You better believe it,especially clay soil.
It's like a sponge.
Unlike sandy soil that drainsrapidly, clay soil holds water
for days or even weeks at a time.

(02:15):
According to Cornell University, clay soil can hold up to 55%
moisture by volume.
That's like walking on a wetsponge every time you're under
your house.
In short, if you have clay soilin your crawl space, you have
moisture in your crawl space,which is a green light for mold
to grow.
So the third ingredient isoxygen.

(02:36):
Does soil have oxygen, you bet.
Unless it's completelywaterlogged or compacted, the
air between soil particlescontains oxygen, nitrogen and
carbon dioxide, all of which islike the air around us, and
scientists say that moldbreathes as well, well sort of.
It absorbs the oxygen in orderto help it grow.

(02:59):
And not only does that oxygenhelp it grow, it helps it spread
to other areas of the home.
But what about temperature?
Mold does need the righttemperature to grow and most
crawl spaces hit that sweet spotall year long.
Mold typically thrives intemperatures between 60 degrees
Fahrenheit and 80 degreesFahrenheit, but some molds can

(03:20):
survive in freezing temperatures, like in the Arctic and
Antarctic regions, as well asvery high temperatures, like in
the Arctic and Antarctic regions, as well as very high
temperatures, like in jungleregions.
In cold weather, mold sporescan or may go dormant, but that
doesn't mean they're dead.
They're just sitting therewaiting for the temperature to
rise and for that moisturethat's trapped in that clay soil

(03:44):
, along with all the nutrients,so that it can thrive and
survive.
As I mentioned before, thereare even Arctic molds and desert
molds, so molds can pretty muchthrive anywhere in the world.
So don't let the seasons foolyou.
Just because it's winteroutside doesn't mean that mold
isn't growing in that crawlspace, because I guarantee you

(04:05):
the heat from your HVAC systemis keeping that crawl space warm
enough for that mold to spreadand grow.
Lastly, is time.
This one usually does not comeup when you look at what does it
take for mold to grow, but Iwanted to throw one.
Usually does not come up whenyou look at what does it take
for mold to grow, but I wantedto throw this one in there just
to give you a little bit ofeducation of how long it takes
for you to visibly see moldgrowing in the soil or perhaps

(04:28):
on the joists of the crawl space.
Mold can start growing in aslittle as 24 to 48 hours.
Usually this would occur aftera water event or high humidity,
but, as we mentioned before,soil traps a lot of water.
It could take anywhere between18 to 21 days for the mold to
become visible.

(04:48):
This is what's called thefruiting body.
It's sort of like if you'rewalking in the woods and you see
a mushroom growing on theground.
Well, the mold was growing inthe soil before the mushroom
showed up.
So if it takes 24 to 48 hoursfor mold to get started, you
could possibly see it within 3to 12 days, but most scientists

(05:18):
agree it takes between 18 to 21days for mold to become visible.
And don't forget mold coloniescan spread extensively and
become more noticeable the moremoist the crawl space is.
Factors like types of mold, thesurface it's growing on and the
surrounding temperature andhumidity can also influence the
exact time it takes for mold tobecome visible.
Now let's get into the healthquestion.
Is mold on dirt actuallydangerous?

(05:38):
The answer is potentially yes.
You see, mold spores can goairborne, especially from the
dirt in a crawl space.
If the crawl space soil isn'tsealed away from the rest of the
crawl space, you might not evensee the spores.
As I mentioned, most moldspores are microscopic, but that
doesn't mean they're notlooking for a new place to grow,

(06:01):
like inside the HVAC system oron the joist of the crawl space,
or maybe even in your livingspace.
Some molds can cause allergies,while depending on the immune
system of the person, it couldbe more extreme Like COPD or
even asthma can occur in peoplewith weaker immune systems.
And let's not forget themycotoxins.

(06:22):
It's sort of like anoff-gassing of the mold, and the
longer you're exposed to mold,the more attack it does on your
immune system and the weakeryour immune system becomes.
So if you know that you havemold in your crawl space or in
your living space, you shouldaddress it immediately.
Don't wait and if you need helpwith that, of course Crawl

(06:42):
Space Ninja can help.
Speaking of help, I want totake time to introduce you to my
book Crawl Space Repair MythsBusted.
Whether you have a crawl space,basement or you live on a slab
house, this book has a lot ofgreat information about mold and
moisture.
So if you want to be armed withgood information to protect
yourself from making a baddecision, I recommend you pick

(07:05):
up crawl space repair mythsbusted, available on amazon in
both the printed and audibleformats.
Okay, so you might wonderingshould you remove that moldy
soil?
Honestly, that's a pretty badidea and here's why Mold has a
natural defense system and ifyou go in there and start
digging out that soil, you'rejust going to cause that mold to

(07:27):
enter fight or flight mode, andtypically it's going to flight,
which means it's going to gosomewhere else and land and it's
going to try to find moistureeither on the joist, the
subfloor behind the insulationinside the HVAC system, or make
its way through the penetrationsin your subfloor right into

(07:47):
your living space.
So I don't recommend removingthe soil because even when you
do remove the soil and you putnew soil back in, the old soil
is going to expose mold to thenew soil.
So what should you do?
What we always recommend is aninterior waterproofing system
with sump pump, along withencapsulation and

(08:09):
dehumidification, and I knowwhat you're thinking.
Wait a minute, michael.
You said not to disturb thesoil.
Well, as we are digging thatsoil out, we're going to have a
fan blowing the to disturb thesoil.
Well, as we are digging thatsoil out, we're going to have a
fan blowing the air out, so thatway, if any of that mold
trapped in the soil becomesairborne, it has a place for it
to go outside of the crawl spaceand keep it from getting inside
of the home.
But installing that interiorFrench drain and sump pump

(08:32):
system is going to minimize theamount of moisture in the soil.
And then you lay the plasticdown over that soil to help
separate the soil from the airof the living space.
You keep the humidity down withyour dehumidifier and it should
keep the mold from growing andspreading inside the crawl space
.
So, in summary, mold growing onthe crawl space dirt could be a

(08:54):
big deal and you shouldn'tignore it, but you shouldn't go
in there and start digging thedirt out.
As a matter of fact, if youwant to learn more about what to
do.
I'm going to put a playlist ofthe crawlspace repair challenge
that we did.
That covers everything from theinspection to the final product
, so make sure you check outthat playlist and I'm Michael

(09:14):
Church with Crawlspace Ninja.
Hope you make it a happy andblessed day and we'll see you
later.