Why is Mold Suddenly So Common?
If it feels like theres suddenly a big emphasis on mold and health, you're not wrong.
Mold has actually become more and more of an issue in the past 20 or so years because of a combination of factors. Below are some of the biggest reasons why mold is suddenly so talked about:
Drywall is now the main building material in homes
Older homes were typically made of brick, plaster , stone, and old-growth timber (meaing very dense wood). However, nearly all homes use drywall now because it's cheaper, easier to install. But it's also the perfect material for mold to thrive. Here's why:
Drywall is an organic material, making it a perfect food source for mold
Drywall absorbs and traps moisture behind in wall cavities
Drywall often doesn't look damaged until the mold problem has gotten severe
All this means that even when you have a small leak, there's a strong chance that it will start growing mold. And unfortunately, small leaks happen all the time with the current way homes are built
Homes have more water issues now than before
Objectively, homes built today are built very well. However, fast building, cost cutting, and regulations oftentimes leads to homes having serious issues despite being brand new.
For example, below is a photo of a semi-new home we inspected that has a disconnected bathroom exhaust fan causing moist air to vent into the attic where it couldn't escape.
It's these kinds of problems that cause mold regardless of how dry the climate you live in is.
Lack of Ventilation in Newer Homes
Homes built since the 1970s are significantly more airtight than older homes. This shift happened for energy efficiency, but it also changed how buildings handle moisture.
Older homes tended to leaked air, which allowed moisture to escape before it became a problem, but modern homes are much more tightly sealed. Although controlling the air inside is objectively more efficient, it also means water can get trapped too. This leads to the following:
Water from a leak or rain or bad ventilation a tightly sealed space in the home and has no way to get out (such as behind a wall or in a attic)
Mold spores begin to use this added moisture to spread and grow
Mold begins to spread until it's a big enough problem to notice
Combined Effect
Mold-friendly building materials, cost cutting, and airtight construction create
conditions where mold can take hold quickly once a home takes on water. In fact, 47% of homes have a moisture problem big enough to grow mold.
A home doesn’t need major water damage for this to apply; a slow leak or a single water event is often enough.
So do I need to get my home tested?
No. To be clear, we don't suggest that every single home has mold and should be tested for it – that would be scare tactics. But in some cases, we strongly suggest testing.
The point of this article is to help homeowners understand that if they notice a musty smell, a family member is getting sick, or something seems out of the ordinary, then mold is a real possibility. At that point, and really only at that point, is it worth getting a mold test.
When to test for mold
Mold can begin growing within 24 to 48 hours of a water event, so any leak or spill should be addressed quickly. Here's some other reasons to test.
A musty smell is a signal worth investigating, even without visible mold
You have had a leak in the past and never tested for mold afterwards
You can see visible mold to a small extent
Someone is getting sick with unexplained symptoms
You have underlying health conditions and want to rule out the possibility of mold
Common questions about mold being more common now:
Here's some questions we get a lot while doing mold testing/inspections.
Is mold a new problem, or has it always been around?
Mold isn’t new . It’s a natural part of the environment and always has been. What’s changed is how often it becomes a problem inside homes, largely due to the building materials and construction methods used since the mid-1900s.
Does Utah’s dry climate protect homes from mold?
Not to the extent most people assume. Utah’s dry air affects the outdoor environment, but it has little to no effect on a wall cavity once water gets trapped inside it. Homes here can and do develop hidden mold problems just like anywhere else.
Why is drywall more prone to mold than older building materials like plaster or brick?
Drywall is made with paper facing, which is an organic material mold can feed on directly. Older materials like brick, stone, and plaster are denser and don’t offer mold the same food source, which made older homes more naturally resistant.
If my home had a leak that appeared to dry out fine, could I still have a mold problem?
Yes. Surfaces can dry out while moisture remains trapped inside
a wall cavity , especially in modern, tightly sealed construction. Even if mold is dead or dried out, it can still cause major health affects. That's why we search for the root cause of the mold issue and even look for dead mold.
How quickly can mold start growing after a water event?
Mold can begin developing within 24 to 48 hours of water exposure. That short window is why addressing leaks and spills quickly matters as much as fixing the source of the water itself.
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