Crawl Space Mold and Summer Heat

Because of something called the stack effect, having open crawl space vents or a dirt crawl space is much worse than just a moisture problem. In fact, more than 50 percent of the air you’re breathing on the first floor comes from the crawl space. And because of the stack effect, you might be breathing air that holds pieces of whatever’s in your crawl space right now. Here’s how the stack effect works.

An Entrance and an Exit

First, the stack effect requires an entrance at the bottom and an exit at the top for air. The exit is present in pretty much everyone’s home; it may be due to opening an upper-level door or it might be the rafters in your attic. The entrance, however, isn’t present in all homes. If you have open vents or a dirt crawl space, however, air can come through either of those. 

The basic principle of the stack effect is that air comes through your open crawl space vents or dirt crawl space, warms up, and rises through your home. As it rises from the crawl space into the living space, it takes a variety of things from the crawl space into the rest of the home. That’s one of the reasons it’s so disconcerting.

Warm Air Rises

This is a basic concept in chemistry. Essentially, when air warms up, it becomes less dense than the same mass of cool air. When warm air and cool air are existing side by side, the warm air wants to move on top of the cool air, which takes the warm air’s place. When you apply this concept to the stack effect, it’s easy to see why it messes up your home.

When the air enters your crawl space, either by the crawl space vents or by the dirt floor, it may either be warmer or cooler than the rest of the air. If it’s warmer, as it probably is during the summer, it’ll immediately start rising to the top. If it’s cooler, it’ll start warming up because of all the warmer air around it. Either way, the air will rise to the top of the crawl space.

Particles Cycling Through Your Home

One of the reasons this is such a big deal is the fact that many of the particles in an unencapsulated crawl space are small enough to become airborne. That’s enough for many of them to start cycling through your home. This means they’ve gone from the ground in your crawl space to floating around in the air in your living space.

These particles can be very dangerous, especially if you have allergies or respiratory problems. They become even more dangerous if you have a wet crawl space because the particles in a wet crawl space tend to have more issues than the particles in a dry crawl space. If you have open crawl space vents, you almost definitely have a wet crawl space, so it’s definitely a concern.

How Big Can a Particle Be?

Some people wonder how big a particle can be before it’s no longer able to be airborne. The truth is that the weight of a particle matters much more than the size. Think about it: A large feather can often become airborne, but a very small marble can’t. However, especially in crawl spaces, the particles that end up becoming airborne are almost always very small, typically small enough to be almost invisible.

Most of the time, particles consist of small specks of dirt, bacteria, and mold spores. Occasionally, you may find something like a dust mite, which isn’t big enough to see with the naked eye but can still wreak havoc on your living situation. Think about all the things coming up from your crawl space and consider that even small particles can be dangerous.

Many of the problems in the crawl space, including problems you can attribute to the stack effect, have to do with moisture in your crawl space. So where does all that moisture come from? These are the most common sources of moisture in a crawl space.

Open Crawl Space Vents

Far and away the most common source of crawl space moisture is open crawl space vents. Unfortunately, it’s almost unavoidable to experience high levels of crawl space moisture if you have crawl space vents. Most homes with open crawl space vents have very high levels of moisture, which can easily lead to mold, mildew, high electric bills, and a variety of other potential concerns.

Back in the day, people used to believe open crawl space vents were actually better at avoiding moisture. The idea was that the open vents would “air out” the crawl space, thus bringing out moisture. However, the fact is that crawl space vents introduce air of different temperatures to each other, and that’s a recipe for condensation and other disasters.

Dirt Crawl Spaces

Many homes have dirt crawl spaces because they’re cheaper than concrete crawl spaces. However, they also have many more issues. One of the biggest problems dirt crawl spaces tend to introduce into a home is the problem of significant crawl space moisture.

Even if your dirt crawl space looks dry from the top, you can never be fully sure whether it’s hiding a huge amount of moisture. Moisture in the earth stretches down a substantial way, which means it can hide away until you least expect it. After days, weeks, or months, your crawl space will be wet for seemingly no reason.

Leaks and Plumbing Problems

It’s also possible, if not likely, to have crawl space moisture problems because you’re experiencing some sort of leak. Most of the time, this happens because homeowners haven’t had a look down at their crawl space, because it’s often easy to notice as soon as you look at the crawl space as a whole.

These leaks and plumbing problems cause two problems. Obviously, the leaks and plumbing problems are a threat to your crawl space’s health. It’s important to fix them to make your crawl space healthier. However, this is also a problem because you’re likely to spend much more on your water bill, and because wasting water is never a good thing.

How can you stop crawl space moisture? The answer is simple. You need to encapsulate your crawl space. This can sound like a very daunting and difficult process, but if you put your trust in a JES crawl space repair expert, dealing with moisture can be easy. Here’s how a JES crawl space expert will encapsulate your space.

Step 1: Remove Existing Water

The first step to crawl space encapsulation is removing any existing standing water. Obviously, you won’t be able to start work on avoiding future standing groundwater unless you’re dealing with a generally clean crawl space. There are a number of methods you can use to remove the existing water in your crawl space, making it much easier for you to do the next steps.

One of the most common methods of removing existing standing water in a crawl space is with a simple sump pump. Sump pumps are great for removing standing water because they take the water – usually collected by an interior drainage system – and pump it out entirely.

Step 2: Close Crawl Space Vents

Next, it’s important to close all crawl space vents. Now that you know you don’t have any standing water in your crawl space, don’t you want to make sure you don’t end up with more? Closing the crawl space vents for good can help you make sure you don’t end up with serious moisture problems in your crawl space in the future, especially if those moisture problems are related to floods and rain.

Typically, closing crawl space vents is generally a pretty simple process. You can use crawl space vent covers, which go on top of your crawl space vents, to make sure no air or moisture can come inside. A JES crawl space expert can give you more insight into how they may be able to handle the vent-closing process.

Step 3: Install a High-Quality Vapor Barrier

The next step is to install a vapor barrier that’s thick enough to hold up to repeated crawl space expeditions. Although the minimum requirement is typically a 6-mil crawl space barrier, you should never opt for that over a thicker one, especially when you’re trying to encapsulate your crawl space. This can just make the crawl space barrier tear over time.

Instead, it’s important to opt for the most powerful vapor barrier available. JES only uses the 20-mil CrawlSeal™ crawl space vapor barrier. The 20-mil barrier is more than three times as thick as most building residential codes require, and that makes it perfect if you’re trying to keep your crawl space from having any additional damage. This includes damage due to moisture and damage that can occur to the vapor barrier itself.

Step 4: Add a Crawl Space Dehumidifier

The last step should be adding a crawl space dehumidifier if necessary. The crawl space dehumidifier is an important part of encapsulation because it helps regulate the moisture levels in the crawl space. Even after encapsulation, it might be an important option.

If you do use a one, it’s important to consult a crawl space repair expert so you can understand your unique needs. Plus, you need a crawl space dehumidifier that’s as energy efficient as possible. When you consult a crawl space repair expert from JES, you’ll get an answer to these questions and any other questions you might have about the encapsulation process.