The Complete Guide
to Crawl Space Encapsulation, Waterproofing & Repair (2025)
Everything you Need to Know
Your crawl space plays a critical role in your home’s health and comfort. It supports your structure, affects your indoor air quality, and can even be used for storage. But if your crawl space is damp, musty, or damaged, it can threaten your entire home.
That’s where crawl space waterproofing, encapsulation, and repair come in.
We know dealing with crawl space issues can feel overwhelming. That’s why we’ve created this complete guide—to answer your biggest questions and show you how to keep your crawl space clean, dry, and protected for the long haul.
Chapter 1: Understanding Your Crawl Space
Crawl Spaces Get a Bad Rap
They’re often viewed as dirty, cold and even creepy. For many NJ homeowners, their crawl spaces don’t play a role in making their homes feel cozier. Therefore, they don’t believe that their crawl spaces need to be inspected or thought about all that much.
But this is the wrong way to look at your crawl space.
You see, when your crawl space is properly shielded and protected from the elements, it can provide additional storage space and make your home feel comfier. But there’s more than just functionality and comfort at stake. Your crawl space is the foundation of your home. It needs to be properly treated and maintained to ensure your home remains safe and structurally sound. Crawl space waterproofing and crawl space encapsulation are the best ways to secure your crawl space and protect the health, safety and comfort of everyone in your home.
We’ll talk more about waterproofing and encapsulating later in the chapter. But first, we want to provide a brief overview of why your home has a crawl space and what it’s designed to provide (and not provide).
The Foundation Family: Basements, Crawl Spaces & Concrete Slabs
Nearly every home in New Jersey has one of the following foundation types: a basement foundation, a crawl space foundation or a concrete slab foundation.
If we were to look at these types of foundations as three siblings, the first would be the basement foundation. This is the most mature member of the family. It’s the tallest and provides the most amount of space. Basement foundations are common in NJ, especially in older homes.
They’re ideal for climates like ours where the winters are very cold and the summers are very hot. Basements are similar to crawl spaces in the sense that both are susceptible to water damage, mold growth, pest infestations and high humidity levels. This is why it’s important to waterproof the basement, regardless of whether the basement is finished or not.
The middle child is what you have, a crawl space foundation. Crawl spaces can be anywhere from 1 to 4 feet high. Unlike basements, crawl spaces do not provide additional living space and will never become your new indoor gym, home office, extra bedroom, etc.
Crawl spaces are common and beneficial in NJ because this type of foundation raises the home above ground level. Homes near the shoreline, rivers or any sort of waterway will want at least a crawl space foundation so the home stays above the water table, which can be very high in New Jersey.
A Clean Basement Means More Usable Space
A crawl space also frees up living space because you can use this area to store your water heater, HVAC system and other home equipment. It’s also common for the electrical wiring to run under the crawl space, providing easier access for electricians.. In addition to saving space, crawl spaces and basements make it easier to inspect for termites. If your crawl space is waterproofed and encapsulated (in other words, completely sealed off from the outside), you can also use this space to store personal belongings.
Lastly, we have the youngest sibling: the slab foundation. This type of foundation consists of a concrete slab that rests right above ground level. Naturally, this type of foundation is not ideal for areas with a high water table. You’ll recall how after Hurricane Sandy, most of the homes along the Jersey Shore were raised to avoid future flooding damage.
The benefit of a slab foundation is that it’s the most simple and cost-effective of the three. However, preventive maintenance is especially important with slab foundations because traditional waterproofing methods cannot be used in these types of homes. Therefore, it’s essential to ensure the home has proper grading and properly working gutters to help prevent water intrusion.
What Problems Can Occur With Crawl Space Foundations?
We just established how crawl space foundations are the middle child of the Foundation Family. If you’re familiar with “middle-child syndrome,” you know that part of this hypothetical idea involves the middle child wanting attention. (This guide was written by a proud middle child, for what it’s worth).
Just as the middle child might feel overlooked, your crawl space can feel overlooked, too. But this is the worst thing you can do as a homeowner. If you neglect your crawl space and deprive it of the care it needs, you’re bound to experience problems down the road. The most common problems associated with crawl spaces include:
- Water seepage
- High humidity
- Pest infestations
- Mold growth
- High energy bills
- Wood rot
- Foundation damage
- Poor indoor air quality
We’ll dive deeper into each of these issues in subsequent chapters, but the most important thing to know is that your crawl space requires more attention than what meets the eye. The contractor that built your home added the crawl space for foundational purposes. Construction companies do just that—construct homes.
They do not put the tools and systems in place to fully seal off your crawl space from the surrounding elements. If they did, every crawl space that’s built would be waterproofed and encapsulated from the start. In order to prevent future problems such as wood rot and structural damage, it’s important to invest in preventive measures. In this case, crawl space waterproofing and encapsulation.
A Solution to Basement Water Problems
Reach out to us for a free, no-obligation basement inspection and estimate.
What’s the Difference Between Crawl Space Waterproofing & Crawl Space Encapsulation?
As mentioned previously, the two best ways to protect your crawl space and prevent future issues are crawl space waterproofing and crawl space encapsulation. Both of these measures are designed to keep your crawl space dry and damage-free.
The first course of action is crawl space waterproofing. This involves removing existing water and humidity that can result in mold growth, structural damage, pest infestations and more. We’ll install a French drain along the perimeter of your crawl space.
The system will be graded to ensure the water drains to the sump basin containing the sump pump. From there, the water will be pumped out of your home and through the underground exterior discharge pipe. All of the water will be discharged into the street or at least 15 feet away from your home.
While it’s important to target the water first, we need to treat the remaining humidity. We’ll also install a dehumidifier in your crawl space to remove excess moisture from the air and keep the humidity level at 50% or under. Anything higher will create an environment that’s conducive to mold growth, wood rot and more.
Moving to Crawl Space Encapsulation After
Crawl Space Waterproofing
Once the water is removed and the humidity is under control, crawl space encapsulation is the shield that prevents history from repeating itself. We’ll discuss this more in-depth later, but the most important thing to know about crawl space encapsulation is that it’s the process of sealing off your crawl space from the outdoor air and humidity.
It involves closing up any crawl space vents, installing a sealable crawl space door and installing thick, impermeable vinyl liners/vapor barrier on the crawl space floor and walls.
If you see a crawl space that’s covered in white liners instead of the typical dirt floor and cinder block walls, then you know the homeowner encapsulated the crawl space. In other words, they’ve spared themselves from the ongoing costs, frustrations and discomforts that come with a neglected, poorly maintained crawl space.
In addition to waterproofing and encapsulating your crawl space, insulation will provide additional benefits. If your HVAC system and water heater are located in the crawl space, extreme temperatures in the winter and summer will force your equipment to overwork itself, resulting in higher energy bills.
Do You Need to Insulate Your Crawl Space?
Yes, by insulating your crawl space, the temperature will be much more regulated throughout the year. Not only will your energy bills go down, but your home will also feel more comfortable. This is especially true during the winter when a freezing crawl space makes your floors feel colder. Insulating the crawl space is a great idea in New Jersey to help combat our frigid winters and scorching summers.
If there’s one thing we hope you’ll take away from this chapter, it’s the fact that your crawl space matters. Just because you don’t go in it very often or use it for all that much, this doesn’t mean it can be overlooked. Your crawl space creates the foundation for your entire home.
By taking proper care of this small little space, you can ensure the rest of your NJ home will remain as secure, healthy and comfortable as possible for the long term.
Still Have Questions?
Give us a call today to speak with one of our basement waterproofing experts.
Chapter 2: How Water & Humidity Affect Your Crawl Space
New Jersey & Crawl Space Water
Here in New Jersey, we’re fortunate to live near rivers, lakes and, of course, the Jersey Shore. But our close proximity to the coast means higher humidity levels across the state. Compared to other parts of the country, New Jersey is definitely more humid.
Humidity measures the amount of water vapor in the air. If you’ve lived in New Jersey long enough, you can walk outside on any given day and immediately tell whether the humidity is higher or lower. When it’s higher, everything feels sticky. It’s more difficult to exercise and breathe, and you might experience other discomforts such as allergies and headaches. Humidity isn’t something you can necessarily see—but it’s something you can certainly feel.
As much as we don’t enjoy extreme humidity, neither does your crawl space. Many people believe their crawl space is A-OK as long as there’s no standing water inside. Unfortunately, this isn’t true. In this chapter, we’re going to cover the two main culprits of crawl space issues and the various problems that occur when crawl spaces are not kept dry.
Culprit #1 Water In Your Crawl Space
There are a number of different ways water can enter your crawl space. While you can’t control Mother Nature and the amount of water that comes your way due to melting snow, heavy rainfall or other natural events, you can certainly protect your crawl space from flooding and water-related damage.
If you notice water in your crawl space, it’s likely due to one or a combination of the following issues:
- Cracks in the foundation walls
- Water seepage between the footing and foundation walls
- Improper grading
- Sump pump issues
- Clogged or ineffective gutters and downspouts
- Plumbing leaks, burst pipes or sewage backup
- Condensation buildup due to high humidity
- Open crawl space vents
- Leaky window wells
- Excessive rainfall
We’ll discuss these issues more in-depth in the next chapter. But no matter what’s causing water to enter your crawl space, it’s important to address the issue(s) immediately to prevent costly problems down the road.
Inspect your crawl space periodically and check for signs of flooding such as horizontal water lines on the walls and piers, wet soil, etc. Because there are so many different ways water can enter the crawl space, it can be tough to determine the root cause. A licensed waterproofing company will be able to assess your property and identify whatever issues(s) are causing water to enter your crawl space. But the first step is to check your gutters and downspouts.
Make sure your gutters are clear of debris and that your downspouts are draining water at least 15 feet away from your home. Otherwise, that standing water will seep downward into the soil and eventually make its way into your crawl space. Water looks for the path of least resistance. And in this case, that path is right through the footing and foundation walls.
Culprit #2 Humidity In Your Crawl Space
Water is the easier culprit to detect because you can see it with the naked eye. While you can’t actually see humidity, you can definitely see the effects of it. Just because your crawl space is free of any standing water, this doesn’t mean you’re off the hook.
Controlling the humidity in your crawl space is possible, but why is it necessary? An overly humid crawl space can create several different problems, including:
Mold Growth
In order to grow, mold requires food, water and oxygen. You can’t change the fact that your crawl space contains wood (the food) or oxygen. You can, however, control the presence of water and humidity in your crawl space. When left untreated, mold will release thousands of spores into the air. These spores will then travel upward through your living space.
Poor Air Quality
A common misconception is that any mold in your crawl space will stay in your crawl space. Unfortunately, this isn’t the case. Thanks to the stack effect, a phenomenon that draws air up from the lower levels to the upper levels, you are breathing in whatever’s in your crawl space. Inhaling those harmful mold spores can lead to symptoms such as coughing and wheezing. It can even cause you and the other people in your home to develop allergies and respiratory problems.
This is why it’s so important to treat any existing mold and prevent future mold from growing. If you detect musty odors or experience symptoms such as itchy eyes, allergic reactions, coughing, shortness of breath and other physical discomforts, check the crawl space for mold. If mold is present, you’ll want to have a mold remediation company treat the mold to improve your air quality and ensure no one in your home will suffer from the short-term and long-term effects of breathing in mold spores.
Wood rot and structural damage. Wood Rot & Structural Damage
It doesn’t take much for mold to grow on wood. When wood has a moisture content of 16%, this is the threshold for mold growth. As mold feeds on the wood, it begins to rot and deteriorate over time. Remember that your crawl space creates the foundation for your entire home.
Everything rests on the safety and stability of your crawl space. By controlling that indoor humidity, you will prevent fungi from destroying the wood and compromising the structural integrity of your home.
Pest Infestations
Rodents, termites and other pests gravitate to damp environments. Think about how rats are typically known for living and breeding in the sewer systems. The best way to prevent unwanted guests from invading your crawl space—and in turn, your home—is by controlling the humidity and keeping your crawl space dry.
High Energy Bills
When left to its own devices, your crawl space will become Humidity Headquarters every summer. When that humid summer air enters your crawl space, the heat becomes trapped and contained. The heat will then travel upward and enter your home through your floors and ductwork. Your air conditioner will overwork itself to try and account for the excess heat and humidity in your home, resulting in higher energy bills.
By controlling the humidity, you can prevent that heat from building up and placing unnecessary strain on your air conditioner. This will not only keep your energy bills lower, but it will also help prolong the life of your HVAC system.
What’s the Optimal Humidity Level for NJ Crawl Spaces?
50% humidity is the sweet spot for NJ crawl spaces. While we’ve explained in-depth why you don’t want your crawl space to be overly humid, you don’t want it to be too dry, either. When humidity levels are too low, this can create issues such as dry rot, wood shrinkage/cracking, increased static electricity, upper respiratory issues and more.
The reason we talk so much about the problems associated with high humidity rather than low humidity is because New Jersey is typically a very humid state. This is why installing a dehumidifier is the final step of our crawl space waterproofing process. But as you are controlling the humidity in your crawl space, you don’t want to go overboard and bring those levels too low.
This is why around 50% humidity is considered the perfect balance that will keep your crawl space dry, but not too dry.
Still Have Questions?
Give us a call today to speak with one of our basement waterproofing experts.
Subscribe to our newsletter for the latest tips, tools & news!
For more information about basement waterproofing services or to find out if Blue Umbrella serves your area, see our complete service area.
