Everything Homeowners Need To Know About Crawl Space Waterproofing

It doesn’t have to be a flood or a major plumbing leak. Even a small amount of moisture in your crawl space can can wreak havoc, not only in the crawl space itself, but in your home as well. Moldy, rotten wood, spongy floors, wood-eating pests, and eventually, structural damage if you don’t get the moisture under control.
Because moisture can damage both your crawl space and your home’s foundation, you’ll want to catch minor moisture issues early, before they have a chance to develop into big problems.

Does My Home Have A Crawl Space?

The most common foundation types are slab, basement, and crawl space. A slab foundation sits directly on the ground. A crawl space foundation typically includes a 1-3 foot ‘’buffer zone’’ between the soil and the home’s ground floor. It’s enough space to crawl around in, but not to stand up. A basement foundation has – you guessed it – a basement. 
A crawl space provides easy access to the building’s plumbing, heating, cooling, and electrical systems. This means maintenance is easier than it is with a slab foundation. In damp climates, crawl spaces also keep the home off the ground.
If you need to walk up at least a couple of steps in order to enter your home, it probably has a crawl space. In other words, it’s not flush with the ground. 
The entrance to the crawl space might be on the exterior of your home, or inside somewhere. You’ll often find entrances to crawl spaces inside closets and pantries. 
Yes, a crawl space can (and should!) be sealed and waterproofed. However, that doesn’t mean it’s a living space. You can use a sealed crawl space for storing non-flammable items though.

How Does Moisture Get Into A Crawl Space?

There are a variety of ways moisture can enter your crawl space including – but not limited to – rain, moisture in soil, flooding, plumbing leaks, through concrete or brick walls, via poor drainage around the outside of your home, and because of problems with gutters and downspouts. Even moisture from the outside air can cause problems inside your crawl space.
Moisture inside your crawl space will, over time, lead to mold growth, wood rot, and other problems. Aerosolized mold in your crawl space will make its way into your home, lower the quality of the air, and could cause respiratory issues for sensitive individuals. Moisture in your crawl space can be prevented via waterproofing.

Why You Should Waterproof Your Crawl Space

You should waterproof your home’s crawl space because crawl spaces are susceptible to problems with moisture, problems that can cause significant damage to both your home and your health.
Crawl space waterproofing will lower your energy bills. Now, this might sound odd. However, unless you live in a region with very low humidity, the air in an unsealed crawl space is going to be damp, and this damp air will make its way up and into your home. Since damp air costs more to both heat and cool, this increases your energy bill. So, if you want to lower your energy bill, seal and waterproof your crawl space so that the air stays dry.
Because crawl spaces are typically moist environments, they’re perfect ‘’petri dishes’’ for mold. Mold will eventually rot the wood and cause rust to form on metal ductwork. Also, as we just mentioned above, airborne mold spores will come up from the crawl space and enter your home.
Of course, let’s not forget the various creatures who thrive in the kind of damp soil found in crawl spaces: termites, mice, rats, spiders, and even snakes.  Yuck.

Benefits Of Waterproofing Your Crawl Space

If humidity is a problem in your region – such as Florida or the Midwest – your unwaterproofed crawl space will be humid, and this moist air doesn’t stay in your crawl space. It makes its way up into your home and, as a result, makes it a less comfortable living space. Humid air makes temperatures feel both hotter and colder, so you end up using more energy to heat and cool your home.
When you waterproof your crawl space you get cool, dry air coming up into your home instead. This means less money spent on heating and cooling.
A sealed, waterproofed crawl space also improves the air quality in your home. Instead of moist air with aerosolized mold in it, you get cool, dry, mold-free air. Since mold can cause allergies and respiratory problems, this is a significant improvement. 
The dry environment inside a waterproofed crawl space means no wood rot. Wood rot is dangerous because it can affect your home’s structural integrity and lead to a repair that is both necessary and expensive. Also, termites and other pests love the cool, damp environment inside an unwaterproofed crawl space.  
A waterproofed crawl space also keeps moisture safely away from electrical wiring. This reduces the risk of both fire and electrocution.

Signs Your Crawl Space May Need Waterproofing

Signs your crawl space might need waterproofing include…
  • Musty odors. 

  • Visible moisture condensation on anything in the crawl space including wood, metal, and soil.

  • Visible mold and mildew.

  • Standing water

  • Signs of insect or rodent infestation. 

  • Efflorescence. This is a white, powdery substance that moisture leaves behind on concrete or brick

  • Rust on pipes or ductwork

  • Rotten wood

  • A warped hardwood floor. This is almost always a sign of moisture in your crawl space

You want to detect moisture problems in your crawl space early, before they have a chance to cause extensive damage to your foundation, damage that will be expensive to fix. A good rule of thumb is to inspect your crawl space once or twice a year. If you don’t want to do this yourself, you can hire someone to do it for you.

Crawl Space Waterproofing Methods

There are two ways to waterproof a crawl space. One focuses on the exterior of the building and the other focuses on the interior.
Exterior crawl space waterproofing methods
Waterproofing your crawl space from the exterior of your home involves installing a moisture barrier around the foundation. It might also include a drainage system as well, in order to reduce the hydrostatic pressure on the foundation’s walls. This is done because groundwater and moisture-saturated soil pushing against the foundation can cause cracks that allow even more moisture to get into your crawl space.
Interior crawl space waterproofing methods
Waterproofing your crawl space from the inside involves installing a vapor barrier on the floor, walls, and sometimes even the ceiling. This is called crawl space encapsulation. It’s very effective and is sometimes used in conjunction with other methods that help dry up moisture such as dehumidifiers.

Crawl Space Encapsulation Pros And Cons

Reasons you might want to have a sealed crawl space include the fact that it reduces moisture thereby reducing mold growth, pests, and the cost of heating and cooling your home. You can also use the encapsulated crawl space for storage of non-flammable items. Kids will love it because it’s bright, clean, and the perfect spot to erect a fort!
The only real con to a sealed crawl space is that it’s not free. However, the benefits of crawl space encapsulation are well worth the cost.

How Much Does Crawl Space Waterproofing Cost?

The cost of creating a sealed crawl space will depend on your geographical location and what exactly needs to be done. Obviously, if you utilize both the exterior and the interior waterproofing methods, it will cost you more than if you choose only one of the two options.
Unfortunately, unless the moisture problem was caused by a natural disaster, your homeowners insurance probably won’t cover the cost of crawl space encapsulation. However, it doesn’t hurt to check to make sure.

Selling A Home With A Crawl Space Moisture Problem

Yes, it’s possible to sell a home with a crawl space moisture problem. All you need to do is disclose the problem to the buyer (you’re required by law to do this) and adjust the price. Many investors are interested in less-than-perfect homes.

How Can I Prevent Water In My Crawl Space?

There are a variety of ways you can prevent water from getting in to your crawl space including…
  • Installing French drains to ensure that water drains away from your foundation and crawl space.

  • Installing a rain garden

  • Planting water-absorbing vegetation around your home

  • Asking a professional to regrade the slope of your yard so that water drains away from your home, and doesn’t pool around the foundation

Moisture is something you definitely don’t want in your crawl space. Even small amounts of it can cause mold to grow, rot wood, negatively impact the air quality in your home, increase your energy bills, and provide a perfect breeding ground for various types of creepy crawlies. If left unchecked, it can even lead to serious structural damage. Therefore, a waterproofed and sealed crawl space is a home improvement that’s well worth the cost.