3 Common Causes of Crawlspace Moisture


Crawlspaces may not be as useful as basements, but they do play an important role in the overall efficiency of your home. A crawlspace puts an extra air cushion between the home and the ground, helping keep the ground moisture at bay, as well as preventing air leaks. But a crawlspace itself is not without issues. Allow our Maryland crawlspace waterproofing experts to give you an overview of the potential crawlspace issues and what causes them.

What’s the Deal With the Crawlspace?

In Maryland and surrounding states crawlspaces are not very common. So if you’ve purchased a Maryland home with a crawlspace, you may be scratching your head as to why it’s there and what sort of issues it may cause. Crawlspaces are frequently built instead of basements due to financial reasons or poor soil conditions. Building a full basement requires extensive digging, which in northern states we have to do anyway because the foundation has to be set below the frost line. In warmer climates, however, basements are an optional added expense, so many homeowners choose a crawlspace instead.

As the word suggests, a crawlspace is a space between the bottom of your house and the ground. It’s designed to lift the home off the ground, so that moisture doesn’t transfer as easily and your home has the room to “breathe.” A crawlspace also provides a convenient maintenance access to utilities, such as plumbing and electrical.

Problems With Crawlspaces

Well, a major problem with a crawlspace is that it’s not a basement. At best you can use it for storage of rarely used items, but even then you might run into moisture issues. Moisture is probably the main issue you have to worry about when it comes to crawlspaces. And here are some of the main causes of moisture that you can eliminate with the help of your local Maryland waterproofing company.

Standing Water

Although a crawlspace doesn’t go as deep below grade as the basement, it is still prone to standing water issues. Water could be coming from a plumbing leak or, most likely, from an improperly sloped yard. If your yard naturally slopes toward your home instead of away from it, the gravity will direct surface water to your crawlspace. And because most crawlspaces don’t have a concrete floor, it’s easy for the water to enter the space and create puddles. Thankfully, standing water is easy to detect, and a knowledgeable waterproofing contractor should be able to identify its source and correct the problem.

Moisture from the Soil

As we mentioned, most crawlspaces don’t have a floor. In the best case scenario they are covered with gravel, but most of the time it’s just plain, old dirt. This dirt, along with the porous foundation walls, evaporates moisture into the air, making your crawlspace really humid. And humidity is bad because it contributes to mold growth, wood rot, and can even saturate the insulation and cause it to fall down. Moisture transfer from the soil is inevitable, especially if you live in an area where it rains a lot. However, installing a vapor barrier to cover up all exposed soil will help keep the humidity down.

Air from the Vents

In theory, vents in a crawlspace sound like a good idea: you keep the air moving to help the moisture evaporate and leave the crawlspace. However, in reality vents often do the exact opposite. Whenever the outdoor air is warmer and more humid than the crawlspace, it will bring that humidity and moisture in. Warm air condenses and releases moisture when it touches cool surfaces—that’s why your glass of iced teas “sweats” in summer. The same happens in your crawlspace when it’s 90F outside and just 75F in the crawlspace.

So an unvented crawlspace may be a better option for homeowners in Maryland, where indoor and outdoor temperatures vary significantly throughout the year. Plus, an unvented crawlspace should also help you keep your HVAC running more efficiently without the unnecessary hot/cool air loss through the floor. Just keep in mind that if you choose to go the unvented route, you will need to insulate your crawlspace very well, as well as condition it by supplying a small portion of indoor air.

Contact us today if you have any other questions about crawlspace moisture and how to get rid of it!