Creepy Crawl Spaces
Unless your home is built on a concrete slab or elevated piers, you have a crawl space. It's the space between the ground and the floor under your house. It provides extra room for electrical wiring, plumbing pipes, and HVAC equipment. Since the height is limited, getting into the area must be done by crawling (hence the name).
Crawl spaces are out of sight and therefore easy to neglect. Aside from cupping hardwoods or soft spots in the floor, signs of excessive moisture are hard to detect from inside the home. In addition to being the single most expensive area of your home to repair, maintaining your crawl space is critical to the health and longevity of your home. Moisture, mildew, mold, pests, and wood rot can damage your home’s foundation and introduce toxins to the air you breathe. More than half of the air in your home comes from your crawl space. Mold and mildew can thrive when it's wet.
Crawl spaces with exposed dirt most commonly have trouble with an excess of moisture. Trying to keep water out of the crawlspace is a losing battle, so you need to collect it as it comes in and remove it before it becomes in-home humidity.
Vapor Barriers
A well-laid vapor barrier is the first step to keeping your home protected. It's essentially a large plastic sheet placed over the base of a crawl space to fully cover any exposed dirt. While this doesn’t completely eliminate moisture, it slows the process significantly.
When it comes to thickness, the polyethylene used varies between 6 mil and 20 mil. Vapor barriers should be at least 10 mil in thickness to effectively cover the area and create a moisture barrier. A thicker, more durable 12 or 16 mil barrier is preferable if your budget allows. It should feel thicker than 10 pieces of paper but not as thick as a credit card. Better vapor barrier products incorporate a woven pattern into the sheeting to make it more durable, so also pay attention to the construction.
More important than the thickness is making sure your vapor barrier is properly installed to cover the entire area under your home. If it doesn't extend all the way to foundation walls/piers or has gaps in the coverage, moisture simply moves around the barrier and impacts the uncovered area. Installation could be a DIY project if you have help and don't mind getting dirty, but it's labor-intensive and requires some expertise to be done properly and secured for longevity.
Encapsulation
If a vapor barrier alone isn’t enough to tame moisture problems, encapsulation is the next step, and it's not a DIY endeavor. The plastic sheeting is coupled with sealing tape to cover more area. A complete encapsulation includes drain tile, a sump pit and pump, concrete, insulation, and a dehumidifier to properly condition the air. The installation process takes expertise, and installing a dehumidifier is best left to a trained technician. Our team loves Travis Pfeuffer at Lowcountry Crawl Space. He knows what he's doing and won't rip you off.
Insulation
While it can be tempting to insulate between the floor joists in your crawl space for energy savings, we do not recommend it. The crawl space stays cool year round and it doesn't get cold enough here to need the insulating factor. Rodents love to make nests in insulation, which means the insulation quickly becomes unsanitary. It soaks up moisture and holds on to fungi. Skip the insulation and go for encapsulation instead.
Inspections
A crawl space inspection is included in a home inspection when buying a house but should also be done annually during ownership. Sellers should always assess the state of the crawl space to mitigate any of these potential problems prior to a sale:
Electrical wiring issues
Plumbing issues
Moisture (standing water, damp insulation or warped wooden members)
Pests (bugs, termites, rats, mice)
Mold and mildew
Ventilation issues
Cracks in the foundation
If crawling under your home doesn’t sound fun, partner with a pro. If you have a termite bond, the company is sending a technician under the home once a year to look for signs of wood rot. Reviewing their findings in person can shed light on hidden issues. My annual termite inspection revealed elevated moisture readings under my laundry room. Turns out I had a leak at the washer's drain line and water was hiding under the floor tiles rotting the subfloor!
Whatever you do, just make sure the area is properly maintained so you don't get hit with any surprises when it's time to sell.
