Once upon a time, vented crawlspaces were commonplace. After all, homeowners believed that venting their crawlspaces would allow them to “air out”, thereby releasing any accumulation of heat. However, this isn’t truly the case, and a vented crawlspace may do more harm than good when it comes to staying comfortable – and safe.
The Problem with a Vented Crawlspace in the South
If you step outside on a nice, sunny Florida day, there’s one thing you’re likely to notice before anything else: the humidity. The air outside is almost always quite sticky thanks to the bodies of water surrounding the peninsula. Basic physics tells us that warm, moist air moves to cooler, dryer air to distribute the energy (in the form of heat) evenly. That’s why you’re advised to leave your refrigerator door closed in the event of a power outage; things can stay cool for quite some time, but opening the door even once introduces heat that may spoil your food. Venting your crawlspace in the south – especially in humid Florida – produces the same effect.
What’s Going on Under Your House?
A vented crawlspace may allow air to circulate, but in this case, that’s a bad idea. Your crawlspace acts like a barrier between your home and the moist ground, but because your home is still relatively close to the ground, problems can arise very quickly if your crawlspace is exposed to hot, humid air. Humid air condenses when it touches a cooler surface, and in this case, the cooler surface is the insulation that lines the underside of your floor. As such, the moist air will enter your insulation, travel to the coolest spot it can find (as close to the conditioned air as it can get), and wreak havoc. Mildew, rot, and even dangerous black mold can result from venting your crawlspace.
How to Seal a Crawlspace
If you have a vented crawlspace and you’re concerned about moisture damage, it’s best to hire a professional contractor to check things out. These individuals have the knowledge and training required to spot potential problems and possibly even resolve them before they get out of control. Sealing a crawlspace (also known as crawlspace encapsulation) typically requires removing the vented areas and adding new masonry in their place, but in some cases, things can be a little more complicated.
Depending on the age of your home and the amount of settling that has occurred, it may be necessary to add additional insulation, seal gaps between your home and the crawlspace, and repair any gaps between the floor and the floor joists, or between your home and the foundation itself. These can and often do occur in Florida homes. Once these things have been remedied, it’s also possible to add a vapor barrier to the walls of the crawlspace, which keeps moisture from penetrating the masonry.
A vented crawlspace used to be the industry standard, but in some climates, like the one here in Florida, it often does more harm than good. It’s important to keep your home safe from the warm, moist air, and professional crawlspace encapsulation is a good way to do it. In fact, it may even help to insulate your home and lower your cooling costs.