Close the Foundation Vents That Let Humid Air In

Crawl space vent covers seal the open foundation vents on a crawl space so the space can be kept dry and conditioned instead of swapping air with the outside. In a humid climate, open vents let warm summer air in to condense on the wood, let cold winter drafts pull heat from the floor above, and give pests an easy entry. A sealed, insulated cover closes the opening with a gasket so none of that gets through. Epp Foundation Repair installs them as part of converting a vented crawl space to a sealed one.

In Nebraska, Iowa, Kansas, and Missouri, sealing the vents is usually the right call, because open vents tend to add summer moisture rather than remove it. The reliable approach is to seal the vents, lay a vapor barrier, and condition the air with a dehumidifier so the crawl space can stay dry year round. Sealing vents on a crawl space with an exposed dirt floor and no dehumidifier helps less, which is why Epp Foundation Repair installs covers as part of a full system rather than as a standalone fix. The crew will tell you what makes sense after measuring your humidity.

Yes, as part of a sealed system. Open foundation vents are the main way humid outside air enters a crawl space in summer, where it condenses on the cool wood and feeds mold. Sealing the vents stops that exchange, and a dehumidifier then holds the sealed air below roughly 60 percent humidity, the level under which mold and rot do not progress. The vent covers and the dehumidifier work together. The covers close the openings, and the dehumidifier dries the air that remains. One without the other only does part of the job.

Yes. A foundation vent screen is no real barrier, since mice and insects get through torn or loose screens easily, and a mouse only needs a gap the size of a small coin. A solid, gasketed vent cover closes the opening completely, so it removes one of the most common entry points into a crawl space. Sealing the vents is part of how Epp Foundation Repair reduces pest pressure, by taking away the open doors and, with encapsulation, the damp conditions pests come for. For an active infestation you would still need a licensed pest control company first.

Vent covers are usually priced as part of an encapsulation, since they work with the vapor barrier and dehumidifier. The cost depends mainly on how many vents your foundation has to seal. A Customized Repair Estimate after an on-site inspection reflects your scope.

The covers seal the foundation vents permanently as part of converting to a sealed crawl space, so they are not opened for routine access. Inspection and service happen through the crawl space access door, which is built to open and close cleanly, rather than through the vents. Epp Foundation Repair installs a sealed, insulated access door alongside the vent covers for exactly this reason, so you keep easy access to the space while the vents stay closed to humidity and pests.