What Are Crawl Space Vent Covers?
Crawl space vent covers are insulated seals that close the foundation vents so humid outdoor air can no longer enter the crawl space. The open vents built into older homes were intended to ventilate the space, but in Alabama's humid climate they do the opposite, admitting warm, moist air that condenses on cool surfaces and keeps the crawl space wet. Sealing those vents is a core step in converting a damp, vented crawl space into a dry, sealed one. APS installs durable, sealed vent covers as part of encapsulation, closing each vent so the space can be dried and its humidity controlled from within.
How Crawl Space Vent Covers Work
Each foundation vent is fitted with an insulated cover that seals tightly against the opening, blocking the exchange of humid outdoor air. With the vents closed and the space lined with a vapor barrier, the crawl space is no longer taking on moisture from outside, so a dehumidifier can hold it at a healthy humidity. Sealing the vents is what allows the whole sealed-crawl-space approach to work, because an encapsulated space with open vents would keep pulling in the very air that causes the problem.
“Every open vent is a straw pulling humid Alabama air into the crawl space. We cap them so the space can finally stay dry.”
How APS Installs Crawl Space Vent Covers
- 1
Inventory the Vents
APS locates and measures every foundation vent so each gets a properly sized, sealing cover.
- 2
Prepare the Openings
Each vent opening is cleaned and prepared so the cover seats and seals against the foundation.
- 3
Install Sealed Covers
Insulated vent covers are installed and sealed tightly to close off the outdoor air path.
- 4
Integrate With Encapsulation
The sealed vents are coordinated with the vapor barrier and humidity control so the space is a continuous sealed envelope.
- 5
Verify the Seal
APS confirms each vent is fully sealed and that the space is ready to be dried and conditioned.
What Crawl Space Vent Covers Cost and What Is Covered
Cost Range
Cost depends on the crawl space size, access, and system specified. APS provides a free written estimate after the assessment.
Warranty
APS in-house workmanship warranty plus manufacturer warranties on system components, both fully transferable to future owners
Frequently Asked Questions
Will sealing the vents trap moisture in the crawl space?
No, as long as the space is dried and its humidity controlled after sealing. The moisture in a vented crawl space comes from the outdoor air and the bare ground. Sealing the vents and adding a vapor barrier and dehumidifier removes both sources.
Do I need to seal every vent?
Yes. Leaving even a few vents open lets humid air continue to enter and undermines the sealed approach. APS covers and seals all of them for the strategy to work.
Is this different from crawl space doors?
Same idea, different opening. Vent covers seal the foundation vents; the crawl space door seals the access entry. Both are openings that have to be closed to keep the sealed space dry.
Can I just buy foam vent plugs?
Loose foam plugs rarely seal well or last in Alabama's conditions. APS uses durable, insulated covers that seal properly and hold up, integrated with the rest of the encapsulation.