Skip to Main Content
FFA employees in the office

Is Venting the Crawl Space A Good Idea?

Get A Free Estimate

The crawl space is a popular feature in buildings across the U.S. It’s a cheaper alternative to the basement yet offers more function than a slab foundation. Plumbing, ductwork, and electrical systems are all conveniently located inside it. However, it’s prone to moisture and mold problems.

For many years, building codes required crawl spaces to be vented. People didn’t question the logic behind this requirement. However, things started changing in the mid-1980s when building scientists started investigating homes with moisture issues.

Should You Vent Your Crawl Space?

Crawl space ventilation is one of the most debated questions in the construction industry. Research has shown that venting your crawl space, especially in mixed or hot, humid weather is likely to increase crawl space moisture. Moisture buildup, in turn, instigates other problems within the home.

When warm, moist outside air enters your crawl space through the vents, it condenses or collects, causing your crawl space humidity levels to peak. The outcome is always unpleasant. Mold and mildew will grow, wood will rot, and metal will rust.

These openings also make moisture control difficult as moisture-laden air keeps flowing into the crawl space from the outside. When this air gets inside, it rises into the living space (the stack effect) where it changes the internal conditions. Floors and walls may feel cooler and moisture droplets may form on cooler surfaces.

Looking at the effects outside air has on your crawl space, it best to not leave it vented.

The Impact of Ventilation on Crawl Spaces

Other than high moisture content, there are many more concerns that arise because of crawl space vents. They include:

Rot and mold buildup

During summer, warm, moist outdoor air enters your cooler crawl space and condenses on the surfaces. The steady increase of moisture in your crawl space creates a conducive environment for the growth of mold and mildew. Excess moisture also causes wood rot, which attracts insects like carpenter ants and termites, whose colonies cause additional wood damage.

Water coming in from outside

When there is a deluge, water may find its way into your crawl space through the open vents.

Leaking heating and cooling

Crawl space vents also allow heat and cold to escape from your home. You’ll find yourself continually adjusting the internal conditions. And this will reflect in higher monthly energy bills.

An opening for pests

Vents provide an entryway for pests into your home. When these critters come in, they will tear insulation, chew your wooden beams, and contaminate the floors with their urine and fecal matter.

What’s the best solution?

For these reasons, ventilating your crawl space may not be the best thing to do. Seal your vents with vent covers and encapsulate it with a plastic vapor barrier to isolate it from outdoor temperature and moist air.

Sealing your vents isn’t enough deterrent against moisture. Water and air will still find their way into the crawl space. What you need to do is cover the crawl space floor and walls with a 20-mil vapor barrier.

This barrier goes around beams and wood joists all the way to the grade level. Next, seal openings around your plumbing, electrical wiring, and door frames. This way, you stop unwanted air from flowing from the cooler crawl space area to other sections of your home.

Once you do that, you can go ahead and condition the crawl space. This is where an energy-efficient dehumidifier comes in. Your best option is a unit that will clean and filter the air, control moisture and humidity, and reduce odors and the potential for mold growth. With proper conditioning and sealing, your crawl space will remain dry, mold-free, and less attractive to pests for years.

If you are concerned about the condition of your crawl space, get a safe and comprehensive crawl space inspection from Florida Foundation Authority. With years of experience maintaining and repairing crawl spaces, Florida Foundation Authority is a leading crawl space contractor in Orlando, FL.

We offer a full set of crawl space repair and maintenance services. No matter what you’re experiencing, you can count on us to provide lasting solutions. Do not hesitate to contact us today for a free inspection of your crawl space.

Publish Date:

Last Modified Date:



3723 Hogshead Rd
Apopka, FL 32703