Should You Close Crawl Space Vents or Leave Them Open?

Disadvantages of Crawl Space Vents

Venting the crawl space is a bad idea through and through. And even the few pros can’t compare to the many downsides of venting. During rainy weather and humid summer months, you will feel the adverse effects of crawl space vents more than any other time of the year.

When condensation is high, the crawl space environment will become damp. And this goes for all the material inside, including wood and fiberglass insulation, which will soak up moisture. If dampness continues for over 48 hours, mold will start forming on wood and other organic materials inside the crawl space. It will float into your home and trigger respiratory problems, and that means more visits to the doctor.

Venting the crawl space is also disadvantageous as it hastens the destruction of fiberglass insulation. When the material starts soaking moisture like a sponge, it will get heavy and start sagging. Eventually, it will fall off the crawl space ceiling and walls.

The other reason why you should reconsider venting is it encourages wood rot. Moisture will attack and weaken the supporting beams and joists in the crawl space, lowering the structural integrity of your home. It’s another way to say the underlying structures will no longer support the house above.

And then there’s the issue of crawling insects and gnawing pests. Termites and rats come to mind. Both need a space that’s a quarter of an inch wide to enter the crawl space of your Indianapolis, IN, home. When they come in, they will chew your wooden beams and leave pungent droppings that will turn the atmosphere acrid.

Besides letting in pests, venting also increases heating costs by up to 20%. Cold air from the outside creates a stack effect. To harmonize the temperatures inside the home and the crawl space, you’ll have to leave your HVAC running for hours, which could result in higher energy bills.

Lastly, a lot of indoor air originates from the crawl space. Even if you’re able to avoid mold spores, you can’t prevent the dust and allergens that outside air brings into your living space above. These will make breathing difficult.

Is Venting Really Worth It?

It’s clear that venting is a terrible idea. Venting will turn your crawl space into a damp, wet area, teeming with pests and crawling insects, so you’re better off sealing it than leaving it with vents.

Have recurring moisture problems and don’t know what to do with it? Your only hope is to encapsulate the crawl space. During sealing, your local contractor will apply a heavy-duty plastic vapor barrier over the walls and across the floor, going around beams and other obstacles, then double tape the material. What this does is isolate the below-the-ground space from the outside air. Besides, it also keeps out pests and insects.

Don’t let a vented crawl space trouble you or make your home unlivable. We can help you seal it up properly, so it remains clean, dry, and pest-free all year round. Schedule a free crawl space repair quote, and get solid recommendations plus answers to all your questions today!

Holly Richards-Purpura

Content Writer

Holly is a Content Writer for Groundworks who has written and edited web content for the foundation services industry for almost 10 years. With a background in journalism, her passion for the written word runs deep. Holly lives in Columbus, OH, with her husband. Along with educating homeowners, she also has a big heart for the Big Apple.