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crawl space vent problems

To Open or Close Crawl Space Vents in Summer – Which Way to Go?

Everyone wants to have a clean, dry, healthy, and mold-free crawl space. But does everyone attain it? Absolutely not. As long as the vents remain open, you will never have a dry space. You will fight a losing battle with moisture until you finally seal the vents and encapsulate the crawl space. Why wait for things to take a drastic turn before you act? 

Some homeowners still use vents as local codes have dictated for a long time. They believe these fixtures aid air circulation, which ultimately cools their living spaces. Numerous studies have quickly disapproved of the use of crawl space vents, so they are no longer tenable as ventilation mechanisms. 

Are Crawl Space Vents Useful? 

Crawl space vents aren’t effective, and the reason is their logic is faulty. If anything, they defeat the purpose for which they are created. A crawl space measuring 1,500 square feet can produce up to 15 gallons of moisture in a day. Where do you think most of this moisture will go? Right into your home. 

Your home will become much healthier and drier without them. Instead of venting, seal these fixtures and encapsulate and condition the crawl space. 

Crawl space vents can foster many problems. Your number one worry is water droplets that arise due to condensation. This happens when moist warm air sweeps across cold surfaces and walls. Condensation can trigger mold growth, cause wood rot and rust, and staining of walls. 

Over time, the continuous flow of air through crawl space vents can weaken the underlying wooden structures. You will find that rotting beams or decaying joists won’t support the load above. This will force you to carry out extensive and often costly repairs. 

Your HVAC won’t have it easy. In fact, you will be forced to run it for several hours as you try to bring down moisture levels and create a comfortable indoors. And the more you use it, the higher your energy bill rises. 

Outside air doesn’t just bring in moisture but pollutants, radon gas, and pollen. All these are things that will affect the health of your family members. Kids may cough a lot and anyone with asthma will see their condition grow from bad to worse. 

Let’s say the temperature outside is 85 degrees. You turn on the air conditioner to bring it down and feel more comfortable indoors. Someone opens the windows, and warm air rushes in. Temperatures go up again, and condensation occurs. 

Benefits of Sealing the Crawl Space 

Wondering what you’ll gain by sealing and conditioning the crawl space? Here’s how: 

  • Dry and durable: Air sealing, insulation, and moisture control all create a dry under-floor area. 
  • Increases home value: Sealing vents and encapsulating the crawl space makes your home more appealing to home buyers. Floors will become warm and comfortable. 
  • Simplifies inspections: Sealing makes inspection and repairs easier as the crawl space remains clean. 
  • Enhances your home’s energy efficiency: Temperatures in closed crawl spaces are more stable compared to those with vents. 

Protecting Your Crawl Space from Moisture 

Enclose your crawl space with a 20-mil plastic vapor barrier. This barrier goes over the floor and walls. Leave a three-inch gap for a visual termite inspection. Encapsulation locks out warm, moist air, wood damaging insects, and pests. 

Next, air seal the crawl space to stop air leakage. Pay attention to areas between the rim board and subfloor, rim board and sill plate, and sill plate the foundation wall interface. Don’t forget the area between concrete or masonry walls and the cripple studs edge. And the most important part is the vents themselves. Have airtight and secure vent covers placed on the home’s exterior to properly seal the crawl space from outside air, water, and pests. 

Insulate the crawl space walls and rim areas using rigid panels like ExTremeBloc ™ to minimize air leakage and reduce condensation levels. 

It’s also important to take necessary steps to condition the air and keep moisture and humidity levels low. 

That’s where an energy-efficient dehumidifier comes in. This unit will clean and filter the air as well as reduce odors and the potential for mold growth while keeping humidity in check. 

Take the Next Steps 

Columbia, SC, homes with sealed vents and closed crawl spaces outdo their counterparts with crawl space vents. The two will be worlds apart with regards to air quality, mold resistance, structural health, and energy efficiency. Encapsulated homes will also remain drier during hot and humid summer months when humidity levels can easily cross the 60% mark. If you’re unsure of what to do, talk to Mount Valley Foundation Services, your local crawl space contractor. We will provide you with a free crawl space encapsulation inspection and quote along with recommendations to protect this valuable space.