Crawl Space Repair in MT, including Helena, Bozeman & Missoula.

Crawl Space Ventilation in Montana

How Crawl Space Vents Affect Crawl Space Humidity... And Why

 

When crawl space insulation is saturated with water from condensation, it gets heavy and
drops to the crawl space floor.

Crawl Space ventilation is the answer that contractors have historically given to the issue of crawl space humidity in homes.

Generally, this involves installing vented openings in a cross-sectional area equal to 1/150 of the floor area served.

These crawl space vents are usually fitted with a covering -- usually a wooden/metal grating, or a mesh wire product.

The covering is installed to prevent infestations from rodents and animals, but they cannot prevent insects such as termites and carpenter ants.

 

The Theory Behind Vented Crawl Spaces

crawl space ventilation and air movement in a building

Crawl space ventilation moves moist outside air through the house. This affects utility bills and once mold grows, your health.

Crawl space ventilation was meant to keep a constant supply of fresh air circulating throughout the crawl space environment.

It was thought that this would help to purge the space of the heavy, damp air in the house that settles in the lower levels.

Additionally, some contractors claim that damp, humid air is heavier than dry air, causing all the moisture in the home to sink down into the crawl space.

This belief had become so widespread that crawl space vents were actually written into the International Building Code! In recent years, however, these codes are quickly changing.

 

What Crawl Space Humidity Research Says

Consider these crawl space humidity facts:

  • Isaac Newton discovered in 1717 that wet air is actually lighter than dry air! It makes a lot of sense - if damp air was heavier, what would clouds be made of? And why would crawl space vents, which are at ground level, ever bring dry air into your home?
  • If it's rainy, humid, foggy, or snowing outside, you're bringing wet air into your home.
  • Advanced Energy reports that crawl space ventilation brings wet air into your home [PDF] when it's wet outside. Water that is pooling around your vents, will also flow into the space.
  • Crawl space moisture helps mold, rot, and mildew grow. This means serious damage for your crawl space!

Here's a little more science: Hot air rises, leaving your house through the roof and upper levels. This creates a vacuum below that is filled by air from your crawl space, basement, and from outside. Air in your crawl space eventually enters the rest of your home!

 

Consider These Two Scenarios:

Winter Air - Frigid air fills your crawlspace, making the floor above cold. It cools your hot water pipes, your water heater, your furnace, and your heating ducts. Your utilities work harder and cost you more to run, and your home is drafty and uncomfortable.

Summer Air - Hot, humid air enters the crawl space, where the earth cools it naturally. According to Builder Magazine [PDF], this humidity will lead to condensation on your pipes, wood, and cool surfaces, leading to mold and rot. Damp air rises upward into your home. Wet air is harder to cool than dry air, and you spend more on utilities. Meanwhile, your crawl space insulation gets wet, loses its insulative value, grows mold, and drips to the floor. Moist, rotting wood is a perfect place for termites, ants, rodents, and other creatures to move in!

 

Crawl Space Encapsulation

Crawl space ventilation does not work. If your crawl space is rotting and moldy, then you already know this.

To protect your crawl space, follow these steps:

    1. Eliminate any flooding with a crawl space sump pump system
    2. Seal your crawl space vents and doors with airtight covers.
    3. Line your crawl space walls and floors (even if they are concrete) with a thick, durable plastic liner
    4. Install a self-draining, strong dehumidifier in the crawl space.

 

This keeps everything you don't want in your crawl space outside- including moisture, cold air, termites, and ants. Your crawl space will be dry and usable as storage space, and as an added benefit, a crawl space liner will even serve as a passive radon mitigation system!

Dayspring Restoration would like to help you create a dry, healthier crawl space. If you'd like a free on-site consultation, call or e-mail us today!

Dayspring Restoration services  Montana, including Missoula and areas nearby, including Corvallis, Hamilton, Kalispell, and Stevensville.

Looking for a price? Get a no cost, no obligation free estimate.

Serving Greater Missoula
Our Montana Service Area
Cities in Beaverhead County, MT
Dell
Dillon
Jackson
Lima
Wisdom
Wise River

Cities in Cascade County, MT
Belt
Black Eagle
Cascade
Fort Shaw
Great Falls
Malmstrom A F B
Monarch
Neihart
Sand Coulee
Simms
Stockett
Sun River
Ulm
Vaughn

Cities in Chouteau County, MT
Big Sandy
Carter
Floweree
Fort Benton
Geraldine
Highwood
Loma

Cities in Deer Lodge County, MT
Anaconda
Warm Springs

Cities in Fergus County, MT
Coffee Creek

Cities in Flathead County, MT
Kalispell

Cities in Granite County, MT
Drummond
Hall
Philipsburg

Cities in Hill County, MT
Havre

Cities in Lake County, MT
Pablo
Ravalli

Cities in Lewis And Clark County, MT
Augusta
Canyon Creek
East Helena
Fort Harrison
Helena
Lincoln
Marysville
Wolf Creek

Cities in Mineral County, MT
Alberton

Cities in Missoula County, MT
Bonner
Clinton
Frenchtown
Lolo
Milltown
Missoula
Seeley Lake

Cities in Powell County, MT
Avon
Deer Lodge
Elliston
Garrison
Gold Creek
Helmville
Ovando

Cities in Ravalli County, MT
Conner
Corvallis
Darby
Florence
Grantsdale
Hamilton
Pinesdale
Stevensville
Sula
Victor

Cities in Silver Bow County, MT
Butte
Divide
Melrose
Ramsay

Please call us at: 1-406-662-4002
Testimonials
Before & After
Dayspring Videos:
On Channel 13 News Video We're on Channel 13 News
Watch Video
Montana Disaster Kleenup International