Crawl Space Ventilation

Old crawl space thinking and old building codes had builders placing crawl space vents on opposite sides of the house hoping that outside air would enter a vent on one side of the crawl space and exit out the vent on the other side. In effect, this would remove damp, musty crawl space air with clean outside air.

Problem is... that's not how it works.
What the actual science of it tells us is that air movement is upwards in a house, like a chimney. This upward air movement is called a Stack Effect, and this Stack Effect draws air inward from every crawl space vent and up into the living space of the home, eventually exhaling this air out of the upper levels. So where crawl space vents were supposed to remove moisture, they actually contribute to increased moisture in the crawl space during the humid months of summer. These crawl space vents also increase heating costs in the winter from sucking in cold outside air. It's a lose/lose situation.

If Crawl Space Ventilation Doesn't Work, What's the Solution?

There is an informative article by Advanced Energy, a national resource who focuses on applied building science, on venting crawl spaces entitled, "To Vent or Not to Vent." [Download PDF]

Crawl space encapsulation is the solution! Seal the crawl space with a vapor barrier, sealer the crawl space vents with vent covers, seal any gaps or holes to the outside, seal the crawl space door - seal it up as tight as possible.

Crawl Space Encapsulation the Right Way
Install a vapor barrier and then seal any crawl space ventilation. The CleanSpace crawl space encapsulation system is a great solution! CleanSpace is a tough liner that you or any service people can crawl on with no fear of it coming off the walls (yes, you need to cover the walls) or tearing. The vapor barrier also has an anti-microbial agent manufactured into it to kill mold and bacteria that it comes in contact with. The crawl space vent covers and crawl space door are tough and look great - they are also all plastic, as is the entire CleanSpace system, so they never need paint, won't rot, and mold won't grow on them.

Warning: Combustible Appliances (a furnace) Need Air
Certified CleanSpace Installers know all about this... a combustible appliance such as your furnace needs air to operate. So the size of your crawl space makes a difference, as does the possibility of having to draw air from somewhere to feed the appliance. Let a CleanSpace expert help you with this decision.

Conditioning the Crawl Space Air - Good Crawl Space Ventilation
Encapsulating a crawl space is a great start, and in many cases, depending on where you live and relative humidity levels, it may be all you need. But if you need more, a certified CleanSpace Installer can help! There are two good options for conditioning a crawl space. One is to dehumidify the space with an energy-efficient and cost-effective dehumidifier that is powerful enough to do the job - the SaniDry CSB crawl space air system is a perfect option. Two is to draw conditioned upstairs down into the crawl space, which can be done with a crawl space fan system like the Crawl-O-Sphere crawl space conditioning unit.

Do It Once and Do It Right!
Call for a free estimate and inspection from a certified CleanSpace Installer, you will be educated as to the science of a crawl space, and solutions to make your crawl space and entire home healthier. Or contact us online.