The stack effect is a condition in a home describing the behavior of air based on its density. Air that is warmer has a less significant density than cooler air. As a result, warmer air tends to rise to the top of a home. However, if the air in your crawl space takes on an excessive amount of moisture, the density of the air can increase significantly. In most cases, you’d assume that’d mean air would remain in the bottom of your home. However, if the moisture from your crawl space starts to leak into the rest of your home, that dense air can spread, exposing all belongings and other structural supports to conditions that might result in damage.
There is no getting away from the stack effect, unfortunately. No matter what steps you take, the warmer air in your home will always rise to the top of your home. However, if you work to eliminate the excess moisture in your crawl space, you can prevent wood rot and other moisture-induced damage from appearing in the rest of your home. It is in your best interest to see what you can do to seal off the entirety of your crawl space. Even if you haven’t taken any preventative measures yet, you can keep the vents in your crawl space closed and blocked off while also making sure your crawl space door fits well in its frame.