Vented Vs Encapsulated Crawl Space

There are two types of residential crawl spaces: vented or closed. A vented crawl space has louvers that allow external air to enter the crawl space below your home. A closed crawl space has no louvers or uses vent covers to try to prevent external air from entering. Which type of crawl space is right for your home: vented vs encapsulated?

History of Crawl Space Vents

Crawl spaces first gained popularity in the United States in the 1940’s and 1950’s. During that time, building codes recommended ventilating crawl spaces and installing vapor barriers. This included installing numerous vented openings to allow circulation through the crawl space. The theory was that crawl space ventilation ensures a constant supply of fresh air circulating through the crawl space. However, a study by the American Society of Heating, Refrigerating and Air-Conditioning Engineers, INC., found that vents bring unwanted moisture into your home, leading to unwanted consequences.

There are many disadvantages to a vented crawl space that can lead to overall health issues for the crawl space and home. High humidity levels, poor indoor air quality, and crawl space moisture damage are amplified with a vented crawl space.

The higher the outside temperature is, the more moisture there is in the air. As the temperature climbs during the summer months, warm air will try to balance the cooler temperature of your crawl space. Because of this, warm air is driven into the crawl space and moves freely through the vents, causing more condensation on your pipes, wood, and cool surfaces.

Did you know that approximately 50% of air on the first floor of your home comes from your crawl space? That means you breathe in crawl space air. If there were high moisture levels, mold can cause respiratory problems in your living space.

On the other hand, cold air will fill the crawl space during the winer, making the floor above cold. This cools your hot water pipes, water heater, furnace, and heating ducts, causing your utilities to waste energy trying to keep you warm.

Introducing Crawl Space Encapsulation

Today, crawl space codes have changed. A closed or encapsulated crawl space is now preferred to an open, or vented crawl space. Encapsulation protects a crawl space from the effects of moisture by eliminating its sources and actively controlling humidity levels through the installation of a dehumidifier. Even though it is more costly than a ventilated crawl space, the prevention of moisture damage can greatly reduce costly repairs over time.

The Crawl Space Encapsulation Process

1. Clean and sanitize the crawl space to remove debris, mold, mildew, and other contaminants.
2. Seal off entry points and implement measures to prevent rodents from accessing the crawl space.
3. Identify and seal gaps, cracks, and openings in the crawl space to prevent air leakage and moisture infiltration.
4. Install stem wall foam board insulation to provide thermal protection and prevent heat loss.
5. Install a durable 20 mil thick vapor barrier to cover the ground and walls of the crawl space, creating a moisture barrier.
6. Install a dehumidifier to regulate humidity levels and maintain optimal moisture control within the encapsulated crawl space.
7. Install a vinyl tube to route condensation safely from the dehumidifier to a designated drain point.