Crawl Space Flood Vents

Are Flood Vents Necessary?

There are two schools of thought surrounding flood vents in the crawl space, each on total opposite sides of the issue.

What is the purpose of Flood Vents?

Traditionally, crawl spaces have been built with flood vents installed to alleviate the danger of collapse during a severe water event. The idea is to allow the water to flow through the crawlspace, rather than keeping that force trapped with nowhere to go, possibly causing significant damage to the supporting structure. In flood zones, homes are dictated by code to be constructed with flood vents within the foundation, a minimum of two per enclosed space is required.

These flood vents are often left open, or with only grates, grilles, screens or makeshift covers that don’t impede the flow of water. This can also leave your crawl space vulnerable to pests and unwanted vegetation that takes root beneath the home, among other things.

There are many types of flood vents, however, this may not be the case with all models. Some can open and close at your choice, or automatically, and some even have measures to keep pests and plants out of the space. Flood vents also come in many different materials such as stainless steel, plastic, and treated wood.

Then there is the theory that places flood vents in the “bad idea” category. Some believe that flood vents can possibly cause mold, mildew, and high energy bills within the home, bringing down the productivity of the system by 25% to 40%. The open nature of the crawl space makes it difficult to insulate, and any air contamination originating below can easily come up into the home. This contamination can increase humidity and mold growth in living spaces.

In the end, the benefits of flood vents heavily depend on where your home is located and if they are required by code. Contact your local expert for more information on the pros and cons of flood vents in your home.