What Are Flood Vents? Flood Openings and Elevated Homes Explained

Flood vents, also called flood openings, are openings built into the walls of an enclosed area below an elevated home so that floodwater can flow through instead of building up pressure against the walls. They matter most for homes raised on piers, pilings or columns with an enclosed space underneath, such as a garage or storage area. Without proper openings, that enclosure can be treated very differently by an underwriter than one that has them.

This article covers what flood openings are and why they matter, how underwriters look at an enclosure that may or may not have proper openings, what to document when you have an elevated home with an enclosure, and the common mistakes homeowners make with these spaces.

What Flood Openings Are For

An elevated home is raised so that living space sits above expected flood levels. The area underneath, whether it's open or enclosed, is a different story. If that lower area is enclosed with solid walls and floodwater rises outside, the water pushes against those walls from the outside while the inside stays dry, at least until the water finds a way in. That pressure difference can damage or even move a structure that isn't designed to handle it.

Flood openings solve this by letting water flow freely in and out of the enclosure as flood levels rise and fall, so the pressure stays roughly equal on both sides of the wall. The goal is to let water pass through the space rather than pile up against it.

Why Enclosures Below Elevated Homes Need Them

The space below an elevated home is generally meant to be used for parking, storage or building access, not as finished living space. When that space is enclosed, the walls around it need flood openings for the enclosure to be treated as what it's meant to be: a transitional space that floods along with the ground around it, rather than a sealed room that resists the water.

An enclosure that's missing openings, or that has openings that have been blocked, covered or otherwise compromised, doesn't function the way an underwriter expects an enclosure to function. That changes how the space is evaluated.

How Underwriters Look at Enclosures

When an underwriter reviews an elevated home, the enclosure below it gets specific attention. An enclosure with proper flood openings is generally evaluated as what it is: a vented space used for parking, storage or access. An enclosure without proper openings can be treated as if it were living space instead, because without the openings, nothing distinguishes it from a sealed lower floor that happens to have been built close to the ground.

That distinction matters a lot for how the building is rated. A properly vented enclosure lets the underwriter focus on the elevated living area above it. An enclosure without proper openings pulls the evaluation down to that lower level, closer to the ground and closer to expected flood depths.

This is also why what's actually inside and around the enclosure matters, not just the walls themselves. If the enclosure has been finished out, used as living space, or had its openings closed up for comfort or security reasons, that changes the picture an underwriter is working from.

What to Document

If you own an elevated home with an enclosure below it, a little documentation goes a long way when it's time to get a quote:

• Photos of the enclosure walls, showing the openings clearly, from both outside and inside if possible.
• Photos of what's stored or used in the space, to show it's being used as parking, storage or access rather than finished living space.
• Your elevation certificate, if you have one. Section A, Item A8 on the FEMA elevation certificate records the number and total area of flood openings in the enclosure. If you have a certificate, this is the field that speaks directly to your vents.
• Any changes since your last survey or certificate, such as openings that were added, replaced or modified after the certificate was completed.

Sterling does not require an elevation certificate to quote, so a quote can move forward with photos and a general description even without one. If a certificate exists, though, Item A8 gives an underwriter a documented number rather than a description to go on.

Common Mistakes With Flood Vents

• Blocking or sealing vents for comfort, security or pest control. Covering an opening to keep out drafts, bugs or intruders also defeats its purpose during a flood.
• Finishing the enclosure into living space. Drywall, flooring, furniture or a window unit in the enclosure can shift how the whole space is evaluated, regardless of the walls' openings.
• Assuming any opening counts. Not every hole in a wall functions the way a flood opening is meant to. If you're not sure whether your enclosure's openings are doing the job, it's worth having it looked at.
• Not knowing whether the enclosure has openings at all. Some owners have never checked, especially if they didn't build the home. A quick look, or a look back at your elevation certificate, answers the question.
• Letting storage block the openings from the inside. Boxes, equipment or shelving piled against the wall can obstruct an opening even when the wall itself is built correctly.

Pro Tips from Sterling Flood Underwriters

Walk the enclosure before you request a quote. A quick look at the walls tells you more than guessing, and a photo saves a follow-up question later.

Describe the enclosure's use in plain words. A sentence like "ground-level garage with vents, used for parking and storage" gives an underwriter the picture immediately.

Check Item A8 if you have a certificate. It's a small field with a disproportionate effect on how an elevated home's enclosure is evaluated.

Get a Quote

Have an elevated home with a vented enclosure underneath? A few photos and a short description of the space help get your quote request moving. Get a flood insurance quote from Sterling Flood.

Frequently Asked Questions

What's the difference between a flood vent and a regular vent?

A flood opening is specifically built to let floodwater pass through a wall and equalize pressure as water rises and falls. A vent built for ventilation, airflow or pest control may look similar but isn't necessarily doing the same job.

Do I need flood openings if my enclosure is only used for storage?

The use of the space matters, but so do the openings themselves. An enclosure without proper flood openings can be treated differently by an underwriter regardless of what it's used for, so it's worth checking both.

Does Sterling need my elevation certificate to know about my vents?

No. Sterling does not require an elevation certificate to quote. If you have one, Item A8 documents the number and area of openings, but photos and a description can also move a quote forward.

What if I already finished out my enclosure?

Mention it when you request a quote. A finished enclosure, or one with its openings closed up, is evaluated differently than an open, vented space used for parking or storage.