The most common question property owners ask after a flood event is some version of: “How did the water get in?” And the most common answer is: the doors, because buildings aren’t often designed with flood proof doors.
Standard commercial and residential doors – even well-maintained, well-sealed ones – are not designed to hold back floodwater. They’re designed to keep out drafts, insects, and intruders. Water under pressure is an entirely different problem, and most door systems simply aren’t built for it.
Flood proof doors are one of the highest-impact things you can do to protect a property from flood damage. Here’s how it works.
Why Standard Doors Fail in a Flood
A typical commercial door has multiple potential failure points:
- The threshold gap – the small gap between the bottom of the door and the floor is intentional under normal conditions, but becomes a flood entry point as water rises
- The door frame seal – standard weatherstripping compresses against the frame to block drafts, but it can’t withstand hydrostatic pressure from standing water
- The door panel itself – hollow-core or standard solid-core doors can flex, bow, or fail when water pressure builds against them
- Hardware penetrations – hinges, locks, and door closers create small penetrations in the frame that water will find
Even 3–4 inches of standing water outside a standard commercial door will begin entering through the threshold gap. By the time water is knee-high outside, a standard door is likely to fail catastrophically.
Flood Proof Doors Solution: From Temporary to Permanent
Option 1: Flood Door Panels (Deployable)
The most common temporary solution for commercial properties is a deployable door protection panel – a modular barrier installed over the existing door frame as a flood event approaches. These panels attach to anchor channels embedded in the door frame and create a watertight seal rated for specific water depths.
This approach works well when:
- You have advance warning before a flood event
- You have trained staff on-site to deploy the panels
- The door opening has been prepped with the appropriate anchor system
Option 2: Permanent Flood Doors
Permanent flood doors replace your existing door with a system that functions as a standard door under normal conditions – opens, closes, locks normally – but is engineered to provide a watertight seal when a flood threatens. No panels to install. No staff deployment required. Just close and lock the door.
This is the right choice for:
- High-risk properties that flood frequently or with little warning
- Entry points that are difficult to monitor or deploy protection for quickly
- Mission-critical facilities where any deployment delay is unacceptable
Option 3: Passive Automatic Flood Door/Gate
For openings that need to be protected without any human involvement at all, passive automatic floodgates deploy automatically as water rises. These are ideal for secondary entrances, utility access points, and any opening where manual deployment isn’t reliable.
What “Flood Proof Doors” Actually Means
A door or door protection system is only flood proof to a specified depth. When evaluating flood door solutions, look for:
- Water depth rating – the maximum standing water height the system is certified to withstand
- Hydrostatic pressure testing – verification that the seal holds under actual water pressure, not just during bench testing
- Third-party certification – look for FM Approval and compliance with FEMA/NFIP standards
- Frame compatibility – the protection system must be properly anchored to the existing frame or a purpose-built frame
FRA’s door protection systems exceed FEMA and NFIP guidelines, meet U.S. Army Corps of Engineers standards, and carry FM Approval.
Don’t Forget: Other Openings Beside the Door
Fully flood proof doors don’t help if water gets in through the window next to it. When you’re flood proofing your doors, it’s the right time to evaluate:
- Window and glass protection for adjacent storefront or lobby glass (Window & Glass Protection)
- Floor drain protection to prevent backflow flood entry (Floor Drain Protection)
- Electric panel covers to protect electrical panels near flood-vulnerable areas (Electric Box Cover)
- Flood covers to protect immovable equipment (Flood Cover)
Looking to Flood Proof Doors on Your Property?
Whether you need a deployable door panel system, a permanent flood door, or a full assessment of all vulnerable openings in your building, FRA has the solution. Contact us to get started.
