Keeping Storage Units Dry: What Facility Owners and Renters Can Do to Prevent Flood Damage
- Matthias Herzog
- 4 days ago
- 10 min read
Water damage doesn't discriminate between a climate-controlled interior unit and an exterior drive-up space. Whether you're a facility owner managing dozens of units or a renter storing grandmother's antique furniture, one thing remains painfully true: when floodwater finds its way into a storage unit, the damage is often devastating—and frequently preventable.
The stories are too familiar. A small business owner loses irreplaceable inventory. A family discovers their photo albums turned to pulp. A facility manager faces thousands in liability claims after a single storm. The frustrating part? Most of this damage could have been avoided with the right preparation.
This guide breaks down exactly what both facility owners and renters can do to keep storage units dry. We'll cover practical solutions, from permanent infrastructure improvements to quick DIY fixes you can implement before the next storm rolls in.
Why Storage Unit Flood Protection Matters More Than Ever
Flooding is the most common and costly natural disaster in the United States [1]. And storage facilities—with their ground-level units, roll-up doors, and often minimal weatherproofing—are particularly vulnerable.
For facility owners, the stakes are significant. A single flood event can mean:
Damage claims from multiple tenants
Lost rental income during repairs
Potential liability issues
Reputation damage that drives customers elsewhere
For renters, the math is equally sobering. Most standard renter's insurance policies don't cover flood damage to stored items [2]. That means your vintage record collection, holiday decorations, or business inventory could be completely unprotected.
Climate patterns aren't helping either. Heavy rainfall events have increased in frequency and intensity across much of the country over the past several decades [3]. Flash floods can strike with little warning, and even facilities that have "never flooded before" are finding themselves underwater.
The time to prepare is before water reaches your door.
Common Ways Water Enters Storage Units
Before you can stop water, you need to understand how it gets in. Storage units are surprisingly vulnerable at multiple points.
Door Gaps and Seals
Roll-up doors are the biggest culprit. The gap between the bottom of the door and the concrete floor—even a quarter inch—is enough for water to pour through during heavy rain or flooding. Over time, rubber seals deteriorate, compress, or simply wear away. Standard weatherstripping often fails to create a truly watertight barrier against standing or flowing water.
Wall and Floor Penetrations
Older facilities may have cracks in concrete floors or gaps where walls meet the foundation. These become highways for rising groundwater or pooling surface water.
Roof and Ceiling Issues
Roof leaks might seem like a different problem than flooding, but the end result is the same: water-damaged belongings. Ponding water on flat roofs, clogged gutters, and failed flashing all contribute.
Drainage Problems
Improperly graded lots direct water toward buildings rather than away. Clogged drains can cause water to accumulate against unit doors. Even well-designed drainage systems fail if they're not maintained.
What Facility Owners Can Do: Infrastructure and Preparation
If you manage a storage facility, flood prevention is both a practical necessity and a competitive advantage. Tenants increasingly research disaster preparedness before signing leases. According to the Self Storage Association, properties that demonstrate proactive safety measures often see higher occupancy rates and tenant retention.
Conduct a Facility-Wide Water Vulnerability Assessment
Walk your property during and after a rainstorm. Watch where water flows, pools, and enters buildings. Document problem areas with photos and notes. This information guides your prevention investments.
Key areas to inspect:
Door seals on every unit (both drive-up access units and interior units)
Grading and drainage patterns across the lot
Roof condition and drainage systems
Foundation cracks or gaps
Gutter and downspout function
Upgrade Drainage Infrastructure
Proper drainage is your first line of defense. Ensure the lot grades away from buildings. Install or maintain French drains around building perimeters. Keep storm drains clear of debris.
Consider adding trench drains at building entrances where water tends to collect. These relatively affordable improvements can prevent significant damage.
Replace Worn Door Seals and Weatherstripping
Those rubber strips at the bottom of roll-up doors have a lifespan. When they're cracked, compressed, or missing sections, water walks right through. Budget for systematic seal replacement every three to five years—sooner in harsh climates or high-traffic areas.
Pro Tip: Standard storage unit weatherstripping is designed for dust and minor moisture, not standing water. For facilities in flood-prone areas, consider supplementing permanent seals with temporary flood protection measures during storm season.
Create an Emergency Response Kit
Storms don't wait for convenient timing. Assemble supplies that staff can deploy quickly:
Waterproof barrier tape (like FloodTape®) for sealing doors
Squeegees and wet vacuums
Sandbags or water-activated barriers
Portable pumps
Contact information for tenants
Having materials ready means the difference between quick response and watching helplessly as water enters units.
Communicate With Tenants
Proactive communication builds trust and reduces claims. Send seasonal reminders about flood preparation. Alert tenants when severe weather is forecast. Provide clear guidance on what they can do to protect their belongings.
What Renters Can Do: Protecting Your Stored Belongings
You might not control the facility, but you have more power over your unit's safety than you think.
Choose Your Unit Strategically
Location within a facility matters enormously. When signing a lease, ask about the facility's flood history. Request units that are:
Not in low-lying areas of the property
Away from visible drainage problem areas
On upper floors if available
In buildings with newer construction or recent weatherproofing
Climate-Controlled vs. Drive-Up Units: Interior climate-controlled units typically offer better protection from water intrusion than exterior drive-up spaces, though they're not immune to flooding. Drive-up units with roll-up doors are especially vulnerable at the door threshold. Consider the tradeoff between convenience and protection based on what you're storing.
Elevate Everything
Never store items directly on the floor. Plastic pallets, concrete blocks, or sturdy shelving create a crucial barrier between your belongings and any water that enters. Even four inches of elevation can save everything in a moderate flooding event.
Use Waterproof Containers
Cardboard boxes vs. plastic totes: There's no contest when it comes to flood protection.
Feature | Cardboard Boxes | Plastic Totes |
Water resistance | None – absorbs water like a sponge | High – seals out moisture |
Durability | Weakens when humid, collapses when wet | Maintains structure |
Stackability when wet | Collapses | Remains stable |
Cost | Lower initial cost | Higher but reusable |
Best for | Dry, short-term storage | Long-term or flood-prone areas |
Replace corrugated boxes with plastic totes with secure lids for anything water-sensitive. Waterproof bags provide additional protection for particularly valuable items like documents, photos, or textiles.
Seal Your Unit's Door
Most storage units have gaps around doors that standard weatherstripping doesn't adequately address. A waterproof adhesive tape designed for flood protection can create a temporary seal that keeps water out during storms.
FloodTape® works particularly well for this application. At 8 inches wide, it covers the gap between roll-up doors and floors completely. You can apply it quickly when storms threaten and remove it cleanly afterward—no residue, no damage to the door or floor [4].
Application is straightforward:
Clean the surface along the door base to remove dust and debris
Make sure the area is completely dry
Cut the tape to length and press firmly along the bottom of the door, covering the entire gap
Extend tape slightly up the sides where the door track meets the floor
Press firmly to create a tight seal
When removing the tape, pull back slowly toward you at a 45° angle or lower. This ensures clean removal without leaving residue on the door or concrete.
Get Appropriate Insurance
Standard tenant insurance through storage facilities often excludes flood damage. Review your policy carefully. Consider supplemental flood insurance if you're storing valuable items, particularly if the facility is in a flood-prone area.
The Hidden Threat: Moisture, Mold, and Humidity
Even if standing water never enters your unit, high humidity from storms can cause serious damage. This is a threat many renters overlook.
Why Humidity Matters
After heavy rain, humidity levels spike—sometimes dramatically. In a poorly ventilated storage unit, that moisture has nowhere to go. It settles on your belongings, creating conditions ripe for:
Mold and mildew growth on fabrics, paper, leather, and wood
Rust and corrosion on metal items, tools, and electronics
Warping and swelling of wooden furniture
Musty odors that permeate soft goods
Protecting Against Moisture Damage
For facility owners:
Ensure adequate ventilation in enclosed buildings
Consider dehumidifiers in climate-controlled sections during rainy seasons
Inspect units for signs of condensation after weather events
For renters:
Use moisture-absorbing products (silica gel packets, desiccants, or bucket-style moisture absorbers) inside your unit
Wrap fabric items in breathable cotton covers, not plastic (plastic traps moisture)
Leave space between items and walls for air circulation
Check on stored items periodically, especially after wet weather
Sealing your unit's door against floodwater also helps reduce humidity infiltration during storms—another reason temporary flood protection makes sense even when you're not expecting standing water.
DIY Flood Protection: A Step-by-Step Approach
Whether you're a facility owner preparing multiple units or a renter protecting your single space, this systematic approach helps ensure nothing gets missed.
Before Storm Season
Assessment Phase:
Walk the perimeter looking for drainage issues
Check door seals for wear, gaps, or damage
Inspect roof and gutters if accessible
Note any cracks in floors or walls
Preparation Phase:
Assemble protection supplies
Elevate stored items
Replace damaged weatherstripping
Clear drainage paths of debris
When Severe Weather Is Forecast
48-72 Hours Before:
Monitor weather updates
Review your emergency supplies
Alert tenants (if you're a facility owner)
Move particularly valuable items to higher positions
24 Hours Before:
Apply waterproof tape to vulnerable door gaps
Position sandbags or barriers if available
Ensure drainage is clear
Take photos of your unit's contents for insurance purposes
During the Storm:
Stay safe—don't visit the facility during dangerous conditions
Monitor conditions remotely if possible
After the Storm
Inspection:
Check for water intrusion before entering
Document any damage with photos
Contact facility management about any issues
Removal:
Remove temporary seals carefully
FloodTape® peels off cleanly when pulled slowly at a 45° angle
Clean and dry any surfaces that got wet
Restore normal ventilation
Real Scenarios: How Preparation Makes the Difference
Scenario One: The Unprepared Unit
Sarah stored her small business's seasonal inventory—about $8,000 worth of handmade crafts—in a ground-floor storage unit. A sudden thunderstorm dropped several inches of rain in two hours. Water seeped under the roll-up door, ruining cardboard boxes stacked directly on the floor. Her insurance didn't cover flood damage. Total loss: everything.
Scenario Two: The Prepared Unit
Mark stored similar inventory in the unit next door. His boxes sat on plastic pallets four inches off the ground. He'd applied FloodTape® along the door gap after checking the weather forecast. The same storm sent water to the building—but it didn't enter his unit. His belongings stayed dry.
The difference wasn't luck. It was a roll of tape, a few plastic pallets, and an hour of preparation.
Scenario Three: The Proactive Facility
A storage facility in coastal Florida invested in trench drains, maintains door seals annually, and stocks emergency supplies including waterproof tape for each building. When a major hurricane approached, staff sealed vulnerable units and alerted all tenants. Competing facilities in the area reported significant water damage and tenant losses. This facility? Zero units flooded.
Your Storage Unit Flood Prevention Checklist
Print this and keep it with your storage supplies.
Facility Assessment:
[ ] Door seals intact and functional
[ ] Floor free of cracks near doors
[ ] Drainage flowing away from unit
[ ] Gutters and downspouts clear
Unit Preparation:
[ ] All items elevated off floor
[ ] Waterproof containers for sensitive items
[ ] Waterproof tape on hand for emergencies
[ ] Valuable items positioned highest
[ ] Moisture absorbers in place
Before Severe Weather:
[ ] Weather forecast monitored
[ ] Waterproof tape applied to door gaps
[ ] Drainage paths cleared
[ ] Insurance documentation updated
[ ] Photos taken of contents
After the Storm:
[ ] Unit inspected for water intrusion
[ ] Damage documented with photos
[ ] Temporary seals removed properly (slowly, at 45° angle)
[ ] Surfaces dried and ventilated
Why FloodTape® Works for Storage Unit Protection
Not all waterproof tapes are created equal. Most duct tapes or generic waterproof tapes either don't create an adequate seal or leave a mess when removed.
FloodTape® was designed specifically for temporary flood protection. The 8-inch width covers standard door gaps completely [5]. The adhesive bonds to concrete, metal, and other common storage facility materials while still releasing cleanly when you're ready to remove it [4].
For facility owners, keeping a supply on hand means staff can quickly seal units when storms threaten—often faster than tenants can respond themselves. For renters, one roll provides enough material to seal a standard unit door multiple times.
The key advantage: it's truly temporary. Apply it when you need it, remove it when you don't, with no lasting marks or damage to worry about. It's easy to install and leaves no residue—exactly what you need for a storage unit you're renting.
Take Action Before the Next Storm
Flood damage to storage units isn't inevitable. It's preventable—with the right knowledge and preparation.
For facility owners, investing in drainage, maintenance, and emergency supplies protects your property, your tenants, and your business reputation.
For renters, a few simple steps—elevating belongings, using waterproof containers, controlling moisture, and sealing door gaps before storms—can mean the difference between dry possessions and devastating losses.
Don't wait for water at the door. The time to prepare is now.
Ready to protect your storage unit? Get FloodTape® today and keep your belongings safe from the next storm.
Frequently Asked Questions
How much gap under a storage unit door is enough for flooding to occur?
Even a quarter-inch gap can allow significant water intrusion during heavy rain or flooding. Water under pressure—from pooling or flowing floodwater—forces its way through surprisingly small openings. Standard roll-up doors often have gaps of half an inch or more, especially as seals age and compress. Sealing these gaps with waterproof tape before storms can prevent thousands of dollars in damage.
Can I use regular duct tape to seal my storage unit door?
Regular duct tape isn't designed for flood protection and typically fails in two ways. First, it doesn't create a truly waterproof seal, especially on textured surfaces like concrete. Second, it leaves sticky residue that's difficult to remove and can damage surfaces. Purpose-built flood protection tape like FloodTape® creates a stronger seal and removes cleanly without residue.
How often should facility owners replace door seals on storage units?
Door seals should be inspected annually and replaced every three to five years under normal conditions—sooner if visible damage, cracking, or compression is evident. Facilities in harsh climates or those with heavy use may need more frequent replacement. Proactive seal maintenance is far less expensive than water damage claims.
Does renter's insurance cover flood damage to items in storage?
Most standard renter's insurance policies and facility-offered protection plans exclude flood damage specifically [2]. Review your policy carefully or speak with your insurance provider. If you're storing valuable items in a flood-prone area, supplemental flood insurance through the National Flood Insurance Program or private insurers may be worth considering.
How long can FloodTape® stay applied to a storage unit door?
FloodTape® can remain applied for up to 14 days when used as directed. For storage unit applications, it's best used as temporary protection before and during storm events, then removed once the threat has passed. Always remove the tape by pulling back slowly at a 45° angle or lower to ensure clean removal without residue.
About This Guide
This article was developed by the FloodTape® team, drawing on extensive experience in flood prevention and protection. FloodTape® was invented by Matthias Herzog after 15 years of living in hurricane-prone St. Augustine, Florida, where he personally tested countless flood protection methods. Our recommendations combine practical field experience with current best practices in water damage prevention. For questions about protecting your storage facility or unit, contact us at contact@myfloodtape.com.
Cited Works
[1] Federal Emergency Management Agency — "Flood." https://www.fema.gov/flood
[2] Insurance Information Institute — "Understanding Flood Insurance." https://www.iii.org/article/understanding-flood-insurance
[3] U.S. Environmental Protection Agency — "Climate Change Indicators: Heavy Precipitation." https://www.epa.gov/climate-indicators/climate-change-indicators-heavy-precipitation
[4] FloodTape® — "FAQs for FloodTape®." https://www.myfloodtape.com/faq
[5] FloodTape® — "Simple DIY Flood Protection Tape."
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