What sandbags can (and can’t) do in a Houston storm
Sandbags are a temporary flood protection tool. They’re great for slowing shallow flood water and steering runoff away from doorways, garage doors, and low spots at ground level. They’re not a cure-all. If water rises fast, if your home sits lower than the street, or if water pressure builds against a long wall, sandbags may reduce seepage but won’t stop it completely.
As water damage restoration professionals in Houston, we’ve seen both outcomes. We’ve walked into homes where a clean, well-built sandbag “wall” kept water out of a front entry during heavy rain. We’ve also seen sandbags stacked like a tower—too tall, too narrow—then slump and let water through within an hour.
Used correctly, sandbags can:
- Reduce water intrusion at common entry points
- Divert water away from a doorway threshold
- Slow down seepage long enough to move valuables and shut down power safely
Used incorrectly, they can:
- Create gaps that funnel water inside
- Collapse under their own weight
- Trap water against siding or brick, increasing seepage through weep holes
Houston-specific realities: why placement matters more here
Houston hurricane season is its own animal. We get intense bursts of heavy rain, flat terrain, and drainage systems that can be overwhelmed fast—especially in neighborhoods near bayous, older storm sewers, or low-lying subdivisions.
A few local factors that change how we approach sandbagging:
- Clay-heavy soils (common across much of the metro) don’t absorb quickly. Surface water sheets across lawns and driveways, then collects at doorways.
- Slab-on-grade homes often have entry thresholds close to ground level. Water doesn’t need to be deep to get inside.
- Pier-and-beam homes can have vulnerable foundation vents and crawlspace openings. Flood water under the home is a different kind of problem.
- Driveway slope toward the garage is a frequent culprit. We’ve measured garages that sit 2–4 inches lower than the driveway crown—enough to invite water.
So yes, sandbags help. But in Houston, the “where” is often more important than the “how many.”
Materials you’ll want on hand (before the rain starts)
You can build a solid barrier with basic supplies, but don’t improvise at the last minute. The storm won’t wait.
Sandbagging kit:
- Sandbags (polypropylene bags are common)
- Sand (clean fill sand works; avoid debris-heavy soil)
- Shovel (a square-point shovel is easier for filling)
- Wheelbarrow or garden cart
- Work gloves
- Plastic sheeting (6 mil is a practical thickness)
- Duct tape (for anchoring plastic at thresholds)
- Utility knife or scissors
- Push broom (for cleaning the ground where bags will sit)
A simple but often-missed item: a tamping tool. We’ve used a hand tamper, a short 2x4, even the flat back of a shovel. Tamping matters because it helps the bags mold together and cuts down on channels where seepage starts.
Where can I get sandbags in Houston?
People ask this every season. The honest answer: it depends on the storm, the city’s readiness level, and where you live.
During major weather events, local agencies sometimes set up sandbag distribution sites. These may be run by the City of Houston, Harris County, or specific municipalities (like Pasadena, Pearland, or others). Availability can change quickly, and lines can be long.
What we tell homeowners we work with:
- Check your city or county emergency management updates before you drive.
- Bring your own shovel and bags if the site is “sand only.” Some sites provide filled bags; others provide bulk sand.
- Go early. Distribution sites can run out.
If you can’t find a public distribution site, many landscape supply yards and some home improvement stores sell bags and sand.
Choosing the right locations: identify your home’s entry points
Before you fill a single bag, walk your property the way water would. Start at the street. Look at slopes. Notice where puddles form during normal rain. Those are your clues.
Common entry points we see during flood damage cleanup calls in Houston:
- Front and back doorways (especially with worn weatherstripping)
- Garage doors (bottom seal gaps, uneven slabs, or settlement cracks)
- Sliding glass doors (tracks sit low and clog easily)
- Side gates and fence lines that funnel water toward a door
- Foundation vents on pier-and-beam homes
- Low wall penetrations (hose bibs, old cable pass-throughs)
A practical approach: prioritize the lowest openings first. If you only have time for one area, protect the most likely place water will cross your threshold.
Do you put plastic under sandbags?
Usually, no—at least not under the entire stack. Here’s why. Sandbags work because the sand conforms to the surface and to the next bag, creating a dense, heavy barrier. If you lay plastic sheeting underneath the bags, you can reduce friction and create a slip layer. We’ve seen stacks creep and shift on smooth plastic when water starts pushing.
Where plastic sheeting does help is as a water-shedding layer:
- Place plastic sheeting on the water side of the sandbags (like a raincoat), extending outward toward the flood side.
- Run the plastic up against the base of the door threshold or wall.
- Then set the first course of sandbags on top of the bottom edge of the plastic to hold it down.
This setup helps divert water and reduces seepage through the sandbag wall. Think “apron,” not “skateboard ramp.”
How full should a sandbag be?
About half to two-thirds full. The Federal Emergency Management Agency notes that sandbags should be filled only partway so they can be shaped and stacked tightly to form an effective barrier. According to FEMA, overfilled bags don’t conform well and are harder to seal when you stack them.
That surprises people. They want to stuff them like pillows. Don’t. A properly filled sandbag needs slack so it can flatten, fold, and seal against the next bag. Overfilled bags stay round, which creates gaps and channels—exactly where flood water sneaks through.
In our experience, the sweet spot is:
- 50% full for easier shaping (great for doorways and uneven surfaces)
- 60–65% full if you need a slightly heavier bag for stability
Tie-off: you can tie the bag, but don’t leave a big “tail” sticking out on the flood side. Fold it under the bag if possible.
How to fill sandbags quickly (without wrecking your back)
Filling is where most DIY sandbagging loses time.
A method our team uses when helping families prep:
- Set the bag in a bucket or a wide-mouthed trash can to hold it open.
- One person shovels sand. One person holds and moves bags.
- Fill to half or two-thirds.
- Fold the top down (or tie it), then stage bags near the build location.
Pace matters. A steady rhythm beats frantic shoveling.
Stacking sandbags: the pattern that actually works
Stacking sandbags isn’t about building tall. It’s about building tight.
The best pattern: interlocking “brick pattern”
Use an interlocking pattern (also called a brick pattern) where each bag overlaps the seams of the layer below it.
- Lay the first row lengthwise, tight together.
- Place the second row so the bags sit over the joints below (like bricks).
- Keep the wall as low and wide as possible.
Then tamp down each layer. Not optional.
How high should you stack sandbags for flooding?
For most residential situations, stack 2 to 3 layers high. Why not higher? Stability.
A practical rule our experienced technicians follow:
- Base width should be about 3 times the height for a stable stack.
- If you go taller without widening the base, the wall slumps. Water pressure finds the weak spot.
Typical heights:
- 2 layers: good for shallow street runoff and minor pooling
- 3 layers: better for driveways and patio doors where water can build
If you think you need 4+ layers, pause and reassess. You may need to redirect water farther upstream (driveway berm, temporary drain channel, or additional barriers) rather than stacking a narrow sandbag tower.
The “pyramid” shape for stability
For doorways and straight runs, build a small pyramid:
- 1st layer: widest
- 2nd layer: slightly inset
- 3rd layer: inset again
This shape resists sliding and helps the wall hold when water pushes.
Step-by-step: sandbagging doorways the right way
Doorways are the most common “we thought we were fine” failure point.
- Sweep the ground clean. Mud, leaves, and gravel create gaps.
- Lay plastic sheeting on the flood side, with the bottom edge extending out 12–24 inches.
- Place the first course of sandbags over the bottom edge of the plastic. Bags should run parallel to the threshold.
- Tamp the bags down to flatten them and seal the seams.
- Add a second course in a brick pattern. Offset the joints.
- Seal the ends. Water loves to run around the side of a barrier. Extend the wall 12–18 inches beyond the doorway on both sides if you have room.
For sliding glass doors, build the same barrier but pay extra attention to the track area. Tracks collect grit; once clogged, they can hold water right against the door frame.
Step-by-step: protecting garage doors (where water builds fast)
Garage doors are tricky. The opening is wide, slabs can be uneven, and water can build deep along the driveway.
What we do in real homes:
- Start by checking the bottom seal. If it’s torn or missing, sandbags are doing all the work.
- Identify low points along the slab edge. Many garages dip near the center.
Build plan:
- Clean the driveway edge and garage threshold.
- Lay plastic sheeting on the driveway side, running the length of the door.
- Place the first row of sandbags tight to the door line.
- Add a second row in a brick pattern.
- If you have enough bags, add short “returns” up both sides of the garage opening to reduce end-run water.
One more tip from the field: if the driveway slopes toward the garage, consider placing a second, smaller line of sandbags several feet up the driveway to slow and divert water. Two barriers with space between them can outperform one tall wall.
Slab foundation vs. pier-and-beam: sandbagging changes by home type
Houston has both, and the strategy isn’t identical.
Slab-on-grade homes
Most water intrusion happens at doorways, garage doors, and wall penetrations near ground level.
Priorities:
- Doorways (front, back, side)
- Garage doors
- Sliding glass doors
- Low exterior vents or weep holes where water pools
Watch for seepage through brick weep holes. If water is held against the wall by sandbags, it can migrate inward. That’s where plastic sheeting as an apron helps—divert water away from the wall face.
Pier-and-beam homes
The goal often shifts to keeping flood water out from under the home.
Priorities:
- Foundation vents
- Crawlspace openings
- Low access doors
Sandbags can be placed around vent openings, but don’t block airflow for long periods if conditions are dry later. Moisture trapped under a home can lead to microbial growth; the Centers for Disease Control and Prevention warns that damp indoor environments can promote mold growth after flooding and water intrusion. According to the CDC, prompt drying and moisture control are key to reducing mold and related health risks.
Also: if water is already rising around the perimeter, sandbagging individual vents may not be enough. A perimeter approach can take a lot of bags and time, and you may ultimately need crawl space water removal if water collects under the home.
Common sandbag mistakes we see after storms
After helping hundreds of customers with water damage across Houston, these are the recurring issues:
- Overfilled bags that won’t flatten
- No tamping down, leaving channels between bags
- Stacking too tall without widening the base
- Not extending past the doorway, letting water run around the ends
- Placing bags on debris, creating gaps from the start
- Waiting too long. Once water is flowing, placement becomes harder and riskier
A small detail with big consequences: leaving the stitched side of the bag facing the flood. If the seam fails, the bag slumps. We typically orient seams away from the main push of water when possible.
What to do if water still gets in
Sometimes you do everything right and still get seepage. Houston storms can push water sideways, up through slab cracks, or in through hidden paths.
If water enters:
- Keep people safe first. Avoid wet electrical areas.
- Move valuables up off the floor.
- Use towels to slow spread at interior doorways.
- If you have a wet/dry vacuum, remove water early—standing water soaks baseboards fast.
Need help? Call Houston Water & Fire Damage Restoration Pros at (833) 569-1731 or request emergency water removal in Houston. Our emergency-water-removal crews see the difference early action makes.
Based on industry standards, timely extraction and drying help limit secondary damage (like material swelling) and reduce the chance of microbial growth. The IICRC provides the widely used S500 Standard and Reference Guide for Professional Water Damage Restoration.
Can you reuse sandbags after a flood?
Sometimes, but be picky. If sandbags were exposed to flood water, treat them as contaminated. Flood water can carry bacteria, fuel residue, and chemicals from roads and yards.
In our experience:
- Reuse is reasonable if the bags stayed clean and dry (stored indoors, unused, or only exposed to clean rainwater).
- Reuse is not recommended if the bags sat in flood water, touched sewage, or were in contact with oily runoff.
Also, many bags degrade in sun and heat. If the fabric is brittle or tearing, don’t count on it next season.
After the storm: handling and disposal in Harris County
Disposal rules can change after major events, and local guidance may be issued for storm debris.
Practical, safety-first steps our team follows and recommends:
- Wear gloves and closed-toe shoes when handling used sandbags.
- Let bags drain and dry in a contained area if possible.
- Don’t dump sand into storm drains. That can clog the system and worsen neighborhood flooding during the next heavy rain.
- Check local instructions for storm debris drop-off or pickup. Harris County and the City of Houston may provide specific directions after widespread flooding.
If you suspect contamination (strong odor, visible sheen, sewage exposure), bagging and disposal should be handled carefully. When in doubt, treat it as contaminated material and consider professional sewage cleanup support if backups were involved.
Extra flood protection steps that pair well with sandbags
Sandbags work best as part of a simple plan.
- Clear gutters and downspouts. A clogged downspout can dump roof water right at a doorway.
- Extend downspouts 4–6 feet away from the home if you can.
- Check yard grading near the foundation. Even a small low spot can hold water against the wall.
- Inspect weatherstripping and door sweeps before hurricane season.
- Keep a small pump on hand if your area floods frequently.
We’ve also seen big wins from basic maintenance: sealing cracks at ground level, keeping drains clear, and making sure the garage door seal actually contacts the slab.
After heavy storms, pairing sandbagging with professional storm damage restoration can help address roof, siding, and interior water issues together.
FAQ
Below are the most common sandbag questions we hear in Houston every hurricane season.
How high should you stack sandbags for flooding?
Most homes do well with 2 to 3 layers, built wide and tamped down. Taller stacks often slump unless the base is widened significantly.
Do you put plastic under sandbags?
Typically, place plastic sheeting on the flood side as an apron to shed water, then hold it down with the first row of sandbags. Avoid placing plastic directly under the whole stack because it can reduce grip.
Where can I get free sandbags in Houston?
Availability varies by event. During major storms, local agencies sometimes open sandbag distribution sites. Check your city or county emergency management updates for locations and hours.
How full should a sandbag be?
Fill sandbags about half to two-thirds full so they flatten and seal in a brick pattern. Overfilled bags stay round and leak at the seams.
Can you reuse sandbags after a flood?
Only reuse bags that stayed clean and dry. If bags contacted flood water, especially sewage or roadway runoff, treat them as contaminated and dispose of them based on local guidance.
If hurricane rain leaves you with water damage
Even with good sandbagging, Houston storms can push water into homes through hidden paths—under siding, through slab cracks, or around garage doors.
Our team at Houston Water & Fire Damage Restoration Pros handles water damage restoration across Houston, flood damage cleanup, and related services like mold remediation if moisture lingers after a storm.
If you need help drying out, documenting damage, or preventing further spread, call (833) 569-1731 and we’ll talk through next steps.