Using Sandbags for Flood Protection During Tropical Weather

As we prepare for incoming tropical weather, protecting your home from floodwaters becomes a top priority, especially for those living in flood-prone areas. Using sandbags for flood protection is a commonly used and cost-effective method to provide a temporary barrier against rising waters.

Thankfully, many municipal governments offer free sandbag stations ahead of storms. In Polk County, residents can collect up to 10 sandbags, which is usually enough, along with a plastic water barrier, to protect two standard-sized doors. See current information from Polk County’s Emergency Management Facebook page about sandbag stations.

While sandbags can be an essential part of your storm preparation, it’s important to remember that they’re only part of a larger flood protection strategy.

If your home has experienced minor water intrusion from one or two doorways, ten sandbags may be enough to help protect your home.
If your home has experienced flooding from all sides in prior tropical systems, ten sandbags may not be enough to protect your home. Before a named storm is expected, create your flood protection plan.

How Sandbags Work

Sandbags, when filled and stacked properly, can help hold back floodwater. They work best when paired with polyethylene sheeting (a heavy-duty plastic), which helps improve their effectiveness. Sandbags and a tarp are a good way to divert floodwaters, but both must be used correctly to work.

LSU Extension provides detailed guidelines on sandbagging, including how to stack them and how to incorporate plastic sheeting for better flood defense.

Additionally, sandbags must be properly placed to protect your home from water damage. When set up correctly in front of doors, they can help keep minimal floodwaters and debris away from your home. For more information, you can also visit the Hillsborough County Government’s guide on sandbagging a door.

Considerations Before Sandbagging

While sandbags are often provided free of charge by local governments, the labor of filling, carrying, and stacking them can be stressful, physically challenging, and time-consuming. For those who have only a few hours to prepare before a storm, setting up a sandbag defense can be a race against time. This means planning ahead is essential.

If you plan to rely on sandbags but need more than our local government provides, stockpiling sand ahead of time on your property can save precious hours during storm prep. The sand should be relatively free of gravel and covered to prevent erosion or contamination.

Filling and Stacking Sandbags

Fill sandbags halfway to two-thirds full. Overfilling them makes stacking difficult and leads gaps in the sandbag wall that water can flow through.
There’s no need to tie the bags. Simply twist and tuck the top of each bag under so the bag seals with its own weight.
Bring a friend to the sandbag distribution site. If the site does not have a sandbag machine and requires you to fill your own, it is a two-person job. One person should hold the bag while the other fills it with sand.
If the sand is very dry, safety goggles may be helpful to protect your eyes from dust.

Setting up Sandbags and a Tarp to Divert Water

To protect your home as much as possible, place a plastic tarp in front of the flood-prone door. The tarp will serve as a liner and is an essential step, as sandbags alone won’t seal off or stop floodwater.

A doorway is blocked by a tarp which is taped to the wall with water-resistant tape. On the tarp, seven sandbags are stacked like bricks with overlapping seams. The sandbags have been flattened to fill all available space infront of the door and keep the tarp in place. — This image, from Hillsborough County Government, shows how to properly sandbag and tarp a doorway to minimize flood damage.

Follow these steps:

Ensure the tarp reaches higher than the expected flood level and extends underneath the row(s) of sandbags.
Affix the tarp to the door and doorframe with heavy-duty waterproof tape to secure it in place.
Place the first row of sandbags horizontally across the doorway, making sure they’re flush with the exterior of the house. Flatten the bags as tightly as possible against the house and door.
If more than one row is needed, stack the next row on top of the first in a staggered formation, similar to bricks in a wall. Continue flattening and securing the sandbags as you go.
Seal any cracks between the bags by pressing them down with your feet to ensure the best possible protection.

If you do not have a tarp or access to 6mil plastic sheeting (often sold at local home improvement stores) – look for contractor trash bags. When cut into a flat sheet they may be large enough and thick enough to act as an emergency tarp and protect your home, under the sandbags.

Building Sandbag Levees

If you need protection from water deeper than two feet, you’ll want to create a levee-like structure using many sandbags. Learn more about building a levee system here, from LSU Extension.

Fortunately, the need for this level of protection is rare in our part of Florida.

Sandbagging Tips

Be sure you have enough time to set up your sandbag barrier before the storm hits.
Keep materials on hand, including sand, sandbags, a shovel, polyethylene sheeting, and waterproof tape or caulk.
Plastic sheeting will improve the performance of any sandbag barrier.
Even the best systems can leak; have a pump ready to remove water that seeps in, if you’re expecting flood water.
Always have an evacuation plan. If the situation worsens, your safety should always come first.
After the storm, stack your sandbags in a high, dry place to keep them for future storms. Stored in a garage and kept dry, sandbags should last a year or more.

When to Evacuate

In areas expecting major flooding, sandbags can offer some temporary protection, but they are not a guaranteed solution, especially in the face of severe storms. If local authorities recommend or order evacuation, it’s important to heed those warnings.

While protecting your home is a priority, your safety and that of your family should come first. Have an evacuation plan in place, and decide in advance when it’s time to leave. A well-prepared flood defense can give you peace of mind, but personal safety always takes precedence over protecting property.

If you need additional information on forming an emergency plan, UF/IFAS Extension has a disaster website and guide you may find useful. Find that guide, here: https://disaster.ifas.ufl.edu/

For more information on how to use sandbags for flood protection, check out the detailed guides from LSU Extension and Hillsborough County Government.