How to Build a Flood Wall Around Your House

It’ll take some serious digging, but it’s worth the effort for your peace of mind

Young woman sweeping water from front yard on rainy day
Photo: freemixer / E+ / Getty Images
Young woman sweeping water from front yard on rainy day
Photo: freemixer / E+ / Getty Images
SKILL LEVEL
Challenging
COMPLETION TIME
10 hours
COST
$500–$1,000
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What you'll need:
TOOLS
  • Shovel
  • Wheelbarrow
  • Trench digger
  • Tamper
SUPPLIES
  • Gravel
  • Pebbles
  • Sand
  • Soil
  • Heavy-duty plastic covering

Buying a home comes with a host of maintenance tasks. Buying a home in a flood zone has an even greater set of responsibilities if you want to protect it in inclement weather. A flood wall is one way to protect your home from serious water damage. This guide will walk you through the strenuous task of building a flood wall around your house to keep water from infiltrating your home.

Prepping to Build a Flood Wall

Digging a trench using a shovel
Photo: tinabelle / iStock / Getty Images

As you might expect, learning how to build a flood wall around your house is not a relaxing, easy weekend DIY, like painting an accent wall. It’s far more serious and labor-intensive than that. A flood wall secures your home—not to mention the people living in it—from rising floodwaters, saving you potentially thousands in damage repair costs.

Because it’s so important, this complex project is best left to professionals who can gather building permits (which may or may not be needed depending on where you live) and who already have the heavy-duty equipment to make this project quicker and easier. If you have a lot of experience in this field and access to otherwise expensive tools, you may be able to use the following steps to learn how to build a flood wall around your house.

  1. Clear the Area

    You are about to do a lot of digging, so you’ll need space to put the discarded soil that will accumulate. Do not discard or use this soil elsewhere in your yard—you’ll need it again soon enough.

  2. Start Digging a Trench

    Mark off where you’d like your flood wall to be, then start digging a 2-foot trench. The trench needs to be deep enough to create a sturdy base to hold whatever filler you’ll be using, so be sure that you’ve got a trench digger and not just an ordinary shovel on hand.

  3. Fill the Trench

    Start pouring in sand, rocks, pebbles, gravel, and other fillers. Sand fills the trench quickly, but denser materials like rocks will work harder to protect your foundation from floodwaters.

  4. Build a Dirt Mound

    Build a mound using the soil from when you dug the trench. Pack down the dirt as you add a new layer—the more, the merrier when it comes to adding layers of dirt. Use a tamper for the best results. Depending on how high you build the mound, you may want to use a mechanical tamper rather than a manual one.

  5. Cover the Mound

    Once you’ve raised the mound to the desired height, cover it with water-resistant plastic. Then, add sandbags, extra dirt, and rocks as needed to keep everything in place.

    Provided you have time before the floodwaters start to rise, you may also consider adding the following to augment your flood wall:

    • Water-activated flood barriers: These can rise up to 3 1/2 inches as water starts to rise.

    • Flood bags: These will also rise up in the presence of water to make your flood wall work even better.

    • Self-rising water gates: These self-activated dams are an expensive addition, but they could be well worth it if you live in a flood zone.

Additional Considerations for Building a Flood Wall

If you decide to build a flood wall to protect your home from rising waters, there are a few additional considerations to account for before you grab your shovel.

Check Local Zoning or Codes 

If you hire a professional to build your flood wall, they’ll likely take care of this for you, but it never hurts to do the research on your own or do some double-checking. You may need a permit to construct a flood wall, but it will ultimately depend on your local building permit requirements. The cost also varies by your location and the type of permit you need.  

Avoid Redirecting Water to Another Property 

When you build a flood wall to protect your property, the last thing you want to do is compromise neighboring properties by redirecting the floodwater toward them. To avoid this, your contractor will ensure the mound is sloped correctly so that it won’t compromise other properties.

Check Your Flood Insurance 

If you live in a flood-prone area, you’ll likely have flood insurance, but check with your flood insurance company to see exactly what is covered. Ask if building a flood wall will lessen your premiums or if they offer any other benefits or incentives to build one.

DIY vs. Hiring a Pro 

If you’ve got the time, tools, energy, and strength—and hopefully some helpers, too—to dig and fill a trench around your home, you might be able to get it done. But if there ever was a time to save your DIY skills for another project, building a flood wall would be it.

While any amount of precaution in the face of a storm is a good thing, an extensive project like building a flood wall around your house could be a disaster if not done correctly—though arguably not as disastrous as rising floodwaters can be.

Labor costs will increase the overall price of any home improvement project, but having a flood wall done right the first time can save money down the road. As cliché as it may sound, it’s truly priceless to enjoy the peace of mind knowing that your flood-prone home is protected. Contact a basement waterproofing company in your area that can provide guidance and complete your flood wall project.

Frequently Asked Questions

The best way to ensure the ground next to your home’s foundation drains properly is to divert water away from it as much as possible. While a flood wall can stop water from entering the house, gutters and spouts can help direct rainwater and melting snow away from the foundation. Keep your gutters as clear as possible from dead leaves and other yard debris so they can effectively divert water from your house. Add extenders to the spouts so the water runs out and away from your home, not into the surrounding soil.

The soil around your foundation should slope down and away from your home, not toward it. If the grading drops the farther you are from your home, you can enhance the slope by removing more soil. Mark off a few feet from your house and dig up some of this soil. Regrading around your fountain should encourage water to flow away from your home and not collect or “pond.”

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