How to Build a Flood Wall Around Your House

Jessica Stone
by Jessica Stone
Homes built in flood plains or climates with frequent rain can benefit from a flood wall, but it’s not always clear how to build one. Flood walls can take the brunt of excess water and protect your home from damage, and they range from preconstructed walls to earthen levees. Whether it be digging a hole, constructing a mound, or preparing the site, let’s take a look at the factors involved in building a flood wall.

Whether you’re a prepper by nature or not, you should always be prepared in the instance a flood should occur and threaten to damage your home. While you can certainly purchase the right insurance and stock up on necessary supplies, the post-flood cleanup and having to replace your treasured family belongings are not worth the energy.

Flooding is considered to be the number one natural disaster in America, necessitating that you should be looking at implementing a flood wall to keep your home safe. In general, you should never ignore the evacuation orders when a flood is approaching.

However, with a little bit of time and the proper materials, you can construct a successful flood wall that will keep your home safe from rising floodwaters. These practices include building your very own earthen levee or coming prepared with various types of pre-constructed, self-rising flood walls that involve very quick installation.

If you live in an area of the world that is susceptible to flooding, it’s essential that you are fully equipped to defend your home. Let’s examine all the actions you can take to build a flood wall around your house and effectively keep your property dry.

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Building an Earthen Levee

If it’s an emergency, you may have no other option that building a flood wall using the dirt underneath your feet. Here are all the steps involved in constructing your very own earthen levee.

1. Gather All the Necessary Materials

For this project, all the basic materials you’ll need are shovels, sand bags, gloves, and a wheelbarrow. There are other items that may be helpful but will likely be hard to acquire in a time crunch.

While we understand most often the reason for building a flood wall with the dirt from your property typically means it’s a severe emergency, if you have the time for choices, try to opt for a soil that is finer-grain. Sand or clay are better options that the larger alternative. Coarser materials like gravel have gaps between the particles that can allow water to seep through.

2. Project Site Prep

The route of your flood wall will depend on your property’s terrain topography and overall expanse. Whichever way you decide to lay out your earthen levee, make sure that you leave a sufficient amount of space between your home and the barrier.

If needed, this will give you the opportunity to build the barrier wall wider and higher. In order to properly prep the area, clear the topsoil and, if time permits, bushes and other material.

3. Dig a Trench

Instead of just piling up dirt onto a barren area of land, you’ll want to build a trench firs t. Dig a one- or two-foot trench in the planned location of your levee. Fill up this hole with the most impermeable material you have, such as clay or sand, to establish a foundation.

A small foundation helps to reduce the likelihood of water seeping under the levee and causing a collapse. Another way to limit underseepage is to install a “cutoff wall” several feet below ground. Concrete walls are always the best option but when you’re under a time constraint, you can try burying particle board and compacting soil around it.

4. Build the Dirt Mound

Once your foundation has been established, begin shoveling sand, clay, soil or whatever material is available onto the line where your barrier wall will stand. For this step, sufficient compaction is essential. If you do not possess heavy machinery for the job, use your hands or feet.

Press down on the levee in sections of 6 inches as you build, instead of compacting a mound that is several feet high at the end. Construct a levee that is relatively flat, as steep slopes will offer an additional buffer for water penetration.

Your barrier wall is recommended to be roughly three times as wide as it is tall. If you have the space, the top of the levee should be several feet wide. Factor in the floodwater crest estimates and aim to build a level that is a few feet higher.

5. Cover Your Barrier Wall

If you have the materials, cover the side of your levee that will face the water with plastic tarping. When in place, plastic tarps will provide an extra layer of imperviousness, increasing the wall’s lifespan and slowing down erosion.

We recommend anchoring the tarps in the front of the flood wall and securing on the top using sandbags. However, if you do not have enough sandbags readily available to cover the size of your property, you can run rope between two of them on either side of the all wall to secure the tarps.

6. Contain Sand Boils

If you’re still on property as the flood waters are rising, you can perform some maintenance to ensure that the levee stays resilient. The main concern for this earthen levee will be sand boils, that appear like bubbling springs on the home side of your barrier.

Significantly high floodwater levels put pressure on groundwater and can force it underneath the barrier wall. This can cause the levee’s foundation to be weakened and if the flowing water is sandy, instead of clear, this means the water is carrying away the foundation material.

When you have sand boils present, your best course of action is to surround it with sandbags or build a mini barrier wall around it. The small levee will create a pooling effect and once it’s full, the flow of the sand boil will halt.

Self-Rising Flood Walls

If you are not under a time crunch and are just looking to be fully prepared should a flood ever come, consider purchasing a self-rising flood wall. There are a number of devices on the market that can aid in flood protection. These include:

  • A Flood Barrier. This is a water-activated flood barrier that is simply laid out to put in place. It will rise on its own once it comes into contact with water. In less than ten minutes, these flood walls can grow up to 3.5 inches high. This product is also stackable to add extra height and can be joined together for added length and protection against floods. They can be purchased in 5-foot, 10-foot and 17-foot lengths.
  • Quick Dam Flood Bags. These are constructed of the same material as the aforementioned flood barrier and will also rise within ten minutes when introduced to water. Pre-constructed flood bags save you from having to rely on conventional sandbags and needing to fill them up with sand. They are also stackable to have enough height for a doorway or wall gap and come in packs of 2, 6, 20 and 120.
  • Water-Gate. These self-rising Water-Gate flood walls are constructed to work with large floods and high flood waters. Although they are pretty expensive, they are worth the investment for defending your home against flooding. They are designed for use with water levels from 6 inches to five feet high and can be joined together on either side.

Other Ways to Protect Your Home Against Flood Damage

In addition to building a flood wall around your property, there are a number of other steps that can be taken to protect your home from flooding. These include:

  • Add a waterproof veneer to the exterior walls. A home’s interior can still be severely damaged in a flood, even when the floodwaters are less than two feet deep. To safeguard against shallow flooding, implement a waterproof veneer such as a layer of brick with a waterproof backing.
  • Choose flood-resistant building materials. Building materials are deemed flood-resistant if they can endure direct contact with flood waters for at least 72 hours without becoming considerably damaged. Some of these include ceramic tile, concrete, pressure-treated and marine-grade plywood, and closed-cell and foam insulation.
  • Secure your fuel tanks. When you have unanchored fuel tanks, it’s very easy for floodwaters to uproot them and cause serious problems. One way you can anchor a fuel tank is to secure it to a large concrete slab that is heavy enough to withstand the force of floodwaters.
  • Install back-flow valves to protect your home from sewage backups. Flooding can cause the sewage from sanitary sewer lines to backup into your home from the drainpipes. These backups not only create damage that is challenging to repair, it also presents a health hazard.
  • Move your HVAC equipment to the upper levels of your home. Your HVAC equipment, such as a water heater or furnace, can become badly damaged if floodwaters reach it. To protect these units, move them from the basement or lower level to an upper level in your home or even an attic. Alternatively, you can leave the HVAC equipment in place and construct a flood-proof wall around it.

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Wrapping It Up

Doing your research, planning ahead and knowing exactly how to build a flood wall can help you save your home in the case of a major flood. Whether you decide to purchase a self-rising flood wall or construct one using the earth found in your yard, you will significantly reduce the likelihood of damage to your property.

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Jessica Stone
Jessica Stone

Jessica considers herself a home improvement and design enthusiast. She grew up surrounded by constant home improvement projects and owes most of what she knows to helping her dad renovate her childhood home. Being a Los Angeles resident, Jessica spends a lot of her time looking for her next DIY project and sharing her love for home design.

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