Tools and Materials
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About Sand Bags for Flooding
Sandbagging is a flood prevention technique that has been around for centuries. You can build a barrier with sand bags to help divert and stop water from getting inside vulnerable doors and around foundations.
Sandbagging can be done with traditional sand bags — the most recognizable of which is burlap. There are also other products on the market, such as self-inflating bags, which act as flood barriers that are easier than sand bags to maneuver. Regardless of the type of bag you use, the same tips and techniques for placement apply.
How Long Can Sand Bags Last?
A sand bag can last indefinitely. The bags are durable, and sand never breaks down or evaporates. Sand comes from rock and melts only at extreme temperatures — making sand a substantial and reliable choice for flood and erosion control. Burlap and nylon bags are stitched, making them highly tear-resistant. While penetrable to water the sand inside should mostly make up for this flaw.
What Are the Advantages and Disadvantages of Sand Bags?
One advantage to using sandbags is that resources are plentiful and inexpensive — especially if you already have sand. The tradeoff is that it requires time and effort to put together an effective sand bag barrier. And should holes develop, water could enter the bag and sand could leak out.
Should Sand Bags Be Inside or Outside?
Sand bags always need to be placed outside the home or building. Having a flood barrier indoors will still permit water inside the home, so always place bags in the way of a door or entryway for the best chance of flood control.
What's the Best Material to Fill Sand Bags?
Sand is the go-to material, but sandy soil is a viable alternative. Sand can potentially leak through loosely woven or stitched bags; it's best double-bag. Rocky soil or gravel is another sturdy option, although they won't help much to repel water on their own. Avoid leaking materials entirely with inflatable barriers.
How to Use Sand Bags
Traditional sand bags are an effective way to deflect water and help protect structures from flooding. Sand bags can be made of burlap, polypropylene, polyethylene and nylon. Any of these materials will suffice for sand bags, though nylon bags are coated with urethane for added water resistance, and they use double-stitched seams for increased durability. Consider nylon for a strong synthetic material that has minimal chance of tearing and leaking.
Before starting, determine how high you want the sand bag wall to be. Measure the length of your bags to help you determine the number of sand bags you’ll need.
How to Use Self-Inflating Flood Barriers
Self-inflating flood barriers are available in different sizes and lengths and are reusable. They deflate when they dry and reactivate when they get wet again to absorb water and swell to create a barrier. This type of flood barrier can be placed in position when flat and dry. However, a flash flood could carry the deflated bags away. The manufacturer may suggest pre-soaking and stacking them to keep them in place.
This type of flood bag doesn’t work with salt water or chlorine.