How to Use Sandbags to Protect Property Against Flooding

One of the largest dangers of tropical storms, hurricanes, and cyclones is the flooding they cause along coastlines. Millions of dollars of damage is caused by flooding each year. Learning how to use sandbags to protect your property against flooding can save you money, hassle, and time.

Obtaining The Sandbags

There are a few options available when looking for suitable sandbags. One is to simply use untreated burlap bags, generally used for animal feed, rice, or grains. You may be able to purchase these at your local hardware or farm supply store or you can find several sources online. Another option is the new synthesized woven plastic bags, made especially for sandbagging. These have the benefit of lasting longer if cared for properly. Again, there are several good sources of this type of sandbag online. Although garbage bags seem like a good choice for sandbags, their exterior makes them too difficult to handle and too slippery to stack properly.

Filling The Sandbags

Once the danger of flooding has presented itself, it's time to fill the sandbags. Note that they should not be filled and stockpiled for future use as the soil or sand that fills them will degrade the bags quickly.

It takes two people to effectively fill the sandbags. The material you use can be soil, sand, or small gravel (only if no other materials are available). Fine sand may sift through natural burlap bags so is best used in the plastic ones. One person will kneel down near the pile of fill and hold the bag open and stable. The other person will shovel the fill material into the sandbags until they are about half full. For temporary sandbag placement, the sandbags should not be tied off but the open flap should be flattened and folded underneath the full bag. The bags could weigh anywhere from 25 to 35 pounds when full so proper attention should be paid so as to avoid injury.

Placing The Sandbags

Once the sandbags are full, they can be stacked where needed. The ground underneath where the sandbags will be placed should be flat and clear of debris such as twigs and leaves. Before final placement of the sandbags, determine from which direction the water will come and where you want to divert it to. Water building up on the other side of the sandbag wall will need to flow somewhere else so make sure you know where you want it to go. For example, diverting flood water from your property and directing it at the neighbor's property is not a good idea for many reasons, including the fact that it could open you up to lawsuits.

Once the nature of the diversion has been established, you can start building the sandbag wall. The sandbags will act much like bricks and are placed in a similar fashion. The first row is laid with the sandbags nestled tight up against each other. The second row is laid with each bag being offset a half-bag's width from the first row. The third row goes on top offset against the second row of sandbags. After laying each row, push down on each sandbag to ensure that it provides the best water block and nestles into the adjacent sandbags. For sandbag walls in excess of three feet, it will be necessary to double the wall and use two rows of sandbags for each course. Otherwise, the pressure from the rising water could topple the entire structure.

After The Threat

When the threat of flooding has passed, dismantle the sandbag wall and empty the bags of their material as quickly as possible. Soil or sand left in sandbags can cause the bags to break down quickly. After each sandbag has been dumped, let dry in the sun until there is absolutely no moisture left in the bags, then store in a cool dry place until the sandbags are needed next time.