How To Build A Sandbag Dam

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If you live near water and expect a flood, make a sandbag dam to protect your property. Sandbags may not stop the flooding completely, but they lessen the risk of costly repairs. 

Sandbags are commonly available at landscape supply stores or hardware stores, however;  they may get in short supply at the anticipation of a flood, so it's ideal to start building the dam as soon as possible. Here are tips to build a sandbag dam.

Prepare to Build the Dam

To build the dam, you need:

Determine the best locations for the bags. You want to make a straight path about eight foot from the walls between the end points of the dam, where the dam and shore meet. The extra space gives you room to make the dam bigger if needed. Avoid placing bags against walls, unless the wall can tolerate floodwater.

Fill the Sandbags

Sandbags can weigh up to forty pounds, so enlist an assistant to help you carry and fill them. Use the shovel to fill the bag two-thirds to one-half of the way full, while the assistant holds it open. Flatten the empty portion of the bag. Don't tie the bag, unless you plan to transport the bags.

Place the Bags

Lay the bags in groups of two on the water source; touching the seams together. Consider the seam of the bags like the spine of an open book. 

Lay the bags on the creek bed in a brick pattern. or if water is present, guide the bags into the water. Use the shovel to flatten the bags to provide a stronger structure.  

Lay the second course, covering the empty part of the bags on the first course and tucking the flaps on the end bags. Place three or four more courses.

Build the Wood Wall

Measure the height of the sandbag dam, and mark it on lumber. Cut the lumber to fit with the saw, and drill pilot holes for the bolts. 

Set the wood every three feet on the base at an angle, then hammer them into the ground with the sledgehammer. The wood wall should look like a lean-to frame. Fasten the boards together with the bolts, and use the wrench to tighten them. Secure the board ends to stakes made from the lumber or trees.

Don't forget to cover indoor drains, vents, toilet bowls, and doorways to prevent back-flow. Never ignore warnings to evacuate the area. If you need more assistance, contact a flood prevention service. Companies like John's Waterproofing can help.