How do I use sandbags?

Sandbags alone should not be relied on to keep water outside a building. Use baffle boards (plywood sheeting) or sheets of plastic tarp with sandbags. To form a sandbag wall, place bags tightly against one another to form the first layer of defense. Stagger the second and subsequent layers of bags, much like the pattern of bricks in a wall.

Sandbags should never be used to build a fortress around the perimeter of one's property. Doing so can actually trap floodwaters between sandbag walls and structures, leading to further damage.

 
Building a last line of defense around your home

Steps to protect your home

How to make baffle boards to temporarily seal foundation vents, windows, doorways and garage doorways:

These steps should only be taken immediately prior to flooding and removed immediately after the threat of flooding has passed.

• Use 3/4" plywood to overlap the window or vent by three or four inches on all sides.
• Use a soft gasket material like felt or foam rubber that is at least 2 inches wide. Attach it with waterproof glue to the 3/4" plywood.
• Use four or more nails, screws or bolts to secure the baffle boards over the opening. In stucco, cement or brick walls, special screws or expansion bolts will be required.
• For doorways, install baffle boards to the outside frame of the door.
• For garage doors, suitable boards one-inch thick may be used instead of plywood for the door seals. The bottom edge of the baffle board should be shaped to fit the driveway surface so there will be a watertight seal on the bottom. Use baffles to seal door cracks vertical to and higher than the bottom seal.
• In an emergency, fasten sheets of plastic or building (tar) paper over the opening and seal with caulk, putty or clay.
• Baffle boards (above), consist of 3/4 inch plywood sheets with a soft gasket material like felt or foam rubber. They are effective for closing off vents, low windows and doors from floodwater. If placed over vents, however, baffle boards must be removed once the danger of flooding passes.
• Using plastic tarp between a structure and sandbags helps keep floodwater from seeping between the house siding and foundation sills.
• Care should be taken to place sandbags tightly against one another. Place the next sandbag over the folded, tied end to provide a good seal. Complete each layer before starting the next layer. Limit placement to two layers.
• After placing the first layer of sandbags, stagger the second layer of bags, much like the pattern of bricks in a wall.

Taking these precautions will minimize the amount of water and sediment entering your home and crawl space and prevent damage to your home’s structure.