Wrapping a building with plastic and allowing floodwater to contact the building is suited only to homes without basements and to areas with clay soils, under circumstances where floods are only hours in duration and where flood levels are below 2 feet. Properly constructed walls in good condition should be able to withstand the pressure of a couple feet of water for a few hours. All openings, such as windows or doors, will require a flood closure over the opening. Flowing water creates a tremendous force; this can damage the structure. Houses can be displaced from their foundations and basement walls pushed in by floodwaters and saturated soil. Check with local emergency management officials, engineers, or building inspectors before allowing water against a building.

Depending on the duration of flooding and the ease with which water flows through the soil, a buoyant (upward) force may occur in areas behind a dike that are not covered with floodwater. Watch for water boils, water coming up through the soil, or movement of floors within protected areas. Sometimes it is necessary to flood protected areas with clean water to prevent floodwater from entering.