Measure the door width and add 2-3 inches on each side for optimal protection against fast-moving water.
Extending the dam beyond the door lets it gain extra support from the exterior wall, strengthening its resistance to water pressure.
For height, consider previous flood levels and build the dam slightly higher to ensure adequate protection.
Use a 2-inch side extension for dams under 4 feet wide, and a 3-inch extension for wider dams.
In high-risk flood areas, a 4-foot-tall dam attached to the exterior wall offers maximum stability. If the exterior wall can’t reinforce the dam, the door frame can serve as an alternative for bracing.
Address any wall or door frame indentations that may prevent a tight seal by using the door frame to improve the fit and prevent seepage.
