Most flood-proofing advice centres on keeping the water out. But if your property is at risk of severe overland flooding, it turns out that might not be the best strategy. If you make your basement into a watertight “underground boat,” the hydrostatic pressure of the water pushing against the walls can damage your foundation and ruin the structural integrity of your cottage. The walls will literally buckle and collapse.
Today, more and more home- and cottage owners with basements in flood-risk areas are taking a “wet floodproofing” approach. That means letting water in on purpose, but using materials and designs that won’t be damaged, such as metal and polished concrete, plastic lumber, glazed clay tile, marine grade plywood, ceramic or concrete tile, steel wall panels, metal doors, and plastic foam insulation. This approach restricts how you’ll use the space, though. It won’t be as cozy as a typical renovated basement.