Protect Your Basement From Flood Damage
Take your time when pumping out your basement after a flood.
“No matter the type of basement wall construction, if the basement is flooded with more than 6 inches of water, you could cause more damage by pumping the water out too soon than by letting it remain,” warns North Dakota State University agricultural engineer Tom Scherer.
If you pump the water out too quickly, the floor may push up and walls cave in. Water in the basement helps brace the walls against the pressure of water-logged soils outside the home. Also, don’t pump water out until the floodwaters around your house recede.
When you’re ready to pump your basement, don’t use an electric pump powered by your electrical system, says NDSU agricultural engineer Ken Hellevang. Instead, use a gas-powered pump or an electric-powered pump connected to an outside line.
He recommends removing about 2 to 3 feet of water, then watching for signs of structural failure before pumping out more water. Scherer says that if you don’t find problems, then pump about a third of the water each day, making sure you pump it well away from the house.
“Don’t rush the pumping because the soil may be very slow to drain,” Hellevang says. “Whatever is submerged in the basement will not be damaged further by delaying the pumping.”
If water is leaking into your basement but your sump pump can keep up with it, you may want to brace or shore up the walls if they are cracked, out of plump or bulging, Scherer says. Unbraced block-construction walls are especially vulnerable.
Use long poles 6 inches or more in diameter to hold walls apart horizontally. A screw jack between one wall and the end of a pole can put equal pressure on both walls.
Several braces may be necessary, depending on the length and condition of the walls. Scherer suggests using one brace about every 10 feet of wall length about 4 feet up the wall from the floor. Also use a continuous piece of timber or other material between the poles and wall to prevent the poles from puncturing the wall.