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<br />Some precautions: <br /> <br />Some houses already have subsurface drainage placed under the floor <br />to relieve a basement floor from the uplift pressures of a high <br />water table. This location is not very effective for draining <br />water on the other side of the footing. <br /> <br />~ubsurface drainage depends on a pump to work. Pumps that use <br />nouse current may stop running if electricity is lost during a <br />storm. Back up systems are available that use batteries or <br />gasoline. <br /> <br />Subsurface drainage cannot be expected to handle surface flood <br />waters that come down the crack between the ground and your wall. <br />That would be like trying to drain the river with one pump. <br /> <br />)n most communities it is illegal to connect a sump pump to the <br />sanitary sewer. Water is normally pumped out onto the ground, <br />above the flood height. <br /> <br />An alternative to outside tiles is internal drainage or "stone <br />ti1 ing" under your floor. Water seeping through cracks or <br />deliberately drilled holes can be guided along floor drains to <br />the sump. Internal drainage is a good precaution to take even <br />with outside tiles. <br /> <br />Uplift: When the ground under the house gets saturated, the water will <br />push upward seeking its own level. Uplift forces place the house in <br />danger in two ways: <br /> <br />1. The floor could crack or break just as a wall will from <br />lateral pressure. <br /> <br />2. The entire house could be lifted up and, in effect, float. <br /> <br />Again, a structural engineer needs to be consulted. However, here are <br />some general guidelines: <br /> <br />A one or two story wood frame house, without basement (even with <br />partial brick or masonry siding), may float if the flood waters <br />reach three feet above the first floor. <br /> <br />If three feet of flooding does not float a one or two story house <br />on a slab, it will probably cause the slab to buckle. <br /> <br />.' <br />~ basement floor will probably fail when the ground is saturated <br />up to four feet above the floor. <br /> <br />Uplift depends on water getting under the house. To protect against <br />this, the ground underneath a slab or basement floor needs to be drained. <br />Subsurface drainage, discussed above, is the best protection. Subsur- <br />face drainage will not help a house on a crawl space. A structural <br /> <br />14 <br />