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<br />Many qualified house-moving contractors know the techniques for elevating a building. The <br />structure is jacked up and temporarily set on cribbing while a new foundation is built <br />underneath. The foundation walls are raised to the flood protection level and the house is <br />lowered onto the new foundation. Utility lines are extended and reconnected. steps are built <br />and. in some cases, the perimeter is backfilled or landscaped to mask the change. <br /> <br />The walls of the new foundation must have openings to allow floodwaters to pass under the <br />building. Otherwise, hydrostatic pressure will be placed on the walls and floor, and the <br />foundation would be in danger of cracking or breaking. In areas subject to wave action or <br />higher velocity flooding, elevation on columns or pilings is recommended to minimize the <br />exposure to these hazards. <br /> <br />Figure 1. House Elevated over Garage <br /> <br /> <br />~ <br />n!U <br />~ <br /> <br />When raised 8 feet or <br />more. a new story <br />is created <br /> <br />Utilities and electrical <br />circuits moved above <br />f700d level <br /> <br />Light'.Vei~ht or mobile items <br />can be stored under the house <br />and moved after the flood <br />warning <br /> <br /> <br />,;============;-, <br />" 'I <br />" \, <br />, " <br />6.?~;;~;~~~;';-Z~~.; <br />,\_I~Il"Q""",,:'_I_" <br />~'::-~::j:~: <br /> <br /> <br />, r~. <br />Openings on each wall <br />ensure entry ofwarer <br />to prevent hydrostatic load <br /> <br />l. ~' <br /> <br />If the flood protection level is low, the result can be similar to building a house over a 2- or <br />3-foot crawlspace. If the house is raised 2 feet, the front door would be 3 steps higher than <br />before. Examples of such low elevation projects are shown in Figure 12 on page 26. If the <br />house is raised 8 feet, the lower area can be wet flood proofed for use as a garage, to provide <br />access to the building, or for storage of items not subject to flood damage (see Fig\lre I.). <br /> <br />Cost: $8.000 to $50,000. depending primarily on the type of building. <br /> <br />2.2 Barriers <br /> <br />Barriers keep floodwaters from reaching a building. They can be made of earth, concrete, <br />masonry or steel. Large earth barriers are called levees. In shallow flooding areas. a <br />common approach is to construct a berm. which is a small levee, usually built from locally <br />available fill. <br /> <br />Sheer mass gives berms and levees their strength. A typical design has 3 horizo!Ulll feet for <br />each vertical foot (3: I slope), so at least 6 feet of ground is needed for each foot in height. <br />Thus, berms and levees need a lot of room (see Figures 2 and 10 on pages 4 and 24). <br /> <br />-3- <br />