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� � � � C <br /> ' Harris-Ts�ng Architects E.4212 <br /> December 30, 1988 Paee S <br /> � I <br /> ` • Minimum width of wall footings = 18 inches I <br /> • Minimum lateral dimension of = 24 inches <br /> ( rnlumn footings I <br /> . � <br /> • Estimated total post- = 1 inch, or less i <br /> ` construction settlement <br /> � • Fstimated post-rnnsuuction = 1/2 inch <br /> differential settlement; <br /> across building width <br /> ( A one-third increase in the above allowable bearing pressures can be used when considering <br /> short-term transitory wind or seismic loads. <br /> Slab-on-Grade Fioors <br /> Slabs can be placed on structural fill cr natural soil, after the subgrade is stripped and <br /> proofrolled. F7oor s?abs should be "free floating", so that any possible future differential <br /> settlement betueen t]oor slabs, columns or walls will not be reflected in the form of warped <br /> or cracked floor slabs. <br /> Floor slabs should be properly water-proofed and moisture-proofed, and should be provided <br /> with a capillary break rnnsisting of a minimum of four inches of free-draining sand and <br /> gravel. �'e also recommend that a vapor bamer, such as a 6-mil plastic membrane, be <br /> � placed over the capillary break beneath the slab to reduce both water vapor transmission <br /> through the slab and the resultant moisture related damage to interior fumishings. <br /> Two to four inches of moist sand may be placed over the membrane for protection during <br /> construction, to aid in curing of the concrete, and to help prevent cement paste bleeding <br /> down into the underlying capiliary break through joints or tears in the vapor barrier. <br /> Site Drainaee <br /> The site should be graded such that surface water is directed off the building area. Water <br /> should not be ailowed to stand in any area where buildings, slabs or pavements are to be <br /> constructed. <br /> During construction, loose surfaces can be sealed at night by compacting the surface to <br /> reduce the potential for moisture infiltration into the soils. Final site grades should allow <br /> for drainage away from the building foundations. We suggest that the ground be sloped at <br /> a gradient of 3 percent for a distance of at least ten feet away from the buildings except in <br /> areas that are to be paved. <br /> Earth Consultants, Inc. <br /> I <br />