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April 7, 2008 <br /> Mr. Don Lcvin <br /> L&A Job No. 8A037 <br /> Pagc 15 <br /> Building Footing Drains <br /> A subdrain should bc installcd around thc perimctcr footings of thc new residcncc to minimirc <br /> accunuilation of groimdwatcr undcr thc building. Thc subdrains should consist of a 4-inch- <br /> minimwn-diamctcr, perforated, rigid, drain pipc, laid a few inchcs bci w thc bottom of perimctcr <br /> footings. Thc trcnches and thc drain lincs should have a sufficicnt gradicnt (0.5 percent <br /> minimum) to gcncratc (low by gravity. Thc drain lincs should bc cnclosed in washcd gravcl and <br /> complctcly ���rappcd in non-wovcn filtcr f:�bric lo within about 12 inchcs of finish gradc. Thc <br /> rcmaining Ircnchcs may bc backfillcd �viQi on-sitc impervious soils. Watcr collectcd by thc <br /> footing drain systcros should bc tightlincd, scparatcly from Uic roof and surfacc stonnwatcr drain <br /> systcros, to dischargc into a nc:irby stomi sc�vcr. <br /> 5urfacc Draina�;c <br /> Watcr should not bc allo���ed to sta�id in any .u'cas whcrc footings. slabs, or pa��cmcnt is to bc <br /> constructcd. Pinish ground surfacc shoulcl bc gradcd to flow away from thc nc��� residcncc. \1'c <br /> ���o,,,�„��,� a,� r�,�5t, �ra���,�i �� sion�d at a gradicnt of 3 perccnt minimum for a distancc of at <br /> Icast 10 Icct away I�rom thc huildings, cxccpt in thc arcas to bc paval. <br /> Clcanouts <br /> Suflicicnt numbcr of cicanouls at stratcgic locations should bc pro��idcd for thc undcrground <br /> drain linc systcros. 'fhc undcrground drain linc s��tcros should bc maintaincd periodically to <br /> prcvcnt clocging. <br /> RISI� F.�'�U.UA'f10N S'1'A'I'E�1F.N"1' <br /> Thc sitc is undcrlain at shallo��� depth by dcnsc silty sand .md hard finc sandy silt soils. 1'hesc <br /> soils :ur ol' high shcar su�englli in thcir nativc undisturbed statc anJ havc cxccllent resistvicc <br /> '� <br /> LIU & ASSOCIATES, INC. ' ,� �� <br /> f►�� � ,� <br />