4808 BELVEDERE AVE 2016-01-01 MF Import

Timberbuild Homes September 20, 2005 DRAINAGE CONSIDERATIONS JN 05357 Page 11 Foundation drains shouid be used where (1) crawl spaces or basements will be below a structure, (2) a slab is below lhe outside grede, or (3) the outside grade does not slope downward from a building. Drains should also be placed at the base of all earth-retaining walis. These drains should be surrounded by at least 6 inches of 1-inch-minus, washed rock and then wrapped in non-woven, geotextile filter fabric (Mirafi 140N, Supac 4NP, or similar matenal). At its highest point, a perforated pipe invert should be at least 6 inches below the bottom of a slab floor or the level of a crawl space, and it should be sloped for drainage. All roof and surface water drains must be kept separate from the foundation drain system. A typical drain detail is attached to this report as Plate 4. For the best long-term performance, per�^�ated PVC pipe is recommended for all subsurface drains. As a minimum, a vaFor retarder, as defined in the S/abs•On-Grade sedion, should be provided in any crawl space area to limit the transmission of water vapor from the underfying soils. Also, an outlet drain is recommended for all crawl spaces to prevent a build �p of any water that may bypass the footing drains. No groundwater was observed during our field work. However, if seepage is encountered in an excavation, it should be drained from the site by directing it throuyh drainage ditches, perforated pipe, or French drains, or by pumping it from sumps in!erconnected by shaliow connector trenches at the bottom of the excavation. The excavation and site should be graded so that suAace water is di�ected off the site and away from the tops of slopes. Water should not be allawed to stand in any area where foundations, slabs, or pavements are to be constructed. Final site grading in areas adjacent to the residence should slope away at least 2 percent, excepf where the area is paved. Surface drains should be provided where necessary to prevent ponding of water behind foundation or retaining walls. Ad�ilionally, a drainage swale should be provided on the upslope sides of the residence to intercept surface run-off and direct it into the storm drains. Water from roof, storm water, and toundation drains should not be discharged onto slopes; i! should be tightlined to a suitable ouNall located away from any slopes. GENERAL EARTHWORK AND �T02UCTURAL FILL All building and pa•dement areas should be stripped of surface vegetation, topsoil, organic soil, and other d�leterious material. The stripped or removed materials should not be mixed with any materials to be used as structural fill, but they could be used in non-structural areas, such as landscape beds. Structural fill is def�ned as any fill, including utility backfill, placed under, or close to, a building, behind permanent retaining or foundation walls, or in other areas where the underlying soil needs to support loads. All structural fill should be placed in harizontal lifts with a moisture content at, or near, the optimum moisture content. The optimum moisture content is that moisture content that results in the greatest compacted dry density. The moisture content of fill is very important and must be closely controlled during the filling and compaction process The allowable thickness of the fiil �ift will depend on the material type selected, the compaction equipment used, and the number of passes made to compact the lik. The loose lift thickness should not exceed 12 inches. We recommend testing the fill as it is placed. If the fill is not Gf_OTECH CONSULTANTS,INC.