5109 SOUND AVE 2017-08-02 - Laserfiche WebLink

July 21, 2014 Two Single-Family residences L&A Job No. 14-065 Page 20 Building Footing Drains A subdrain should be installed, around the perimeter footings of each proposed building. The subdrains should consist of a 4-inch-minimum-diameter, perforated, rigid, drain pipe, laid a few inches below bottom of the perimeter footings of the buildings. The trenches and the drain lines should havc a suff cient gradient (0.5% minimum) to generate flo��v by b avit��. The drain lines should be wrapped in a non-woven filter fabric sock and completely enclosed in clean washed gravel. The remaining trenches may be baekfilled with clean onsite soils. Water collected by the perimeter footing subdrain systems should be tightlined, separately from the roof and surface stormwater drain lines, to discharge into a storm sewer or suitable stonnwater disposal facilities. Surface Drainage Water should not be allowed to stand in any axeas where footings, on-grade s1aUs, or pavement is to be constructed. Finish ground surface should be graded to direct surface runoff away troin proposed buildings. We recommend the finish ground be sloped at a gradient of 3 percent minimum for a distance of at least 10 feet away from the buildings, except in the areas to be paved. Cleanouts Sufficient number of cleanouts at strategic locations should be provided for underground drain lines. The underground drain lines should be cleaned and maintained periodically� to prevent clogging. LIU & ASSOCIATES, INC.