1725 GRAND AVE 2018-01-02 MF Import

(- � � I November 10, 2000 G-1266 Gillette Residence Pa6�8 To prevent buildup of hydrostatic preasure behind pertnanent concrete basement nr conventionai I rotaining walls, a granular, frce draining structural backfill material should be plsad within a horizontal distence of 18 inches ofthe well, in place of vertical drain mats. We recommend using I a clean, granular, free-draining, structural fill material. The free-draining granular material ahould i also surround the foundation footing drain. The top 12 inches of the fill should consist of campacted and relatively impermeable soil. This cap material can be separated from the undedying more granular drainage material by a geotextile fabric. Alternatively, the surface can � be sealed with asphait or wncrete paving. The surface should be slopeci to drain away&om the I building wall. �; I Bsckfill material behind pemianent concrete retaining walls should be compacted to 90 percent of the maximum dry density determined by ASTM D 1557-91 (Modified Proctor Method) as specified in Sation 5.3: Structural Fill. The backfill in areas adjacent to concrete reteining walls should be compacted with hand held equipment or a hoe-pack. Heavy compacting machines should not be allowed within a horizonta( distance to the wall equivalent to one half the wal! height, unless the walls are designed with the added surcharge. S.S Drain�ge Conaider�tiona We recommend that drains be installed around the per.meter of the foundation footings and behind the base of retaining or basement walls. The drains should consist of a four inch minimum diameter, pedorated, rigid drain pipe laid st or near the bottom af the footiug with a gradient sufficient to generate flow, as schematically illustrated in Plate 3 - Typical Besement Wal!Backfill and Drainage Detail. The drain line should be bedded on, suRounded by, and covered with a frce- draining rock, peu gravel, or other free-draining granular material. The drain rock should be wrapped in a layer of geotextile fabric. Once the drains are i�stalled, the excavation should be � backfilled with a compacted structural fill material. The surface can be sealed with asphalt or concrete paving. � Under no circumstances should roof downspout drain lines be connectcd to the footing drainage system. Alt roof downspouts must be separately tight lincd to an appropriate stortn water Geo Group Northwe�t, Inc. �/��{ +i��.;i.-`.