2001 Geotechnical Evaluation Report

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RVC Homes Project BABX-01-0124 April 12, 2001 Page 10 As a precaution against basement seepage,we recommend installing a perimeter foundation drain system. The system should include a perforated pipe with an invert within 2 inches of bottom-of- footing elevation. Collected seepage should be routed to a sump and then drained by a pump or gravity to a storm sewer or low area on the site. The seepage control system should include permeable material against the basement wall, such as a synthetic wall drainage system or at least 2 feet(horizontal)of permeable sandy gravel or sand backfill. The sandy gravel or sand backfill should have less than 5 percent of the particles by weight passing a number 200 sieve. Where the sandy gravel or sand backfill extends outside the footprint of the building, it should be capped by a slab, pavement or 1 foot of clayey topsoil. D.5.c. Earth Pressure. Backfill against the basement wall should be compacted to a minimum of 90 percent of its standard Proctor maximum dry density. Beneath steps, slabs and pavements, it should be compacted to a minimum of 95 percent. The walls should be braced prior to backfilling. If imported sandy gravel or sand is used as backfill against the wall, a lateral earth pressure of 40 psf per foot of depth should be used to design the basement wall. If clayey soil is used as backfill against a synthetic wall drainage system, we recommend using a lateral earth pressure of 60 psf per foot of depth for designing the wall. We do not recommend clayey soils be used for wall backfill. D.6. Settlement Plate Monitoring We recommend two to three settlement plates be surveyed and periodically monitored to document settlement of areas where grade changes in excess of two feet will occur. We recommend the settlement data be reviewed by a geotechnical engineer and risk assessments of future settlement be made prior to completion of exterior features. D.7. Cold Weather If soil correction work and construction is anticipated during cold weather, we recommend that good winter construction practices be observed. All snow and ice should be removed from cut and fill areas prior to additional grading. No fill should be placed on soils that have frozen or contain frozen material. No frozen soils should be used as fill. Concrete delivered to the site should meet the temperature requirements of ASTM C 94. Concrete should not be placed upon frozen soils or soils which contain frozen material. Concrete should be protected from freezing until the necessary strength is attained. Frost should not be permitted to