1228 GRAND AVE Geotech Report 2022-10-25

April 7,2008 Mr.Don Levin L&A Job No. 8A037 Page 13 walls equal to the wall height. A 4-inch perforated PVC footing drain pipe, as recommended in the DRAINAGE CONTROL section of this report, should be provided for the basement or extended footing walls. The footing drain lines should be hydraulically connected to the drainage blanket behind the walls. SLAB-ON-GRADE FLOORS Slab-on-grade floors, if used, should be placed on firm subgrade soils prepared as outlined in the Site Preparation and General Grading and the Structural Fill sections of this report. Where moisture control is critical,the slab-on-grade floors should be poured on a capillary break which is in turn placed on the compacted subgrade soils. The capillary break should consist of a minimum four-inch-thick layer of free-draining gravel or crushed rock containing no more than 5% by weight passing the No. 4 sieve. We recommend that a vapor barrier, such as a 6-mil plastic membrane,be placed over the capillary break to keep moisture from migrating upwards. DRIVEWAY PAVEMENT Performance of driveway pavement is critically related to the conditions of the underlying subgrade soils. We recommend that the subgrade soils under the roadway be treated and prepared as described in the Site Preparation and General Grading section of this report. Prior to placing the base material, the subgrade soils, after stripping of surficial unsuitable soils, should be compacted to a non-yielding state with a mechanical compactor and proof-rolled with a piece of heavy construction equipment, such as a fully-loaded dump truck. Any areas with excessive flexing or pumping should be over-excavated and re-compacted or replaced with a structural fill or crushed rock placed and compacted in accordance with the recommendations provided in the Structural Fill section of this report. LIU & ASSOCIATES, INC.