3121 8TH ST AB 2016-01-01 MF Import

June 1,200b Duplex Building L&A Job No. fiA055 Page 13 SLA}3-ON-Gf2ADE FLOORS Slab-on-grade floors, iCused, should be placcd on fimi subgrade soils prepared as oatlined in thc SI7'G PIt�PARATION AND GLNHRAL EARTFfWORK and the STRUCTURAL F[LL sections of this report. Wher� moisture control is critical, the slab-on-grade lloors should be placed on a capillary break which 'ss in turn placed on the r.�mpacted subgrade. Thc capillary break should wnsist of a minimum four-inch-thick layer of Gce-draining gravel or crushed rock containing no more than 5% by weight passing ihc No. 4 sieve. Wc recommend that a vapor barrier, such as a 6-mil piastic membrane, bc placed over the capillary break to kecp moisture Gom migrating upwards. DRNG�i�AY 1'AVGMI'sNT Duc lo the steep slope flanking thc site on the east side, wc recommend that the paved driveway not be located on the east side of the duplex building. It is our opinion that the dri� eway on the west sidc of thc building as shown on ti�c desicn plans is appropriatc. Pcrlarmancc of driveway pnvcmrnt is critically relatcd to thc conditions oP the underlying subgrade soils. We recommend that the subgrade soils within the driveway be treated and prep�red as described in the SIT'L PREPARA7'ION AND GL'N6RAL GARTI-IWORK section of this report. Yrior to placing base material, Uie subgrade soils should be compacted to a non- yiclding state with a vibratory roller compactor, and proof-rolled with a piece of heavy construction cquipment, such as a fully-loade� dump truck. Any are:is with excessive tlexing o� pumping should be overeacnvated and re-compacted or replaced with a structural fill or crushed rock placed and compactcd in accordance with the recommendations provided in the S'l'RUC7'URAL PILL section of this report. LIU & ASSOCIAT�S, INC.