500 LAUREL DR 2016-01-01 MF Import

Geotechnical Engineering Study 00-2267 Three Stary Addition - 500 Laurel Street, Everett January 31, 2001 z Page 23 " 1 As indicated, we also recommend the upper on� foot of passive pressure be neg- lecied in design unless the suil is overlain with either a�oor slab or paving. Slab-on-Grade Floor A concrete sl�b-on-grade floor supported on either the existing firm, undisturbed or redensified in-place silty sand or sandy silt soil, or on a new compacted structural fil! pad placed over the firm underlying material, is appropriate for all or part of this structure. Any soft, loose or distufi�d soils should be carefully recompacted before constructing the slab. We recommend that the foilowing parameter be used in floor slah design: ■ Vertical modulus of subgrade reaction for = 325 pci concrete floor slab on redensified native soil subgrade ■ Vertical modulus of subgrade reaction = 275 pci for a concrete floor slab on a pad of compacted fill over the redensified native soil subgrade Because of the potentia! for underslab seepage, we recommend a capillary break be included beneath the slab to provide space for vapor transmissior.. This capillary break should consist of at least four inches of clean, free-drai�ing granular material, such as coarse sand or pea gravel. In araas wr�ere moisture vapor transmission through the slab is undesirable, we recommend an impermeable vapor barrier be instailed over the capillary break beneath the slab. A 6 mil plastic membrane is typically e�equate for this purpose. This membrane will help preve:nt moisture vapor transmissiori up through the slab and the associated moisture-rela±ed damage to interior �umishings and salt generation in the surface of concrete slabs. C�