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Hana Japan Steak House 5150.100.001 11991 Dublin Canyon Road November 11, 2024 RESPONSE TO COMMENTS Page 7 ENGEO Response to Comment 22 Passive resistance exists as long as the soil continues to exist. It is highly unlikely that a foot of erosion could occur on this site adjacent to a footing. As such, we will leave this portion of the report as is. Comment 23 Geotechnical Report, Section 8.1 (Exterior Flatwork): Consideration should be given to recommending placement of a layer of low expansion potential soil having a plasticity index of less than 12 under the exterior flatwork (such layers are typically 6+ inches thick). Previous sections of the Geotechnical Report recommend removing clay soil (expansive soil) from under building pads, but do not mention exterior flatwork. Consideration should also be given to recommending that thickened edges extend at least 2 inches below the low expansion potential soils where adjacent to landscaping in order to reduce the potential for migration of landscaping water into the subgrade for exterior flatwork. ENGEO Response to Comment 23 These considerations are more stringent than the City of Pleasanton standard details for sidewalks. We will defer to the owner if they wish to implement these considerations for their private development; however, we opine that our recommendation of a 5-inch concrete section with No.3 reinforcing bars at 18-inch centers, each way, is at least similarly robust as the City’s 4-inch concrete section on a 3-inch-thick aggregate base section, and is appropriate for the moderately expansive clay encountered in our explorations. As such, we will leave this portion of the report as is. Comment 24 Geotechnical Report, Section Slab 8.2.2 (Slab Moisture Vapor Reduction): a. Consideration should be given to specifying the minimum thickness of the vapor retarder membrane. Using a membrane with a minimum thickness of 15 mil is considered current industry standard. b. Consideration should be given to eliminating the last paragraph of this section of the Geotechnical Report. Placing a layer of sand or gravel over the vapor retarder membrane is no longer considered industry standard as it could result in the entrapment of water between the vapor retarder membrane and the slab leading to long-term vapor moisture issues. ENGEO Response to Comment 24 a. We respectfully disagree; the reviewer is not correct about the current industry standards. We recommend conformance with an ASTM standard that identifies minimum strength and permeability. These properties can be achieved with different thicknesses of vapor retarder depending on the material it is made of; for instance, Stego makes a 10-mil vapor retarder out of virgin polyolefin that conforms to ASTM E1745 Class A. Alternatively, a 15-mil-thick vapor retarder can have lesser performance if made of recycled materials. b. We are not recommending the placement of a sand layer; we are deferring to the structural engineer if they wish to. How the slab is cured is not a geotechnical engineering item, and as such, we will leave this portion of the report as is. Comment 25 Geotechnical Report, Section 10.1 (Flexible Pavements): This section of the Geotechnical Report recommends that the upper 18 inches below finished subgrade within flexible pavement areas of the Site have an R-Value of at least 25. Caltrans typically requires that the upper 24 inches of the pavement subgrade meet a specific R-Value. Therefore, consideration should be given to increasing the depth of the pavement subgrade associated with the minimum recommended R-Value to 24 inches.