25 10 28 Slope Stability Review

Chairman and Members of the West Orange Planning Board Application No. PB24-01, West Essex Highlands, LLC, Warner Road, Block 179, Lot 32 Review of Applicant’s Engineer’s Slope Stability Analysis Reports, the Objector’s Engineer’s Response Reports; and the Applicant’s Engineer’s Rebuttal Report October 28, 2025 Page 5 of 21 The elevation of rock at Boring LB-3 was reported at elevation 605 which is approximately 23 feet above the level of the entrance to the parking level at the south building wall. The grading of the garage floor levels below the building is not indicated on the reference drawings. We have considered that the floor will be approximately level for the purpose of this evaluation. 3. Building Height and Loading as Considered for the Slope Stability Evaluation: The Architectural and Site Plans divide the building into two parts separated at the main entrance. The part to the north of the entrance is designated as Building D.1 and the segment to the south is designated as Building D.2. Review of the Architectural elevation details indicates that Building D.1 includes 5 floor levels from the garage to the 4 th Residential Floor. Review of the architectural elevations indicate that the southern section of the building will include 2 garage floor levels at elevations at 582 and 594, respectively, and that there will be 4 residential levels. In addition, there will be a roof-top assembly area. We anticipate that code-required floor live loads will range from 40 to 100 pounds per square foot. Langan has assigned an average area footprint load of 1,000 psf for Building D. The assumed loading is equivalent to an average combined dead and live loading of 144 psf for Section D.2 and 166 psf for Building D.1. Structural drawings indicating the building floor details, and construction type were not available to check the likely distributed dead loading. The assumed loading is not, in our opinion, an upperbound assumption, and assumes a relatively low average area dead load for the structure. The load distribution indicated in the Langan report indicates that the building influence on the slope is likely not to be a determinant in the stability of the slope. The evaluation did not include an evaluation of the benefits of “weight credit” achieved by removal of the existing soils in the basement, or directly consider the maximum past pressure that

he slope. The evaluation did not include an evaluation of the benefits of “weight credit” achieved by removal of the existing soils in the basement, or directly consider the maximum past pressure that was imposed on the glacial soil deposits and underlying rock by prior glacial activity. Proposed Yard Grading Along Ridge Line Our review indicates that the building location shown on the Stability Investigation drawings conforms to the layout shown on the Preliminary & Final Site Plan drawings. The rear wall line of the building measures approximately 10 to 40 feet from the line on the reference drawing connecting the high points on the ridge. We have marked out a line representing the line at which the slope steepens to more than 15 degrees downward to the east and northeast. The line is shown on the markup and ranges from approximately 40 feet at the northeast corner of Building D.1 to 140 feet at a point opposite the main entrance to the building.