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HomeMy WebLinkAboutObservation of Excavation 04.18.2024Kumar & Associates, Inc. 0 K Geotechnical and Materials Engineers 5020 County Road 154 and Environmental Scientists Glenwood Springs, CO 81601 phone: (970) 945-7988 fax: (970) 945-8454 email: kaglenwood@kumarusa.com An Employee Owned Company www.kumarusa.com Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado April 18, 2024 Maley Building Corp. Attn: Jason Brown P.O. Box 4028 Basalt, Colorado 81621 j ason(a)maleybuilding. com Project No. 23-7-274.A Subject: Observation of Excavation, Proposed Residence, Lot 7, St. Finnbar Ranch, 30 St. Finnbar Road, Garfield County, Colorado Dear Jason: As requested, a representative of Kumar & Associates, Inc. observed the excavation at the subject site on April 12, 2024 to evaluate the soils exposed for foundation support. The findings of our observations and recommendations for the foundation design are presented in this report. We previously conducted a subsoil study for design of foundations at the site and presented our findings in a report dated June 16, 2023, Project No. 23-7-274. The current observation was performed in accordance with our agreement for professional services with Maley Building Corporation dated April 5, 2024. The proposed residence will be a one- and two-story wood -frame structure. The proposed residence has been designed to be supported on spread footings sized for an allowable bearing pressure of 3,000 psf. At the time of our visit to the site, the foundation excavation had been cut in one level from 2 to 3 feet below the adjacent ground surface. The soils exposed in the bottom of the excavation consisted of a mix of sandy silty topsoil and silty sandy gravel and cobbles. No free water was encountered in the excavation and the soils were slightly moist to moist. It was recommended the topsoil encountered in the excavation be sub -excavated to expose the gravel subsoils. The sub -excavated depth can be backfilled with onsite granular soils moisture conditioned to near optimum moisture content and compacted to at least 98 percent of maximum standard Proctor density. The gravel soils exposed in the excavation and below the topsoil are consistent with those previously encountered on the site and suitable for support of spread footings designed for the recommended allowable bearing pressure of 3,000 psf. Topsoil and loose disturbed soils should be removed in the footing areas to expose the undisturbed natural granular soils. Other recommendations presented in our previous report which are applicable should also be observed. The recommendations submitted in this letter are based on our observation of the soils exposed within the foundation excavation and the previous subsurface exploration at the site. Variations in the subsurface conditions below the excavation could increase the risk of foundation Maley Building Corp. April 18, 2024 Page 2 movement. We should be advised of any variations encountered in the excavation conditions for possible changes to recommendations contained in this letter. Our services do not include determining the presence, prevention or possibility of mold or other biological contaminants (MOBC) developing in the future. If the client is concerned about MOBC, then a professional in this special field of practice should be consulted. If you have any questions or need further assistance, please call our office. Sincerely, Kumar & Associates, N. I -AA v; • 58663 James H. Parsons, U&q/,ZZ,� Rev. by: SLP JHP/kac cc: KA Designworks — Erik Hendrix — (erik ,ka-designworks.co_m) Kumar & Associates, Inc. 0 Project No. 23-7-274.A