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HomeMy WebLinkAboutObservation of Excavation 12.01.25Kumar & Associates, Inc.® 5020 County Road 154 K +A Geotechnical and Materials Engineers Glenwood Springs, CO 81601 and Environmental Scientists phone: (970) 945-7988 email: kaglenwood@kumarusa.com www.kumarusa.com An Employee la1M ed Compony Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado December 1, 2025 Western Slope Builders Attn: Taylor Parsons 6873 Highway 82 Glenwood Springs, Colorado 81601 taylor(cDwesternslopebuilders.com Project No. 21-7-608.A Subject: Observation of Excavation, Proposed Residence, Lot 31, Filing 5, Los Amigos Ranch, 587 Elk Springs Drive, Garfield County, Colorado Gentlemen: As requested, a representative of Kumar & Associates, Inc. observed the excavation at the subject site on November 28, 2025 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 August 31, 2021, Project No. 21-7-608. The current observation was performed in accordance with our agreement for professional services with Western Slope Builders dated November 4, 2025. The proposed residence has been designed to be supported on spread footings sized for the recommended allowable bearing pressure of 2,500 psf. At the time of our visit to the site, the excavation for the residence had been cut in 2 levels from about 4 to 12 feet below the adjacent ground surface with a step of about 2 feet between levels near the downhill south side. The soils exposed in the bottom of the excavation consisted of basalt cobbles and boulders in a calcareous sand silt matrix. CDOT Class 6 road base of around 1 to 2 feet deep had been placed and compacted to develop the design bearing levels. The garage area had been rough cut into the basalt rock soils. No free water was encountered in the excavation and the soils were slightly moist. The soil conditions exposed in the excavation are consistent with those previously encountered on the site and suitable for support of spread footings designed for the recommended allowable bearing pressure of 2,500 psf. Loose disturbed soils (such as in the garage area) should be removed as much as practical and base course placed and compacted to at least 95% of standard Proctor density at near optimum moisture content. The bearing soils should be protected from frost and concrete should not be placed on frozen 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 limited subsurface exploration at the site. Variations in the subsurface conditions below the excavation could increase the risk of foundation movement. We should be advised of any variations encountered in the excavation conditions for possible changes to recommendations contained in this letter. Our services Western Slope Builders December 1, 2025 Project No. 21-7-608.A Page 2 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, Steven L. Pawlak, SLP/kac i 15229 � ..'G t�ss1(}NAl •EN�� Kumar & Associates, Inc