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HomeMy WebLinkAboutObservation of Excavation 08.07.2025 5020 County Road 154 Glenwood Springs, CO 81601 phone: (970) 945-7988 email: kaglenwood@kumarusa.com www.kumarusa.com Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado August 7, 2025 Janckila Construction Attn: Alex Janckila 75 Buckskin Drive Carbondale, Colorado 81623 alex@janckilaconstruction.com Project No. 25-7-485 Subject: Observation of Excavation, Proposed Addition, Lot 3, Roaring Fork Mesa at Aspen Glen, 226 Brookie, Garfield County, Colorado Dear Alex: As requested, a representative of Kumar & Associates observed the excavation at the subject site on July 30, 2025 to evaluate the soils exposed for foundation support. The findings of our observations and recommendations for the foundation support are presented in this report. The services were performed in accordance with our agreement for professional engineering services to Janckila Construction dated July 25, 2025. We understand the proposed addition has been designed to be founded on spread footings placed on the natural soils and sized for an allowable bearing pressure of 2,000 psf. At the time of our visit to the site, the foundation excavation had been cut in one level from 3½ to 4 feet below the adjacent ground surface. The soils exposed in the bottom of the excavation consisted of sandy clay. Foundation wall backfill was exposed in the bottom of the southeast corner of the excavation along the foundation wall of the existing residence. The bottom of the footing of the existing residence was exposed in the southwest side of the excavation. Results of moisture content, dry density, and percent finer than sand size (-#200) gradation testing performed on a sample of the natural sandy clay taken from the site are 11.8 percent moisture, 115 pcf, and 71 percent, respectively. No free water was encountered in the excavation, and the soils were moist. Considering the conditions exposed in the excavation and the nature of the proposed construction, spread footings placed on the undisturbed natural soil designed for an allowable soil bearing pressure of 2,000 psf can be used for support of the proposed addition. The new footing should be doweled into the foundation wall of the existing residence in order to span the foundation wall backfill exposed in the southeast corner of the excavation. The exposed soils tend to compress when wetted and there could be some post-construction settlement of the foundation if the bearing soils become wet. The settlement could be differential to the existing residence foundation. Footings should be a minimum width of 16 inches for continuous walls and 2 feet for columns. Loose and disturbed soils in footing areas should be removed and the bearing level extended down to the undisturbed natural soils or the new footing doweled into the