HomeMy WebLinkAboutObservation of Excavation 05.27.2025
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
May 27, 2025
Richard Nash
965 Westbank Road
Glenwood Springs, Colorado 81601
richard@nashconstructioncompany.com
Project No. 25-7-342
Subject: Observation of Excavation, Proposed Garage Addition, 965 Westbank Road,
Garfield County, Colorado
Dear Richard:
As requested, a representative of Kumar & Associates observed the excavation at the subject
site on May 16, 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 general accordance with our agreement for professional engineering
services to you dated May 16 , 20 25 .
The proposed garage addition will be a single-story wood-frame accessory dwelling unit (ADU)
built on the west side of the existing garage. The addition has been designed to be supported on
spread footings sized for an assumed allowable bearing pressure of 1,500 psf.
At the time of our visit to the site, the foundation excavation had been cut in 1 level from about
3½ to 4 feet below the adjacent ground surface. The soils exposed in the bottom of the excavation
consisted of medium dense, silty sandy gravel with scattered cobbles. The results of a gradation
analysis performed on a sample of silty sandy gravel (minus 3-inch fraction) obtained from the
site are presented on Figure 1. No free water was encountered in the excavation and the soils
were slightly moist to 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 1,500 psf should be adequate for support of the proposed addition. The
exposed matrix soils may tend to compress when wetted and result in some post-construction
settlement of the foundation if the bearing soils become wet. Footings should be a minimum width
of 16 inches for continuous walls and 2 feet for columns. Loose disturbed soils in footing areas