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5020 County Road 154
Glenwood Springs, CO 81601
phone: (970) 945-7988
fax: (970) 945-8454
email: kaglenwood@kumarusa.com
www.kumarusa.com Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
November 8, 2023
Esau Ruiz
6799 County Road 346
Silt, Colorado81652
esauruiz90@gmail.com
Project No. 22-7-349.01
Subject: Observation of Excavation, Proposed Accessory Dwelling Unit Residence, Lot 1,
Ruiz South Minor Subdivision, County Road 331 & 346, Garfield County,
Colorado
Dear Esau:
As requested, a representative of Kumar & Associates observed the excavation at the subject site
on November 3, 2023 to evaluate the soils exposed for foundation support. The findings of our
observations and recommendations 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
February 24, 2023, Project No. 22-7-349.01.
The accessory dwelling unit (ADU) will be a single-story structure. The ground floor will be
slab-on-grade. The residence will be supported on spread footings sized for an allowable bearing
pressure of 1,200 psf, as recommended with some risk of settlement.
At the time of our visit to the site, the foundation excavation had been cut in one level from ½ to
2½ feet below the adjacent ground surface. The soils exposed in the bottom of the excavation
consisted of stiff, sandy clay and silt. Results of swell-consolidation testing performed on
samples taken from the site, shown on Figure 1, indicate the soils are moderately compressible
under conditions of loading and wetting with a low hydro-compression potential. 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 1,200 psf. The risk of settlement is primarily if the bearing soils were to
become wetted and precautions should be taken to prevent wetting. Loose disturbed soils should
be removed in the footing areas to expose the undisturbed natural soils, and the subgrade
moistened and compacted. 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 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.
Kumar & Associates