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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 20, 2023
Jose Chavez
50323 County Road 336, Trailer 33
New Castle, Colorado 81647
mountainpeakinsulation@yahoo.com
Project No. 23-7-388
Subject: Observation of Excavation, Proposed Residence, 1113 County Road 331,
Garfield County, Colorado
Dear Jose,
As requested, a representative of Kumar & Associates, Inc. observed the excavation at the
subject site on November 15, 2023 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 9, 2023, Project No. 23-7-388.
In our previous report, we recommended that the proposed residence be founded on spread
footings bearing on the natural granular soils beneath any fine-grained soils and sized for an
allowable soil bearing pressure of 2,500 psf. We understand that the foundation was designed as
spread footings bearing on the natural fine-grained 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 ½ to
5 feet below the adjacent ground surface and the footings had already been poured. The soils
exposed in the bottom of the excavation consisted of sandy silty clay. 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 and exhibit a low
hydrocompression potential when wetted under a constant 1,000 psf surcharge. No free water
was encountered in the excavation and the soils were slightly moist to moist.
The soil conditions exposed in the excavation are consistent with those previously encountered
on the site. Spread footings placed on the fine-grained soils exposed in the excavation will have
a risk of differential settlement due to the variable low bearing capacity and low
hydrocompression potential of the sandy silty clay soils, especially if the bearing soils become
wetted. The clay soils exposed in the excavation are suitable for support of spread footings
designed an allowable bearing pressure of 2,000 psf with a risk of post construction settlement,
especially if the bearing soils become wetted. A lower risk of settlement would be to place the
footings entirely on the natural granular soils that underlie the upper fine-grained 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
Kumar & Associates
Kumar & Associates