HomeMy WebLinkAboutObservation of Excavation 08.24.2021K+AGeotechnical and Materials Engineers 5020 County Road 154
and Environmental Scientists Glenwood Springs, CO 81601
phone: (970) 945-7988
fax: (970) 945-8454
email: kaglenwood@kumarusa.com
An Employee Owned Company www.kumarusa.com
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
August 24, 2021
Aaron Natoniewski
4972 County Road 113
Carbondale, Colorado 81623
aaronnski (&hotmail. com
Project No. 20-7-414
Subject: Observation of Excavation, Proposed ADU, 4972 Cattle Creek Road, Garfield
County, Colorado
Dear Aaron:
As requested, the undersigned representative of Kumar & Associates, Inc. observed the
excavation at the subject site on August 23, 2021 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 provided preliminary recommendations for design of
foundations at the site and presented our findings in a report dated July 28, 2020, Project No.
20-7-414.
At the time of our visit to the site, the foundation excavation had been cut in two levels from
31/2 to 9 feet below the adjacent ground surface. The soils exposed in the bottom of the
excavation consisted mostly of stiff to hard, silty sandy clay with scattered gravel. Basalt
boulders were exposed on the north side of the deeper cut, uphill side of the excavation. No free
water was encountered in the excavation and the exposed soils were slightly moist to moist. The
subgrade had been compacted.
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 1,500 psf (or 2,000 psf for footings wider than 3 feet) as previously
recommended. Loose and disturbed soils should be removed in the footing areas to expose the
undisturbed natural 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 observations 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 do not include determining
the presence, prevention or possibility of mold or other biological contaminants (MOBC)
Aaron Natoniewski
August 24, 2021
Page 2
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, Inc.
o
Daniel E. Hardin, P.
24443 1
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Kumar & Associates, Inc. 0 Project No. 20-7-414