HomeMy WebLinkAboutExcavation Observation 12.05.20221f+A Geotechnical 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
December 5, 2022
Zag Built
Attn: Mike Zagrzebski
2379 W. Ridges Road
Grand Junction, Colorado 81507
zagbuiltazagbuilt.net
Project No. 21-7-904.A
Subject: Observation of Excavation, Proposed Residence, Lot SD-15, Aspen Glen,
Sundance Trail, Garfield County, Colorado
Dear Mr. Zagrzebski:
As requested, the undersigned representative of Kumar & Associates, Inc. observed the
excavation at the subject site on December 5, 2022 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 January 26, 2022, Project No. 21-7-904.
The proposed residence will be a two-story wood frame structure over a crawlspace. The
attached garage will have a slab -on -grade floor. Foundations were designed for an allowable soil
bearing pressure of 3,000 psf based on our previous report.
At the time of our visit to the site, the foundation excavation had been cut in one level from 2
to 4 feet below the adjacent ground surface. The soils exposed in the bottom of the excavation
mainly consisted of relatively dense, slightly silty sandy gravel with cobbles. No free water was
encountered in the excavation and the soils were moist. We understand that some clay was
encountered at footing grade overlying the natural gravel soils. The clay soils were sub -
excavated down to the underlying gravel soils and footing grade was re-established with the
compacted on -site gravel soils as fill.
The natural gravel soils 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 3,000 psf. Loose and disturbed gravel soils should
be compacted in footing areas. The bearing soils should be protected from frost and concrete
should not be placed on frozen soils. There could be some settlement of the gravel fill areas
relative to the natural gravel areas. 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
Zag Built
December 5, 2022
Page 2
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) 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.
Dan
Rev
DEH/kac
Kumar & Associates, Inc. � Project No. 21-7-904.A