HomeMy WebLinkAboutObservation of ExcavationK+AKumar & Associates, Inc.® 5020 County Road 154
Geotechnical and Materials Engineers Glenwood Springs, CO 81601
and Environmental Scientists phone: (970) 945-7988
email: kaglenwood@kumarusa.com
—�� www.kumarusa.com
An Employ" Owned Company
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
July 10, 2025
Boulder Construction Services, LLC
Attn: Matt Jurmu
901 CR 231
Silt, Colorado 81652
Matt.iurmu(aD-boulderes.com
Project No. 21-7-768.A
Subject: Observation of Excavation, Proposed Residence, Lot 42, Filing 9, Elk Springs,
3030 Elk Springs Drive, Garfield County, Colorado
Dear Matt:
As requested, a representative of Kumar & Associates, Inc. observed the excavation at the
subject site on July 3 and 10, 2025 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 October 27, 2021, Project No. 21-7-768.
We understand the proposed residence has been designed to be founded on spread footings
placed on the natural granular soil or basalt rock and sized for an allowable bearing pressure of
2,500 psf.
At the time of our visit to the site on July 3, 2025, the foundation excavation had been cut in one
level from 3 to 8 feet below the adjacent ground surface. The soils exposed in the bottom of the
excavation consisted of basalt cobbles and boulders in a sandy silt matrix and basalt flow.
Blasting was required to excavate the basalt flow. We recommended that a thin layer of
compacted 3/-inch aggregate base course be placed in the bottom of the excavation as a leveling
course. At the time of our visit to the site on July 10, 2025, up to 6-inches of 3/-inch aggregate
base course had been placed in the bottom of the excavation as a leveling course. The base
course appeared to have been adequately compacted with a walk -behind sheep's foot compactor.
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 2,500 psf. 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 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. Our services do not include
Boulder Construction Services, LLC
July 10, 2025
Project No. 21-7-768.A
Page 2
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.
Robert L. Duran, P.E. _
Reviewed by:
24443
Daniel E. Hardin, P
RLD/kac
Kumar & Associates, Inc