HomeMy WebLinkAboutObservation of Excavation 10.26.23
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
October 23, 2023 (Revised October 26, 2023)
Precision Built Construction Management
Attn: Brent Ritter
8106 County Road 117
Glenwood Springs, Colorado 81601
brent@precisionbuiltcm.com
Project No. 22-7-649
Subject: Observation of Excavation, Proposed Residence, Lot 32, Cerise Ranch,
664 Larkspur Drive, Garfield County, Colorado
Dear Brent:
As requested, the undersigned representative of Kumar & Associates, Inc. observed the
excavation at the subject site on October 20, 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 December 21, 2022, Project No. 22-7-649.
We amended our recommendations to include a spread footing alternative in a letter dated April
19, 2023.
The proposed residence will be a two-story wood frame structure over a basement. The
basement floor will be structural over a crawlspace and the garage floor will be slab-on-grade.
Foundations were designed for an allowable soil bearing pressure of 1,500 psf.
At the time of our visit to the site, the foundation excavation had been cut in 5 levels from 3 to
16 feet below the adjacent ground surface. The soils exposed in the bottom of the excavation
consisted of medium dense, silty sand and gravel to gravelly sandy silt. No free water was
encountered in the excavation and the soils were moist. The exposed subgrade appeared to have
been moistened and 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. Loose and disturbed soils should be removed in the footing areas
to expose the undisturbed natural soils. 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. 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