HomeMy WebLinkAboutObservation of Excavation
5020 County Road 154
Glenwood Springs, CO 81601
phone: (970) 945-7988
email: kaglenwood@kumarusa.com
www.kumarusa.com
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
August 14, 2025
Red House Architecture
Attn: Bruce Barth
815 Blake Avenue
Glenwood Springs, Colorado 81601
bruce@redhousearchitecture.com
Project No. 25-7-523
Subject: Observation of Excavation, Proposed Residence, Lot IS-18, Aspen Glen,
279 Wildflower Lane, Garfield County, Colorado
Gentlemen:
As requested, a representative of Kumar & Associates, Inc. observed the excavation at the
subject site on August 12, 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. Hepworth-Pawlak Geotechnical (now Kumar & Associates) previously conducted a
subsoil study for design of foundations at the site and presented the findings in a report dated
August 12, 2015, Job No. 115 343A. the current observation was performed in accordance with
our agreement for professional services with Red House Architecture dated August 8, 2025.
The proposed residence has been designed to be supported on spread footings placed on the
natural soils and sized for the recommended allowable bearing pressure of 1,200 psf.
At the time of our visit to the site, the foundation excavation had been cut in one level from
about 2 to 4 feet below the adjacent ground surface. The soils exposed in the bottom of the
excavation consisted of stiff, sandy silty clay. Results of swell-consolidation testing performed
on a sample taken from the site, shown on Figure 1, indicate the soils have low to moderate
compressibility under conditions of loading and wetting. The laboratory test results are
summarized in Table 1. No free water was encountered in the excavation and the soils were
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 1,200 psf. Loose disturbed soils in the footing areas should be moistened
and compacted. Other recommendations presented in the 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 in
this special field of practice should be consulted.
Kumar & Associates
TABLE 1
SUMMARY OF LABORATORY TEST RESULTS
Project No. 25-7-523
SAMPLE
LOCATION NATURAL
MOISTURE
CONTENT
NATURAL
DRY
DENSITY
GRADATION PERCENT
PASSING
NO. 200
SIEVE
ATTERBERG LIMITS UNCONFINED
COMPRESSIVE
STRENGTH SOIL OR
BEDROCK TYPE BOTTOM OF
EXCAVATION
GRAVEL SAND LIQUID
LIMIT
PLASTIC
INDEX (%) (%)
(%) (pcf) (%) (%) (PSF)
South Side 9.5 112 71 Sandy Silty Clay
North Side 12.5 110 Sandy Silty Clay