HomeMy WebLinkAboutObservation of ExcavationlGn Hffifl*Tffifniivi**
5020 County Road 154
Glenwood Springs, CO 81601
phone: (970) 945-7988
email: kaglenwood@kumarusa,com
www.kumarusa.com
An Employcc Owncd Compony
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
June 26,2025
Level Build Co
Attn: Scott Baltzer
136 Sunlight Drive
Glenwood Springs, Colorado 81601
scott. levelbuildco@omail. com
Project No. 25-7-436
Subject:Observation of Excavation, Proposed Detached Garage, 138 Sunlight Drive,
Garfield County, Colorado
Scott:
As requested, a representative of Kumar & Associates observed the excavation at the subject
site on June 23, 2025 to evaluate the soils exposed for foundation support, The findings of our
observations and recommendations for the foundation support are presented in this report. The
services were performed in accordance with our agreement for professional engineering
services to Level Build Co dated June 23, 2025.
The proposed garage has been designed to be supported on spread footings sized for an
assumed allowable bearing pressure of 1,500 psf.
At the time of our visit to the site, the foundation excavation had been cut in one level from
about 1 to7 feet below the adjacent ground surface. The soils exposed in the bottom of the
excavation consisted of stiff, sandy clay. Results of swell-consolidation testing pefformed on a
clay sample taken from the site, shown on Figure 1, indicate the soils are slightly to moderately
compressible under conditions of loading and wetting. No free water was encountered in the
excavation and the soils were moist.
Considering the conditions exposed in the excavation and the nature of the proposed
construction, spread footings placed on the undisturbed natural clay soil designed for an
allowable bearing pressure of 1,500 psf should be adequate for support of the proposed garage
The exposed soils tend to compress when wetted and there could be some post-construction
settlement of the foundation mainly if the bearing soils become wet. Footings should be a
minimum width of 16 inches for continuous walls and 2 feet for columns. Loose and disturbed
soils in footing areas should be removed and the bearing level extended down to the
undisturbed natural soils. Exterior footings should be provided with adequate soil cover above
their bearing elevations for frost protection. Continuous foundation walls should be reinforced
top and bottom to span local anomalies such as by assuming an unsupported length of at least
12 feet. Foundation wallg acting as retaining structures (if any) should also be designed to
resist a lateral earth pressure based on an equivalent fluid unit weight of at least 50 pcf for
imported granular soil as backfill. A perimeter foundation drain should be provided to prevent
temporary buildup of hydrostatic pressure behind retaining walls (if any). Structural fill placed
within floor slab areas can consist of the on-site soils or imported granular soil such as CDOT
Class 6 base course compacted to at least 95% of standard Proctor density at a moisture
content near optimum. Backfill placed around the structure should be compacted and the
LevelBuild Co
June26,2O25
Project No.25-7-436
Page2
surface graded to prevent ponding within at least 10 feet of the building. Landscape that
requires regular heavy irrigation, such as sod, and sprinkler heads should not be located within
5 feet of the foundation.
The recommendations submitted in this letter are based on our observation of the soils exposed
within the foundation excavation and do not include subsurface exploration to evaluate the
subsurface conditions within the loaded depth of foundation influence. This study is based on
the assumption that soils beneath the footings have equal or better support than those exposed.
The risk of foundation movement may be greater than indicated in this report because of
possible variations in the subsurface conditions. ln order to reveal the nature and extent of
variations in the subsurface conditions below the excavation, drilling would be required. lt is
possible the data obtained by subsurface exploration could change the 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. lf the
client is concerned about MOBC, then a professional in this special field of practice should be
consulted.
lf you have any questions or need further assistance, please call our office.
Sincerely,
Kumar & Associates, I
Steven L. Pawlak, P
SLP/kac
Attachment Figure 1 -Test Results
Kumar & Associates, lnc.@
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