HomeMy WebLinkAboutObservation of Excavation 06.25.24Kumar & Associates, Inc.
'( Geotechnical and Materials Engineers 5020 County Road 154
and Environmental Scientists Glenwood Springs, CO 81601
phone. (970) 945-7988
fax: (970) 945-8454
email: kaglenwoodCkumarusa.com
An Employee owned Company www.kumarusa.com
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
June 25, 2024
Bella Villa Builders
Attn: Russell Burton
P.O. Box 875
Conifer, Colorado 80433
russellburtonkb ellavillabuilders. com
Project No. 24-7-369
Subject: Observation of Excavation, Proposed Residence, Lot H35, Aspen Glen,
174 Saddleback Road, Carbondale, Colorado
Dear Russell:
As requested, a representative of Kumar & Associates, Inc. observed the excavation at the
subject site on June 25, 2024 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 observed the subgrade a week ago and recommended that the fine-grained clay
soils be removed from below proposed footings in the crawlspace area on the north, garage side
of the excavation. A subsoil study for design of foundations at the site was previously performed
by Hepworth-Pawlak Geotechnical and presented in a report dated November 28, 2014, Job No.
114 506A. Footings designed for an allowable soil bearing pressure of 2,500 psf were
recommended in the previous report for support of the residence.
At the time of our June 17, 2024 visit to the site, the foundation excavation had been mostly
excavated with the basement area bearing on relatively dense gravel soils. The northern
crawlspace and garage area transitioned to the upper clay soils. We recommended that the
footings be lowered to bear on the dense gravel soils to avoid potential differential settlement
between portions of the house that are on the dense gravel soils and portions on the upper clay
soils.
We revisited the site on June 25, 2024 and observed that the clay soils had been removed and the
exposed subgrade consisted of the dense sandy gravel soil cut in one main level from 8 to 10 feet
below the adjacent ground surface. The soils exposed in the bottom of the excavation consisted
of slightly silty sand and gravel with cobbles. No free water was encountered in the excavation
and the soils were slightly moist to moist.
The gravel 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 the previous report which are applicable should also be observed.
Bella Villa Builders
June 25, 2024
Page 2
The recommendations submitted in this letter are based on our observation of the soils exposed
within the foundation excavation and the previous limited 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.
If you have any questions or need further assistance, please call our office.
Sincerely,
Kumar & Associates, Inc.
Daniel
Rev. b
DEH/]
Kumar & Associates, Inc. 0 Project No. 24-7-369