HomeMy WebLinkAboutExcavation Observation Report1f+AAssoollata, Inc. -Kumar &
Geotechnical and Materials Engineers 5020 County Road 154
and Environmental Scientists Glenwood Springs, CO 81601
phone: (970) 945-7988
fax: (970) 945-8454
email: kaglenwood@kumarusa.com
An Employee Owned Company www.kumarusa.com
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
August 16, 2021
Trish Cerise
16724 Highway 82
Carbondale, Colorado 81623
trishceriseggmail.com
Project No. 21-7-138.3
Subject: Observation of Excavation, Proposed Residence, Lot 3, Cerise Minor
Subdivision, 16714 Highway 82, Garfield County, Colorado
Dear Trish:
As requested, the undersigned representative of Kumar & Associates, Inc. observed the
excavation at the subject site on August 13, 2021 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 February 15, 2021, Project No. 21-7-138.3.
The proposed residence will be a single story, wood frame structure over a full basement level
with an attached garage. Foundations were designed for an allowable soil bearing pressure of
2,000 psf.
At the time of our visit to the site, the foundation excavation had been cut in three levels about
6%2 to 9 feet below the adjacent ground surface. The soils exposed in the bottom of the
excavation consisted of silty sandy gravel with cobbles. Free water was observed in the bottom
of the excavation in the northeast portions of the excavation. A sump pit had been excavated in
the southeast corner of the basement excavation and the volume of water being pumped was
estimated at 3 to 5 gallons per minute. The house and garage excavations appeared to be
complete and the footing forms were being laid out by the concrete subcontractor.
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 2,000 psf. Loose and disturbed soils should be
removed in the footing areas to expose the undisturbed natural soils. Due to the presence of
groundwater in the bottom of the excavation, we recommend that, in addition to the perimeter
drain previously recommended, that a layer of screened rock be placed below the proposed
basement slab and be connected by a pipe preferably sloped to daylight or to a permanent sump
and pump pit located in the area of the existing sump. 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 limited subsurface exploration at the site.
Trish Cerise
August 16, 2021
Page 2
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.
i
vt
Daniel E. Hardin, P. ;
Rev. by: SLP
DEH/kac
cc: Terry Dudycha (tkd
Kumar & Associates, Inc. 0 Project No. 21-7-138.3