HomeMy WebLinkAboutObservation of Excavation 08.18.2023
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
August 18, 2023
DZ Remodeling
Attn: Carrie Dion
113 9th Street, #907
Glenwood Springs, Colorado 81601
carrie@dzremodeling.com
Project No. 23-7-484
Subject: Observation of Excavation, Proposed Johnson Residence Addition, 0471 County
Road 112, Garfield County, Colorado
Carrie:
As requested, a representative of Kumar & Associates, Inc. observed the excavation at the
subject site on August 15, 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. The observation was performed in accordance with our agreement for professional
services with DZ Remodeling dated August 14, 2023.
The addition will connect the residence to the detached garage and be a single-story structure
above crawlspace. Spread footings placed on the natural soils were designed for the foundation
support.
At the time of our visit to the site, the foundation excavation had been cut in 2 levels from about
1½ to 3½ feet below the adjacent ground surface. Existing footings for the existing residence
and garage were exposed in some areas. The soils exposed in the bottom of the excavation
mainly consisted of stiff, sandy silty clay. Screened rock had been placed over the natural clay
soils in the deeper cut, eastern part of the excavation. Results of swell-consolidation testing
performed on a clay sample taken from the site, shown on Figure 1, indicate the soils are low to
moderately compressible under conditions of loading and wetting with a minor expansion
potential when wetted under light load. No free water was encountered in the excavation and the
soils were slightly moist to moist.
The soil conditions exposed in the excavation are generally consistent with those which can be
encountered in the area of the site and can be used for support of spread footings designed for an
allowable bearing pressure of 1,500 psf with a risk of differential movement mainly if the
bearing soils are wetted. Because of the movement risk, precautions should be taken to prevent
wetting of the bearing soils including removal of the screened rock in footing areas to expose the
native soils. Other loose disturbed soils should be removed in the footing areas to expose the
undisturbed natural soils. Foundation wall backfill should be well compacted and have a
positive slope away from the foundation for a distance of at least 5 feet.
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 at the site.
Kumar & Associates