HomeMy WebLinkAboutObservation of Excavation 08.03.2021
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 3, 2021
Maley Building Corporation
Attn: Patrick Maley
P.O. Box 4028
Basalt, Colorado 81621
patrick@maleybuilding.com
Project No. 21-7-625
Subject: Observation of Excavation, Proposed Residence, 33 St. Finnbar Road, Lot 5,
St. Finnbar Farms, Garfield County, Colorado
Dear Patrick:
As requested, a representative of Kumar & Associates observed the excavation at the subject site
on July 26, 2021 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 Maley Building Corporation dated July 26, 2021.
The residence will be one story wood frame construction over a crawlspace with an attached
garage. Foundations were designed for an assumed allowable soil bearing pressure of 3,000 psf
based on the original preliminary soils report for the subdivision by H-P Geotech, dated
August 4, 1998, Job No. 198-483.
At the time of our visit to the site, the foundation excavation had been cut in one level from
2½ to 3 feet below the adjacent ground surface. The soils exposed in the bottom of the
excavation consisted of slightly silty sandy gravel with cobbles and small boulders. The results
of a gradation analysis performed on a sample of the gravel soils (minus 3-inch fraction)
obtained from the site are presented on Figure 1. No free water was encountered in the
excavation and the soils were slightly moist to moist.
Considering the conditions exposed in the excavation and the nature of the proposed
construction, spread footings placed on the undisturbed natural soil designed for an allowable
soil bearing pressure of 3,000 psf can be used for support of the proposed residence. 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
10 feet. Foundation walls acting as retaining structures should also be designed to resist a lateral
earth pressure based on an equivalent fluid unit weight of at least 45 pcf for on-site soil as
backfill. The crawlspace grade should be placed as high as practical due to the shallow