HomeMy WebLinkAboutObservation of Excavation 02.21.20221(+A ni Asat�s, inc. 11
Geotec s¢cl
Geotechnicai 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
February 21, 2022
Stangl & Son Builders
Attn: Geoff Stangl
P.O. Box 3680
Basalt, Colorado 81621
aeoffna ,,stanp-lbuilders. com
Project No. 21-7-933
Subject: Observation of Excavation, Proposed Residence, Lot 12, Saint Finnbar Farm,
Saint Finnbar Farm Road, Garfield County, Colorado
Gentlemen:
As requested, a representative of Kumar & Associates, Inc. observed the excavation at the
subject site on February 17 and 18, 2022 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 January 17, 2022, Project No. 21-7-933.
The proposed residence location and design are essentially the same as described in our previous
report. The residence will be above crawlspace in the living area with a slab -on -grade floor in
the garage.
At the time of our initial visit to the site, the building excavation had been rough cut in one level
from 21h to 4 feet below the adjacent ground surface. The soils exposed in the bottom of the
excavation were variable and consisted of silty sandy gravel with cobbles in the western part and
interlayered sand, silt and clay up to about 2 feet deep in the eastern part including all of the
garage area. When observed on February 18 late afternoon, the softer soils had been mostly
removed to about an additional 2 feet deep to expose the relatively dense, silty sandy gravel with
cobbles. A vein of sand/silt with roots about 1-foot thick extended west into the north -central
part of the residence area and additional excavation was recommended to remove the softer
layer. The garage area was beginning to be backfilled with onsite granular material. No free
water was encountered in the excavation and the soils were moist to very moist.
The natural granular soils exposed in the excavation and compacted structural backfill are
consistent with the conditions expected at the site and suitable for support of spread footings
designed for the recommended allowable bearing pressure of 2,500 psf. Loose disturbed soils
should be removed to expose the undisturbed natural gravel soils prior to placing structural fill or
foundation concrete. The bearing soils should be protected from frost and concrete should not be
placed on frozen soils. Other recommendations presented in our previous report which are
applicable should also be observed.
Stangl & Son Builders
February 21, 2022
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.
F�/
Steven L. Pawh
SLP/kac
Kumar & Associates, Inc. ` Project No. 21-7-933