HomeMy WebLinkAboutObservation of Excavation 10.13.16H_P*KUMAR $tAl{JruEtJ 5020 County Road 154
Glenwood Springs, CO 81601
Phone: (970) S45"7988
Fax (970) 945'84s4
Email: hpkglenwood @ kumarusa.com
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Olfice Locations: Parker, Glenwood Springs, and Silverthorne, Colorado
+)October 13,20ï6
Pat & John V/eisbart
P.O. Box 3513
Boulder, Colorado 80307
i ohn.weisb¿rrt @r stuili l.conr
Project No. 16-7-523
Subject: Observation of Excavation, Proposed Residence, Lot ?8, Coryell Ranch, 143
Spirit Mountain Drive, Garfield County, Colorado
Dear Mr. & Mrs. Weisbart:
As rcque¡ited by Joe Striefcl, the undersigned rcpresentative of H-PlKumar observed the
excavation at the subject site on October 12,2016 to evaluate the soils exposed for foundation
sllpport. The findings of our observations and recommendations for the foundation design are
presented in this report. I{epworth-Pawlak Geotechnical (now H-P/Kumar) previously
conducted a subsoil study for design of foundations at the site and presented their findings in a
report dated June 30, 2016, Job No. 116275A'
The proposed residence will he a t\,vo story rvood frame stn¡cture over a crawlspace with an
attached garage. Thc garage tloor will be sl¿rtr-on-gracle. Foundations were ilesigned for an
allowable soil bearing pressure of 2,500 psf as recommended in the previotts subsoil study
f'ep0rt.
At the time of our visit to the site, the for¡ndation excavation had been cut in one level from 3 to
4 feet below the adjacent ground surfaçe. The soils expo.scd in the bottom of the excavation
consisted of elense, slightly silty sandy gravel with cobbles and small boulders. Several piles of
% inch road base had been placed on the crawlspace grade within the building arca. Footings
were bcing for¡ned at the time of our site visit. No free wûter was encountered in the excaval.ion
and the soils were slightly moist.
The natural gravel soils exposed in the excavatio¡l are consistent with those previously
encountered on the site and suitable for snpport of spread footings designed tbr the
recommended allowatrle bearing pressure of 2,500 psf. Loose and disturbed soils should be
removed in the footing ûre¿ls to expose the undisturbed natural soils. We understand that a few
i¡che.s of % inch road base will be compacted in low areas to re-establish design footing grade.
The roacl base slrould be ¡noistened and compacted to at least I007a of the maximum Standard
Proctor density. Other recommendations presented in our prcvious report which are applicable
should also be observed.
(OV -hok vþ?or
Pat & John Weisbart
October 13,20L6
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 incrcase the risk of
foundation movement. ri/e 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 concemed 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,
H-P+ l(U
Þ
Daniel E. Hardin, P.E.
Reviewed by:
DEH/ksw
cc: Joe Striefel
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H-F I KUMAR Project No. 16-7-523
