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Hepworth- Parclak Geotechnical, Inc.
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50- G,untp Road 154
Glen"-,-A Springs, Colorado 31601
Phone: 970 -945- 1953
HEPWORTH - PAWLAK GEOTECHNICAL
Fax: 970.9}5 - 845}
email: hpeeo�hp�eutech.rnn
August 11, 2011
Dave Hilb
1465 Aspen Grove Lane
Vail, Colorado 81657
dhilb @comcast.net
AUG 112011
TOWN OF VAIL
Q \1 -o\
Job No. 111 086A
Subject: Observation of Excavation, Proposed Residence, Lot 5, Vail
Intermountain, 2644 Larkspur Lane, Vail, Colorado
Dear Dave:
As requested, a representative of Hepworth - Pawlak Geotechnical, Inc. observed the
excavation at the subject site on August 1, 3 and 11, 2011 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 May 12,
2011, Job No. 111 086A.
The proposed residence is essentially the same as described in our previous report.
Spread footings sized for the recommended allowable bearing pressure of 2,500 psf were
assumed for the building support. Extensive excavation depth will be needed due to the
relatively steep, north facing hillside terrain above Larkspur Drive.
At the time of our first two visits to the site, the building excavation was progressing from
the uphill, south part down to the north and had been cut in multiple levels from roughly
10 to 28 feet below the adjacent ground surface. The steps in grade between levels were
typically 2 to 3 feet but also up to 12 feet in places. When observed on August 11, the
excavation was complete including the northeast part consisting of the garage area with a
cut depth of 4 feet at the downhill front side. The soils exposed in the bottom of the
excavation consisted of medium dense clayey silty sand with gravel and scattered
cobbles. No free water was encountered in the excavation and the soils were moist.
The 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 2,500 psf. Any loose disturbed soils should
be removed in the footing areas to expose the undisturbed natural soils. Other
recommendations presented in our previous report which are applicable, especially those
to provide subdrains to protect the lower levels from wetting, 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
Parker 303 - 841 - 7110 • Colorado Springs 719 -633 -5562 • Silverthurn,, 970- 468 -1989
Dave Hilb
August 11, 2011
Page 2
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,
HEPWORTH — PAWLAK GEOTECHNICAL, INC.
N�__
Steven L. Pawlak, P.E. * 1 5 2 2 2
Rev. by: DAY
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Jul) IVO. 1 11 U60A